RPMs with Fuel Heads?

What kind of RPM are you guys running on fuel heads? Still new to all of this, and am trying to get some context. I understand that the pistons are heavier in the fuel head engines, thus less RPM potential, but less than what? and how much less?

-Scouder

 

Rpm

I am using fatheads, and all my A-Fuel parts in my Top dragster, Kebelco shift @ 8000. Pistons are 814 gms. pins are 328 gms with fuel rods that I sent back to get the beams machined. It revs very easy + no problems. I do check bearing rods + mains often.. especially the thrust because I run a Powerglide. But just to let you know I run these because I had 3 sets of everything, + I couldn't sell them @ a fair price. I will leave it @ that. Run what you got. Good Luck Don

 

The last few seasons we have been running aj stage II fuel heads. I always shifted at 8000 rpm have had very good luck 4 teens in 1/8 mile pro mod car but this year looking for a little more performance and was told to rev it more and it would perform better. so started reving to 8800. Did not perform any better at all just harder on parts. so I felt that was about all they were good for but what do I know?? switching to muscle heads for next year need to be in 4 flat range

 

revving the motor

I have run big chambered heads like the fuel style heads and smaller chambered heads like the currently popular top alcohol combinations. Certainly the big chambered heads need a much taller piston dome to achieve a decent compression ratio- that makes for a heavier piston. But I think the ability to rev the motor also has a lot to do with the stroke of the crankshaft. The longer the arm the slower the motor turns. My current motor only has a 4.125 stroke. That is compared to the big chambered motors I ran with a 4.500 stroke. It is sort of a balancing act between piston weight vs crankshaft stroke and the most important factor- the thickness of your wallet. Of course most of this truly depends on what you are trying to do- NHRA national event competition vs something a little less competitive?
Dave Germain

 

usually the older fuel heads have either a 2.375 or 2.400 intake valve . that and the port size and angles don't make much more power over 8500 rpm. I ran them for years.

 

thats about what i was told when i got my first hemi had brad fuel heads shift around 8400-8800 but 8800 was the max they told me because i didnt know shit about a hemi back then

 

jim did you get my voice message I sent to you on your cell

 

i tried to call you back

 

Scouder..

We've been running the early brad deal for 15 years and over that time we have had to make it work against the fat heads (and other heads). Roots, screw, 2 mag 4's, 1 mag 44, ....etc.

For your purpose there is no need to shift it any higher than the rpm ranges listed above. With a few mods you can take them much higher though.

Kris shifts "the ghost" around 9200-9600-9800 rpm depending on the track and who's in the other lane. (with a 4.5" crank).

And has stepped off the throttle a time or two when he had to short shift it and just ran out of engine (10,000 rpm) before running out of race track.

They can go up there as long as you don't have to stay there too long.

Lesson: "be aggressive but be smart"

Our early BAE piston, pin, button, and ring combo is lighter than our new "Fat Head" piston combo. Be careful to seperate what's normal...and what's possible....

Your mileage may vary....

Be well...and stop in any time if you get over this way....

Kevin Hool

 

If I get over in your neighborhood you can bet I'll stop and meet you guys. Also, If you are still planning on testing in Vegas in Feb and need an extra pair of hands let me know. I'll be looking for a reason to get out of the snow by then!

-Scouder