A/Fuel Engine Combination

Hey everyone,

I am putting together an A/Fuel dragster. I have a lot Top Fuel Parts. I was thinking of using a TFX fuel block and putting a .250 smaller bore in it instead of the 4.187 bore so I can keep the 4.500 stroke cranks that TF runs. This way I can use the blocks, cranks, and rods. This would make it a 3.937 bore, and that would come out to be a 438 inch engine. Does anyone have any thoughts on why this would not be a good idea for an A/Fuel Combination?

Thanks,

JP Gutierrez
Gutierrez Brothers Racing

 

i hate to ruin your plan but the fat head style head needs a min. 4.250 bore.... they recomend a 4.310 bore.... but 4.250 is the min...Mike

 

Don't know the intake valve angle of a fat head but if you're running a fuel head, the intake valve relief in the top of a 4.187 sleeve is pretty severe already, but you're really only adding another .125" to the ID of the sleeve. Valve shrouding would be an issue at low lift but because of the angle, anything above .200" lift approx., flow should have a clear shot to the cylinder. Another possible benefit, small bore=quicker flame travel, since nitro's slow burning, seems like it might be a little smoother power stroke (just guessing). Would definitely be a severe mismatch from top of sleeve to combustion chamber though, could create hotspots. One real advantage, sleeves would stay perfectly round with that kind of thickness. Interesting idea.

 

A-Fuel Parts

Sell your stuff + hook up with Nitro link or Larry Miersh. He is selling A-Fuel stuff. Run Big Bore short stroke stuff. !/2 short or std. deck You will need to find a injected intake. You can get some -5 fathead stuff @ a good price since most are running the new heads. Good luck Don