GOSFAST
Jun 11th, 06, 10:34 AM
This post is "aimed" at the many up here that follow HP/Torque numbers with respect to "stock" and "stock appearing" units. The unit was first tested with our carb and headers and came off the dyno with 510 HP @ 5700 RPM and 500 Ft.Lbs. Torque @ 3900 RPM. This was with open headers. We were happy with those results. Using the customers carb and our headers it did 495 HP/500 Torque, same RPM's.
After installing his cast iron factory exhaust manifolds and leaving his carb in place, our final "as-delivered" numbers were 464 HP @ 5800 RPM and 484 Ft.Lbs. @ 4200 RPM. The exhaust's here are the "restrictor".
What we've concluded from this test on this particular unit is the fact that the stock "square-port" intake, #3963569, IS capable of producing past the 500 HP number, unlike the recent LS-5 "oval-port" test where the "open-headers" made absolutely no HP difference. We estimate we could possibly get 550 HP through this particular intake. We have to make certain we don't have a vacuum issue for accessories! A slightly larger cam along with headers would have made a significant HP increase.
This is a "pump-gas" unit that runs fine on 93. The specs are 10:1 C.R., 238/248 @ .050" x .550"/.570" x 112L/S. This is a solid lifter unit with a set of "Probe" pistons, a +.250 long rod, and stock valve sizes with .375" stems.
The #291 heads, in at 99 cc's did receive a decent amount of "bowl/runner" work, but NOT a "full-port". We felt that extensive cylinder head work would be wasted using the stock intake setup! It's topped off with a set Comp Cams #1320 rockers and will end up with the stock valve covers in place.
It was destined to be at Englishtown for the "Fast" race today but obviously didn't make it on time. It posed no problem however. It's headed into a
"numbers matching" 1970 Chevelle.
(Edit/add) I just want to add here we couldn't "cheat" on the size with this unit, at the races it'll get a "pump-up". It's a stock stroke (4.000") unit according to the rules.
Below is a shot as it was delivered. The valve covers/breathers are for test only! Thanks, Gary in N.Y.
P.S. When you are ABSOLUTELY "locked-in" to stock appearances you will find that the HP numbers are difficult to deliver. This unit is in "contrast" to the 396 pump-gas one a few months back, using the "Winters" (open-chamber) heads, 10.5:1 C.R., a step or two up on the solid lifter cam, and an old "Torker" intake, that was delivered with over 500HP on 93! That was with a "Holley" and open headers.
http://i16.photobucket.com/albums/b28/GOSFAST/PES%20Engines/th_LS-6Delivered.jpg (http://i16.photobucket.com/albums/b28/GOSFAST/PES%20Engines/LS-6Delivered.jpg)
After installing his cast iron factory exhaust manifolds and leaving his carb in place, our final "as-delivered" numbers were 464 HP @ 5800 RPM and 484 Ft.Lbs. @ 4200 RPM. The exhaust's here are the "restrictor".
What we've concluded from this test on this particular unit is the fact that the stock "square-port" intake, #3963569, IS capable of producing past the 500 HP number, unlike the recent LS-5 "oval-port" test where the "open-headers" made absolutely no HP difference. We estimate we could possibly get 550 HP through this particular intake. We have to make certain we don't have a vacuum issue for accessories! A slightly larger cam along with headers would have made a significant HP increase.
This is a "pump-gas" unit that runs fine on 93. The specs are 10:1 C.R., 238/248 @ .050" x .550"/.570" x 112L/S. This is a solid lifter unit with a set of "Probe" pistons, a +.250 long rod, and stock valve sizes with .375" stems.
The #291 heads, in at 99 cc's did receive a decent amount of "bowl/runner" work, but NOT a "full-port". We felt that extensive cylinder head work would be wasted using the stock intake setup! It's topped off with a set Comp Cams #1320 rockers and will end up with the stock valve covers in place.
It was destined to be at Englishtown for the "Fast" race today but obviously didn't make it on time. It posed no problem however. It's headed into a
"numbers matching" 1970 Chevelle.
(Edit/add) I just want to add here we couldn't "cheat" on the size with this unit, at the races it'll get a "pump-up". It's a stock stroke (4.000") unit according to the rules.
Below is a shot as it was delivered. The valve covers/breathers are for test only! Thanks, Gary in N.Y.
P.S. When you are ABSOLUTELY "locked-in" to stock appearances you will find that the HP numbers are difficult to deliver. This unit is in "contrast" to the 396 pump-gas one a few months back, using the "Winters" (open-chamber) heads, 10.5:1 C.R., a step or two up on the solid lifter cam, and an old "Torker" intake, that was delivered with over 500HP on 93! That was with a "Holley" and open headers.
http://i16.photobucket.com/albums/b28/GOSFAST/PES%20Engines/th_LS-6Delivered.jpg (http://i16.photobucket.com/albums/b28/GOSFAST/PES%20Engines/LS-6Delivered.jpg)