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Old 04-15-2017, 10:55 PM   #61
HP HUNTER
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Talking Re: 1971 Buick 455 GS F/SA G/SA Build

I finally got the exhaust side of my heads done. Although I'am not sure I have this right, so I have questions. On my BBC builds with conventional camshafts I've always wanted lazy low lift flow then have it come on after .300 lift and take off, this has always worked well for me. On my Buick I gained around 12 CFM @ .200 and 12 CFM @ .300 and about 10 CFM @ .400 and finally 9 CFM @ .466 peak lift, will this help me or hurt me?
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Old 04-17-2017, 09:59 AM   #62
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Default Re: 1971 Buick 455 GS F/SA G/SA Build

I almost didn't answer this because there's not enough info to make a valid response ( again, where are the .100 flow figure improvements on intake & exhaust). Also, i don't know what was done to improve the intake or exhaust flow. You are definitely going to have a (seemingly) wilder cam with low lift flow increase. You will have more reversion, true, but, in my opinion, you are going to see a substantial performance increase. Ron.
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Old 04-17-2017, 09:07 PM   #63
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Default Re: 1971 Buick 455 GS F/SA G/SA Build

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Originally Posted by R. Thorne View Post
I almost didn't answer this because there's not enough info to make a valid response ( again, where are the .100 flow figure improvements on intake & exhaust). Also, i don't know what was done to improve the intake or exhaust flow. You are definitely going to have a (seemingly) wilder cam with low lift flow increase. You will have more reversion, true, but, in my opinion, you are going to see a substantial performance increase. Ron.
Ron, I will send you the flow numbers in .050 increments, I'm actually scared to to see the increase @ .100 lift on the exhaust. Intake to exhaust flow is roughly 67% @ peak lift.
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Old 04-20-2017, 06:38 PM   #64
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Default Re: 1971 Buick 455 GS F/SA G/SA Build

Sorry for delay, Mark. As Mike Taylor, Adger Smith, and others have said total and/or average flow is more important than peak lift flow increase at the expense of lower lift flow. I did not see anything exorbitant in your low lift exhaust numbers. Frankly, there is probably more potential low lift available. There are, of course, ways around the reversion issue if that is what concerns you, but I don't think you will need it. In short, yes, IMO, it will help you. Ron.
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Old 04-30-2017, 08:54 PM   #65
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Default Re: 1971 Buick 455 GS F/SA G/SA Build

Heads are finally installed on the engine. I would not look forward to doing another set like this Now I've got to fit the intake which I could see taking a day to get a good fit, then its dyno time.
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Old 05-12-2017, 10:13 PM   #66
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Default Re: 1971 Buick 455 GS F/SA G/SA Build

My preliminary dyno results are in, peak HP so far is 513 HP/550TQ. I will be making some changes looking for more, I will post up the results when I get done. More work and more HP 522 now.

Last edited by HP HUNTER; 05-16-2017 at 09:36 AM.
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Old 05-19-2017, 11:41 PM   #67
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Default Re: 1971 Buick 455 GS F/SA G/SA Build

I finally finished the engine part of my F/SA build. I want to say thanks to the following people for their help.

Harold Bettes
Jim Lewis
John Lewis
Chris Skaling

Dyno test from before the engine had been gone through is on the first page of this thread, dyno test of the finished product below.
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Old 08-10-2017, 09:15 AM   #68
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Default Re: 1971 Buick 455 GS F/SA G/SA Build

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.
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Old 08-19-2017, 12:37 PM   #69
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Default Re: 1971 Buick 455 GS F/SA G/SA Build

Congrats on your hard work paying off. Nice power. Small valve low compression engine. I look forward to hearing about testing now.
Chris
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Old 08-19-2017, 09:56 PM   #70
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Default Re: 1971 Buick 455 GS F/SA G/SA Build

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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.
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