1971 Buick 455 GS F/SA G/SA Build

[Steve Lackey]

Have you tried any header tuning while on the dyno? These engines really benefit from the exhaust scavenging. That is why the original Stage 2 heads were so effective.

[chris ok]

Congrats on your hard work paying off. Nice power. Small valve low compression engine. I look forward to hearing about testing now.
Chris

[HP HUNTER]

Originally Posted by chris ok

Congrats on your hard work paying off. Nice power. Small valve low compression engine. I look forward to hearing about testing now.
Chris

Thanks, I have tested Aug 19. In F/SA trim I ran 11.40 with zero tuning at Pueblo Colorado 4800 feet elevation, 25.10 baro, 7240 DA, .9508 correction, running the Turbo 400 with 4.10 gears. My next change is testing different carbs, a metric trans and 4.30 gears along with a rear end redesign. I really wish I had the time to really get after this combination I think it could really run.

[Mark Yacavone]

Originally Posted by HP HUNTER

Thanks, I have tested Aug 19. In F/SA trim I ran 11.40 with zero tuning at Pueblo Colorado 4800 feet elevation, 25.10 baro, 7240 DA, .9508 correction, running the Turbo 400 with 4.10 gears. My next change is testing different carbs, a metric trans and 4.30 gears along with a rear end redesign. I really wish I had the time to really get after this combination I think it could really run.

You ran 11.40 actual et? What is the index at that altitude then?
Call me..Can't find your number ..Have an unrelated question for you.
602-769-0346

[HP HUNTER]

Originally Posted by Mark Yacavone

You ran 11.40 actual et? What is the index at that altitude then?
Call me..Can't find your number ..Have an unrelated question for you.
602-769-0346

I don't know the index in F for Pueblo, although the NHRA correction is .9508. 11.4 X .9508 = 10.84 not earth shattering.....but I'am just getting started. Stay tuned.

[Dwight Southerland]

11.40 / .9508 = 11.99

[JRyan]

Dwight,

Hunter was taking his run back to sea level with the .9508 factor. That's what that factor does. You divided instead of multiplying. As an example, the factored Index for Pueblo, 12.46 x .9508 gives you the sea level Index of 11.85.

Lots of people who aren't "altitude runners" get these factors all confused.

Jerry

[HP HUNTER]

Originally Posted by Steve Lackey

Have you tried any header tuning while on the dyno? These engines really benefit from the exhaust scavenging. That is why the original Stage 2 heads were so effective.

I tried different lengths of extensions, the best were in the pictures. Merge collectors were not tested.