wc pulling advise

I have found a set of 15.5-38 tires and a set of 16-38 wheels. I am pulling in a 3 mph.class, should I even try to pull without lower gears? I know I will be idling until I get some slip. Or, should I put more into the engine,like stroking it out to 5 or 5.5 and run stock gearing?The engine is basicly a d17 build with some head improvments, I will pull in the 3500-4000 class. Thanks, JM

My advice in a 3 mph class is WD45 type horsepower (stock) is sufficient as long as you are running 28 inch rubber.  And I would run 28 inch rubber, here's why:  it is much easier to find traction with short tires (23 degree, 26 vs. 28 inch, old vs. new tires, 13.6 vs 14.9 etc.) than it is to find the horsepower to make those big wheels turn.  Sure, there's gearing changes (D17 diesel type) andstroker motors etc., but there is a lot to be said about the Allis set-up from the factory.  3mph is slow, and I can make 28 inch rubber stick to a track.  I've recently switched to a 13.6 from a 14.9 (unheard of) and have had good results with a wide rim (no wider than tire) to get that tire to work.  My experience with the short tire set-up began when I got my rear end handed to me by a WC with 26 inch combine rims and 14.9 /26 rubber.  Hope this helps, but as always it is just a good hearted suggestion.  When I'm suffering in the traction department, it is almost ALWAYS hitch height and length that was my mistake...not the tire size's disadvantage.  Good luck and have fun.