Just came from Dyno, 71 BB
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 923
Likes: 4
From: Austin Tx
Just came from Dyno, 71 BB
Just came from the dyno. 71 BB with LS6 pistons, heads and intake, Holley 800, unknown cam from previous owner. What do these numbers tell you about the came that is in there, and would going with a LS 6 nostalgia solid cam kit make a big difference. When I bought the car it and had a lot of "off the shelf" parts so who knows what cam is in there...
peak rear wheel HP 349.28 @ 4620 rpm
peak rear wheel tq 460.89 @ 3387 rpm
AFR 13.237 @ 4129 rpm
peak rear wheel HP 349.28 @ 4620 rpm
peak rear wheel tq 460.89 @ 3387 rpm
AFR 13.237 @ 4129 rpm
Melting Slicks
Joined: Jan 2003
Posts: 2,877
Likes: 13
From: Doha
St. Jude Donor '08
what kind of transmission do you have?, a TH400 will consume much more HP/TQ than a 4 sp., it could be as much as 30%, so in theory you could have a 450 HP engine under the hood if its a TH400.
Drifting
Joined: Oct 2010
Posts: 1,972
Likes: 6
From: Chester Virginia
pretty good
as rear wheel dyno numbers those are pretty good numbers. That means your sae gross engine on a stand number by gm would be in the low 400 hp's and with that kind of torque of 460 probably around 450 hp. Not bad for that vintage motor. If you want more there are guys here who can tell you how to get it but if you have a 3:36-3:73 rear end and four or five speed that car ought to have a fair amount of punch to it with just proper tuning.
If I had my choice I would have had a big block instead of an l48 5.7 L small block but then I bought a tbss with a 2008 ls2 in it and a 4:10 rear end so get my kicks with its punch and drive the vette for road drives where it shines too.
Lance
If I had my choice I would have had a big block instead of an l48 5.7 L small block but then I bought a tbss with a 2008 ls2 in it and a 4:10 rear end so get my kicks with its punch and drive the vette for road drives where it shines too.
Lance
Burning Brakes
Joined: Jun 2010
Posts: 1,165
Likes: 93
From: Bellmore NY
All things considered those are pretty good numbers, however the power is made at fairly low rpms.
Could they be improved by a cam swap? Of course, however you never mentioned if you were using headers or stock exhaust manifolds, or if this was an option to do over a cam swap. Your intake manifold is also a limiting factor, and you never mentioned what total timing was and or how old the valve springs are.
Depending on what cam is actually in there, with all of the above variables, the LS6 cam may not give you an improvement. Aside from that, there are many better choices today than the factory grinds that were available 40 years ago.
Could they be improved by a cam swap? Of course, however you never mentioned if you were using headers or stock exhaust manifolds, or if this was an option to do over a cam swap. Your intake manifold is also a limiting factor, and you never mentioned what total timing was and or how old the valve springs are.
Depending on what cam is actually in there, with all of the above variables, the LS6 cam may not give you an improvement. Aside from that, there are many better choices today than the factory grinds that were available 40 years ago.
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 923
Likes: 4
From: Austin Tx
Running hedman sidepipe headers dumping into 3 in pipes (tucked under factory 69 covers), M21 4 speed with 3.55 gears, 36 deg total timing, valve springs are at least 10 years old, but could be much older (already installed when I bought the heads used).
Last edited by Gage; Mar 19, 2012 at 09:17 AM.
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 923
Likes: 4
From: Austin Tx
No, he wouldn't have known anyway, the guy was not a vette guy by any stretch. I installed the Ls6 heads myself and just set the lash by the only method I know...I thought valve lash was either right or wrong, nothing in between. Where in the Lehigh valley are you?? God's country up there!!!
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Melting Slicks
Joined: May 2001
Posts: 2,131
Likes: 4
From: May help you? You can sure as hell try!
It appears that you are running a bit lean as well. 12.5:1 is a pretty good ballpark figure for LBT (leanest for best torque) for most engines. Torque drops off quite sharply when lean of LBT. It is almost always better to be on the rich side--for both power and for keeping exhaust temperature within reason. Do you have the complete torque vs. engine rpm as well as AFR vs. engine rpm curves?
email them to me, Greg, if you have them or post them.
It does seem as if your peak power number is occurring at a rather low RPM which tends to indicate that the engine's not breathing at the higher RPMs or the AFR is leaning out or both.
email them to me, Greg, if you have them or post them.
It does seem as if your peak power number is occurring at a rather low RPM which tends to indicate that the engine's not breathing at the higher RPMs or the AFR is leaning out or both.
Melting Slicks
Joined: Aug 2008
Posts: 2,200
Likes: 3
From: Lehigh county Pennsylvania
No, he wouldn't have known anyway, the guy was not a vette guy by any stretch. I installed the Ls6 heads myself and just set the lash by the only method I know...I thought valve lash was either right or wrong, nothing in between. Where in the Lehigh valley are you?? God's country up there!!!
Potter County Pennsylvania is known as God's Country. Where I live is known as the god forsaken craphole.
I live in that part of the Lehigh Valley that is now know as New Jersey West, what with all the Joisey's and Long Islanders who move in.
