manifold

was wondering what you guys suggest as far as a manifold for a pulling engine thats around 315 ci.

I'm just wondering exhaust or intake? What engine AC 301 ? Wd ?

Here's the quick and dirty on the manifolds for these things.  The carb neck to manifold junction is nothing more than a T shape.  So stand there with your arms out in a T shape..... you need to radius the armpits.  This isn't so simple.  I weld the corners with many passes and build it out near the carb flange, I fill that area because when I grind the inside it's going to get wide and it's going to bread through the original casting.

Next I clamp the manifold in a milling machine and I cut 2 1" holes in the back side (engine side) in the right location of the manifold body on each side of the carb neck.  This hole will allow me to put a 1" round wheel on an extended die grinder to fully radius the corners.  I also drill and tap the front of the manifold where the runners go into the head, there's a dimple there from the casting process, that's where I drill for a 1/4" bolt, this bolt is simply for a mechanical bond for epoxy.  I also drill straight up from the carb through the top of the manifold, centered in the carb throat and tap for another bolt to serve as a mechanical bond.

Now I grind the throat and taper  it, I start the taper and radius into each runner.  Then I work through the back side holes I cut to finish that radius. 

Then I grind the floor of the round portion that mates to the head in a teardrop shape, from the head mating surface I taper down and flatten the bottom of the round runner and roll a radius around that corner. 

Now put the 3 bolts in those holes  that I drilled and tapped.  I mix a epoxy called "Splash Zone"  By wetting my fingers it does not stick to them and I can kneed it around and work it like play dough.  I build a wedge above the carb, centered in the throat to take up the volume that increased up there and this gives the air some direction to go as well as helps the robbing when the engine pulses front to back, back to front in the breathing cycle. 

Then I put epoxy on the top corners of the runners that go into the head to hold the air on the floor, tip the manifold 45 degrees and build a wedge in the top corners. 

When I say wedge, they are not straight like an inverted V but they are a radius shape.

Then fill the 1" holes with some expansion plugs flush with the inside of the manifold and tac weld them.

Stock manifold will flow 115 CFM if I pull air through a runner, cap off the other runner and put a radiused inlet on the carb flange.  If I simply die grind the corners a bit in a few minutes, figure 140 CFM.  If I work at it a while and do everything I can do without cutting more access holes they will flow about 180 CFM.  If I really work at it and cut the access holes and build the radiuses, the divider, fill the corners, etc.  225-230 CFM.  Yes, they double in flow and I didn't increase the runner size.  I just made the inlets to each stage as efficient as I can in the manifold and fill the corers, air hates to expand.  It's easy to keep it moving and make gentle corners as long as it can't expand.  By filling the corners I can keep a higher velocity air stream attached to the floor.  Once it becomes detached it tumbles and gets confused. 

Try running down a set of spiral staircases, you can't go very fast, but if it's narrow and you have a railing to keep you attached, you can go twice as fast.

Does anyone port allis 226 manifolds? I would be interested in having one
done or buying one.

WI50, did my manifold last winter. I ported it myself when he checked it was putting out 170 cfm, when Marty got done with it, it put out 220 cfm. I gained 20 lbs of cylinder pressure. I have mine off right know I can send u some pics of it. Pm me with cell number.