hp estimates
Thread Starter
Racer
Joined: Mar 2005
Posts: 393
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From: Dallas, TX
hp estimates
i have a regular old 1970 LT-1 (hiding in a 1977 t-top vette), factory 370hp 380tq, ive got crane gold race roller rockers and side pipes with a mildly ported and shaved heads, bored .030 over, 4.10 rear gears and a BW 4spd, any thoughts on what kinda a power im putting down, i can guess but it probably wouldnt be very accurate because my expirence with corvettes is limited at best. also ive thought about gettings some AFR heads and a better intake, any advice in that department if greatly appreciated.
-alex
-alex
Drifting
Joined: Jun 2005
Posts: 1,950
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From: Chino Hills CA
I didn't know you could run roller rockers on a solid lifter motor, I'll have to remember that. Anyway you didn't say if you were running headers, which should be a must with that combination, as well as how much your heads were milled. Assuming around 10.5 to 1 compression, you ought to be getting 400-425 at the crank, maybe 375 at the wheels. With a 4.10 rear end, you should be able to get sideways in the first 3 gears, must be miserable on the freeway though, 70 gotta be at least 3600 rpm.
Pro
Joined: Jan 2002
Posts: 624
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From: Marietta ga
Originally Posted by lowbuck72
I didn't know you could run roller rockers on a solid lifter motor, I'll have to remember that. Anyway you didn't say if you were running headers, which should be a must with that combination, as well as how much your heads were milled. Assuming around 10.5 to 1 compression, you ought to be getting 400-425 at the crank, maybe 375 at the wheels. With a 4.10 rear end, you should be able to get sideways in the first 3 gears, must be miserable on the freeway though, 70 gotta be at least 3600 rpm.
Thread Starter
Racer
Joined: Mar 2005
Posts: 393
Likes: 3
From: Dallas, TX
the engine had some 13:1 cr pistons with all blown rings but have been replaced with 10.6:1 cr speed pro forged (the heads were shaved down a bit so the cr is probably closer to 10.8-10.9:1), really the only mods are the roller rockers crane claims add up to 25hp(which needed taller valve covers), headers, sidepipes(gonna get the hooker hi-po ones from summit soon), 7qt oil pan and a melling high volume pump, and the rotating assembly lost some weight, it had gm pink rods but now has eagle forged i-beam, im pretty sure it would rev to 9000 rpms if i put my foot to the floor. in any event your imput is greatly appericiated.
-alex
70mph=3500ish Rpms, with belt slip, uhg, but it sure does get there really fast.
oh yeah shes bored .030 over, so its a 355.
-alex
70mph=3500ish Rpms, with belt slip, uhg, but it sure does get there really fast.
oh yeah shes bored .030 over, so its a 355.
Last edited by 1fastC3; Mar 31, 2006 at 09:55 AM.
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If you are 10.8 or so then you likely have more than the average LT-1 had from the factory. Those 11.0 numbers were highly optimistic...more like 10.5 or so at best.
The rockers won't really add much of anything unless they are 1.6 ratio..that might help a few more ponies. Maybe 5 hp at best with regular 1.5's. But they do add reliability once you start abusing things.
Head porting? Who knows,,,maybe 20-25HP. Depends on how good it was. Could be 40+ if someone went crazy. What porting really helps with is it hangs on longer after peak power. That really helps performance.
The LT-1 cam is a great street cam and with 1.6 rockers will really work well.
My gut tells me we are in the 375-410 hp range....so maybe 300-320 RWHP? Easy way to find out...let's stick her on a chassis dyno...you can usually get three pulls for $50-$75.
A nice set of heads would really wake it up.
JIM
The rockers won't really add much of anything unless they are 1.6 ratio..that might help a few more ponies. Maybe 5 hp at best with regular 1.5's. But they do add reliability once you start abusing things.
Head porting? Who knows,,,maybe 20-25HP. Depends on how good it was. Could be 40+ if someone went crazy. What porting really helps with is it hangs on longer after peak power. That really helps performance.
The LT-1 cam is a great street cam and with 1.6 rockers will really work well.
My gut tells me we are in the 375-410 hp range....so maybe 300-320 RWHP? Easy way to find out...let's stick her on a chassis dyno...you can usually get three pulls for $50-$75.
A nice set of heads would really wake it up.
JIM
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Originally Posted by lowbuck72
That was the old 370 gross, would only be about 300 net. Also 9000 rpm seems just a bit optimistic.