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mark vaughn View Drop Down
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    Posted: 06 Feb 2012 at 9:15pm
I saw where you asked a question about the affects of a larger diameter lifter compared to the smaller lifter.  My answer would be pretty much the same as Brian Jasper CO. La gave.  There is only one racing class engine that i build anymore that has a flat tappet cam and that is a 305 cid sprint car class, and only because that is the rules, a solid lift flap tappet and chevy stock diameter lifter.  I havent tried a bigger lifter on a camshaft since the 70's . I have two ex NASCAR Dodge engines in the shop right now and they have flat tappet cams in them because thats the rules.  One has a camshaft in it that are 60 mm cam journals , it has 1.375 base circles lobes, .380 lobe lifts and 2.25 rocker ratios =.855 valve lift.  The other I had crane cams build a roller cam for it and put that engine in a dirt late model.  Now for my answer about larger diameter lifters on the same camshaft specs.  Ive not seen much gains in actual performance myself.  But what do i know, im just an ole arkansas boy that grew up on Allis Chalmers!! 
 
P.S.  anybody elses input on the subject would be appriciated.
Thanks,
Mark
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Post Options Post Options   Thanks (0) Thanks(0)   Quote D-17_Dave Quote  Post ReplyReply Direct Link To This Post Posted: 06 Feb 2012 at 9:47pm
Nascar left the hydraulic lifter because the rpm's against the lift durations would work the oil pressure out of the lifters and allow the valves to not open. At least that's one of the reasons.
I have no real comment on the diam. issue with the lifters other than to say that a lifter contacts the cam based on the flat edge or width of the lobe and lifter as the rotation angle of the lobe is constantly changing. The force applied is applied from the valve spring. Closing rates based on moving the mass of the lifter and the valve require a certain rated spring tension. So, I would guess that a certain diam. lifter is required to supply enough surface area between the lifter and cam lobe to maintain an oil film so friction doesn't regrind the cam while running. Since a key component of oil has been removed in the last few years you see most engine manufacturers have switched to roller cams. But, I believe that ANY lifter needs to be large enough to support the oil film. Other than this I see where it is of no issue.
Yea, I can fix that.....
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian Jasper co. Ia Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 12:05pm

If I remember correctly, part of the discussion I was reading talked about the lifter diameter and too small of a lifter would have the edge of the lifter dig into the lobe. I still need to give Barry Rabotnik a call so I can decide which cam to use in the 445 FE...

"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 427435 Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 3:13pm
Originally posted by Brian Jasper co. Ia Brian Jasper co. Ia wrote:

If I remember correctly, part of the discussion I was reading talked about the lifter diameter and too small of a lifter would have the edge of the lifter dig into the lobe. I still need to give Barry Rabotnik a call so I can decide which cam to use in the 445 FE...



That is the real problem with a high lift cam and a small diameter lifter.
Mark

B10 Allis, 917 Allis, 7116 Simplicity, 7790 Simplicity Diesel,
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Ignorance is curable-----stupidity is not.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Butch(OH) Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 4:20pm
Since those with sense are going to talk about it I will add my two cents.
If I remember the question correctly he asked what was to gain from increasing the diameter of the lifter and the answer is nothing given that the cam is at optimum and the condition Brian mentioned is met. If a cam profile is not at optimum and cannot be ground as desired due to the ramp being at the edge of the lifter then yes, gains could be had by increasing the diameter of the lifter. The cam grinder can reduce the base circle to accomplish the same thing. All in all it's one of those things that just plain isnt worth a whole lot of chat unless a person cant get a grip upon what is going on with the cam and lifter to begin with.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rod B Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 4:42pm
He was makeing a lot of comments about spinning a 226 engine and he's been fishing for wi50 like alwayse after seeing the pictures.  It's pankey being himself.
 
Next he will post about everyone being caught up in all things shiney like last time.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mlpankey Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 4:55pm
The larger the diameter lifter will have a cam with a larger flank. Just a tn boy who uses a.mississippi harold brookshire cams Ams
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gary in da UP Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 5:01pm
Please explain flank, in cam grinder terminology for me please, I have never heard that term used before. And thanks in advance panky.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mlpankey Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 5:35pm
Flank is defined as the end of the ramp section to the point the lifter reaches maximum velocity
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mlpankey Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 7:22pm
Originally posted by Butch(OH) Butch(OH) wrote:

Since those with sense are going to talk about it I will add my two cents.
If I remember the question correctly he asked what was to gain from increasing the diameter of the lifter and the answer is nothing given that the cam is at optimum and the condition Brian mentioned is met. If a cam profile is not at optimum and cannot be ground as desired due to the ramp being at the edge of the lifter then yes, gains could be had by increasing the diameter of the lifter. The cam grinder can reduce the base circle to accomplish the same thing. All in all it's one of those things that just plain isnt worth a whole lot of chat unless a person cant get a grip upon what is going on with the cam and lifter to begin with.
  a .842 diameter solid lifter on a 230 duration @ .050 will lift a valve with a 1.5 rocker to .480 lift . use the amc .904 lifter same length as the gm just bigger in diameter with same cam and rocker net valve lift is .515   its worth getting a grip on . The lifter diameter is also taken into account whe a cam designer is figuring the intesity of the flank for another term pressure angle. Anology we back into a parking spot with a 14 inch tired toyota corolla when we roll up against it we drop the clutch car lunges hard up against it and dies due to the small diameter tires pressure angle. Now we back our 16.9/38 tired 40 hp tractor up against it at a idle drop clutch and where over the curb and in the space behind the curb due to the larger tire diameter having a less pressure angle .

Edited by mlpankey - 07 Feb 2012 at 8:01pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Butch(OH) Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 7:58pm
Originally posted by mlpankey mlpankey wrote:

Originally posted by Butch(OH) Butch(OH) wrote:

Since those with sense are going to talk about it I will add my two cents.
If I remember the question correctly he asked what was to gain from increasing the diameter of the lifter and the answer is nothing given that the cam is at optimum and the condition Brian mentioned is met. If a cam profile is not at optimum and cannot be ground as desired due to the ramp being at the edge of the lifter then yes, gains could be had by increasing the diameter of the lifter. The cam grinder can reduce the base circle to accomplish the same thing. All in all it's one of those things that just plain isnt worth a whole lot of chat unless a person cant get a grip upon what is going on with the cam and lifter to begin with.
  a .842 diameter solid lifter on a 230 duration @ .050 will lift a valve with a 1.5 rocker to .480 lift . use the amc .904 lifter same length as the gm just bigger in diameter with same cam and rocker net valve lift is .515   its worth getting a grip on


Your grip is not what you think it is Pank, Unless the first set of numbers you punched in has the the contact point off the edge of the lifter (which is unrealistic because the cam and lifters will be junk in seconds when started) it just cant be that a larger lifter gives more lift than a smaller one with the same cam.  I said Optimum, not some BS numbers punched in a computer program so as to try to prove yourself right.  I am not going to argue a point a 10 year old can understand without a computer program,,, believe what ever you wish.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mlpankey Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 8:20pm

the larger diameter decreases presure angle gives the designer a opportunity to design a more intense flank along  with  the increase the duration and lift the diameter increase does by its self. i can provide technical bulletins from leading cam designers butch to prove you wrong if you wish. or just ask garry  since your so wanting to prove me wrong. another whos joined the peanut gallery. 

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SteveM C/IL View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SteveM C/IL Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 8:36pm
WTF!  Same cam? The tippy top of the lobe is at the same height no matter how big a drum you set on it.NO? How then can it give more lift than it has? Don't mean to talk over your head with technical jargon like "tippy top". Help me understand your logic. Large dia will accellerate faster on same lobe but raise higher? HUH?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Butch(OH) Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 8:45pm
Originally posted by SteveM C/IL SteveM C/IL wrote:

WTF!  Same cam? HUH?


No different cam this time, same cam before, or was it something else?  Must be some bad 'shine in that part of the world, LOL




Edited by Butch(OH) - 07 Feb 2012 at 8:49pm
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  Large diameter will
increase the duration
        IMHO
         B:-)    Dnoym
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mlpankey Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 9:21pm
Originally posted by SteveM C/IL SteveM C/IL wrote:



WTF!  Same cam? The tippy top of the lobe is at the same height no matter how big a drum you set on it.NO? How then can it give more lift than it has? Don't mean to talk over your head with technical jargon like "tippy top". Help me understand your logic. Large dia will accellerate faster on same lobe but raise higher? HUH?
take a cam use a standard 842 lifter then run a pencil eraser over the cam lobe. The diameter lifter change will affect e rise.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mark vaughn Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 9:23pm
Do you tractor pull pankey? If so i hope its AC power. I saw the engine you posted pictures  of and it was pretty nice. It takes alot of time to put sleeves in a block like that!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian Jasper co. Ia Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 9:35pm
Originally posted by mlpankey mlpankey wrote:

Originally posted by Butch(OH) Butch(OH) wrote:

Since those with sense are going to talk about it I will add my two cents.
If I remember the question correctly he asked what was to gain from increasing the diameter of the lifter and the answer is nothing given that the cam is at optimum and the condition Brian mentioned is met. If a cam profile is not at optimum and cannot be ground as desired due to the ramp being at the edge of the lifter then yes, gains could be had by increasing the diameter of the lifter. The cam grinder can reduce the base circle to accomplish the same thing. All in all it's one of those things that just plain isnt worth a whole lot of chat unless a person cant get a grip upon what is going on with the cam and lifter to begin with.
  a .842 diameter solid lifter on a 230 duration @ .050 will lift a valve with a 1.5 rocker to .480 lift . use the amc .904 lifter same length as the gm just bigger in diameter with same cam and rocker net valve lift is .515   its worth getting a grip on . The lifter diameter is also taken into account whe a cam designer is figuring the intesity of the flank for another term pressure angle. Anology we back into a parking spot with a 14 inch tired toyota corolla when we roll up against it we drop the clutch car lunges hard up against it and dies due to the small diameter tires pressure angle. Now we back our 16.9/38 tired 40 hp tractor up against it at a idle drop clutch and where over the curb and in the space behind the curb due to the larger tire diameter having a less pressure angle .
Mitch, correct me if I'm wrong, but in the most simple terms what you're saying is in your first example with the small diameter lifter that .480 lift is the maximum the lobe and lifter combo will tolerate before damage. The larger lifter diameter can either lift higher or faster due to the larger contact patch between the cam and lifter. Just like the tractor tire vs car tire. All things being equal, the tractor tire will transfer more energy before spinning out vs. the car tire because the contact patch is larger.
In simple terms, larger contact area, more load carrying (valve lift/spring pressure).
 
"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian Jasper co. Ia Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2012 at 9:54pm
Ok, so now I'm picturing that cam in my head, just like the tire, a lobe with the same dimensions on a larger diameter shaft, (that's called base circle right) would open and close the valves faster wouldn't it?
"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SteveM C/IL Quote  Post ReplyReply Direct Link To This Post Posted: 08 Feb 2012 at 12:14am
Originally posted by Butch(OH) Butch(OH) wrote:

Originally posted by SteveM C/IL SteveM C/IL wrote:

WTF!  Same cam? HUH?


No different cam this time, same cam before, or was it something else?  Must be some bad 'shine in that part of the world, LOL


I'm new to this quoting thing.....Butch your puncuation or lack there of has me even more confused.  Is it " No(comma) different cam this time". Or...." No different cam(meaning same) this time"?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mrbill69 Quote  Post ReplyReply Direct Link To This Post Posted: 08 Feb 2012 at 7:17am
A larger diameter lifter will do nothing on the same cam profile. But it will allow the cam grinder to grind a slightly more aggressive profile (ie: faster lift and close rates) without the edge of the lifter contacting the lobe. Not really something that a tractor engine would benefit from.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Butch(OH) Quote  Post ReplyReply Direct Link To This Post Posted: 08 Feb 2012 at 7:26am
Originally posted by SteveM C/IL SteveM C/IL wrote:

Originally posted by Butch(OH) Butch(OH) wrote:

Originally posted by SteveM C/IL SteveM C/IL wrote:

WTF!  Same cam? HUH?


No different cam this time, same cam before, or was it something else?  Must be some bad 'shine in that part of the world, LOL


I'm new to this quoting thing.....Butch your puncuation or lack there of has me even more confused.  Is it " No(comma) different cam this time". Or...." No different cam(meaning same) this time"?


Sorry Steve and everyone else I confused. Mitch deleted two posts that were a pretty outlandish read. The were only up for a couple minutes last night and you probably didn't get a chance to read them before he withdrew them. I posted that before he withdrew them and it was a tongue in cheek poke at his dodging back and forth on the base line facts.

I forget that people here don't know my personality and cant see my face when posting, apologies offered and following explanation offered,

We started out by trying to make the point that given any certain USABLE cam profile /lifter combination that changing lifter to a larger diameter only (again, replete, capitalized ONLY) isn't going to make one little bitty difference in the duration or lift at the valve. He countered that with a post that states a larger lifter would give "X" amount of extra lift based on computer generated numbers. Now I don't need a computer program nor does anyone else with a thinking cap on to know that is BS. I don't care of you set a 55 gallon drum on  top of that cam lobe it isn't going to lift it one little itty bitty bit more than a  sewing needle.  His latest post says I am FOS because the cam grinders say if you enlarge the base circle and lifter diameter it will give the grinder some freedom in is ramps which is absolutely true but not what I am contesting.

If this subject must be turned into rocket science we must separate lift, duration and ramp or acceleration of the valve from seat to open.
Lift and total duration is pretty easy to understand and I wont waste space here to explain them,
 Ramp or acceleration is not as easy but damned important as getting the valve open and closed quickly without creating forces that will destroy the valve train is the goal. I think this is what Mitch is calling "flank" but I don't know? The grinder must also keep the point of contact within the face of the lifter diameter. If it goes past the edge bad things happen quickly. The faster the cam ramps up the further the point of contact travels away from the center of the lifter. This is why a larger lifter gives some freedom to how the cam is ground, it allows for the pint of contact to be further away from the center-line of the lifter. Another way they do it is to reduce the base circle of the cam. So why not just get some huge lifters and smack them like a baseball bat with an aggressive ramp and be happy? Because there are other factors involved too, mainly valve train weights and acceleration rates. You can start and stop that valve train so quickly it destroys itself as fast as you can install new springs, push rods and rockers. Heavy parts and fast accelerations and decelerations  require heavier springs to stay away from valve train destroying float at hi RPMs.

Cam and valve train design is pretty interesting when talked about intelligently. It just isnt as simple as big lifters cure all evils and I guess that is my point off all this rambling.


Edited by Butch(OH) - 08 Feb 2012 at 7:37am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lynn Marshall Quote  Post ReplyReply Direct Link To This Post Posted: 08 Feb 2012 at 9:11am
ALL this tech talk makes me think of this.  [TUBE]http://youtu.be/rLDgQg6bq7o[/TUBE]
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rod B Quote  Post ReplyReply Direct Link To This Post Posted: 08 Feb 2012 at 9:12am
Originally posted by mark vaughn mark vaughn wrote:

Do you tractor pull pankey? If so i hope its AC power. I saw the engine you posted pictures  of and it was pretty nice. It takes alot of time to put sleeves in a block like that!
 
 
Mark.  Don't let him fool you too.  He has tried pulling but his stuff never runs and blows up after 5 hooks.  Though he will lie, dog around and try to make us think otherwise.  It gets easy to see who knows what and who gets information from the latest magazine at the gas station.
 
Butch hit that nail right on the head.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mark vaughn Quote  Post ReplyReply Direct Link To This Post Posted: 08 Feb 2012 at 6:56pm
Disassembled my coustmers other ex NASCAR DODGE engine today. The last track it ran at was Bristol. It also has a flat tappet solid lift cam in it because that is NASCAR rules. This camshaft has a hugh 1.542 base circle and the lifter dia. is .875. the cam lobe rise is .382 x rocker ratio of 2.230 = .851 valve lift at 0 valve lash. The spring pressure on these engines do rival roller cam spring pressures. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mlpankey Quote  Post ReplyReply Direct Link To This Post Posted: 08 Feb 2012 at 7:29pm
Nascar definitely knows the advantage of larger base circles. wondering though with it being a dodge why the 904lifter wasn't used. Yes I have pulled tractors since 2000 and your right the bore and sleeves takes the same time that it would take to put 4 60 over big blocks out the door.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SteveM C/IL Quote  Post ReplyReply Direct Link To This Post Posted: 08 Feb 2012 at 11:09pm
Got it Butch.I think I know you well enough to not misunderstand yer speak but I must have missed the afore mentioned post so that's why I couldn't get what you were saying. You are correct on the whole picture about cams. I was reading a cam designers website and he went so far as to say that you can't accuratley copy/transfer a profile even with the best machines.Had a small explanation about lobe design/creation and after that it kinda made sense. Somethings are not as they seem. This may be one? Anyway,thanks for the update.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stan IL&TN Quote  Post ReplyReply Direct Link To This Post Posted: 09 Feb 2012 at 7:29am
Originally posted by Lynn Marshall Lynn Marshall wrote:

ALL this tech talk makes me think of this. 
 
I have several farthing bearings and a coupe of dingle arms if anyones interested?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Butch(OH) Quote  Post ReplyReply Direct Link To This Post Posted: 09 Feb 2012 at 7:38am
Originally posted by mlpankey mlpankey wrote:

wondering though with it being a dodge why the 904lifter wasn't used. .
Because they understand the entire picture not a tiny piece of it or they wouldn't be going roundy round on a NASCAR track for very long.
With the profile used the point of contact appearantly stays within the confines of a .875 diameter and as some have been trying to point out there is nothing to gain from going larger than required. However are minuses to going larger than need be the biggest being valve train weight.  Other smaller factors are increased friction, weakening of the block.  I take it that a 904 lifter is standard for that style of Mopar engine? If so and for them to go to all the trouble to use a smaller than std lifter???  Why hows come??  maybe they wanted to run last place?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mlpankey Quote  Post ReplyReply Direct Link To This Post Posted: 09 Feb 2012 at 12:48pm

The bigger the lifter the more agressive the flank can be designed before exceeding the pressure angle that tends to cock a lifter in the bore . .904 is mopars lifter size . without knowing the engine and seeing the cam why they went to a smaller lifter one could only speculate. However its been proven by cam grinders that will grind the cam flank for the 904 larger diameter lifters  a horsepower increase can be found. In crane cams technical data their roller cam is desinged for a .750 wheel minimum and can be ran with a .800 wheel wich they recomend . In the tech.data they also give the duration change from the bigger lifter at each .100 of valve lift.



Edited by mlpankey - 09 Feb 2012 at 12:49pm
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