Thread: new top end and no more power???

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Hey Listen to Dave and Tec, These are two guys that don't B.S. and really know thier stuff. Kurt

Elevation makes a big difference.....When we left the flat lands and went to run at Bandemere in Denver the car was much, much slower at 5,000 ft.

My experience has been to build a street engine concentrating on getting all the right parts to build TORQUE and let the horsepower fall where it will... Heavy (over 2500 lbs) cars at low rpm (under 6500) on the street need big torque numbers to be movers instead of just a pooch.... basic Physics wins out every time......

Originally Posted by vara4

Hey Listen to Dave and Tec, These are two guys that don't B.S. and really know thier stuff. Kurt

Thanks Kurt, but I'm certainly not a chebbie engine guy, suspension and "creative body work" is more my stuff... Tech and Pat are both very, very sharp on engine internals, cam and head requirements.......

Hey Dave; My cam is at 6500rpm's with 12 to 1 comp. and only weights
2000pds. It goes to my buddies shop this week, he's gonna weld in my
new tail light section and fix the rusted holes over the wheel wells.
Then he is gonna take the hole body down to bare metal fix all the dings
and primmer it. He was gonna paint it but I told him I'm not ready for that
yet! Anyway I bread boxers and he wants two pups, so we made a deal.
Kurt

i also heard that you can run higher compression with aluminum heads because they dissipate heat quicker....so technically they lower your compression ratio????? and if that's the case, along with elevation losses....i'm basically screwed for performance aren't i? unless i build a new higher compression bottom end. in which case i would do a stroker. what stroke would you guys recommend? i could do a 388 or a 401 with my other block, also i have machine shop friends that would clearance the block for the 3.875 in stroke for me. what compression ratio would you guys recommend on pump gas (91 octane)? 10.5:1? i plan to stay up here at about 4500 ft for a while, but even if i did go to the bay area or something, would their 93 octane gas cancel out the elevation problem? i have another friend with a 496 BB with aluminum heads that seems to be running fine with about a 10.8:1 CR. and that's not my equation to figure it out, that's what the machine shop said when they built it for him.

i was thinking if i just put a smaller cam in this combination, won't my heads be way too big for the rest of the motor then?