Looking for local Knowledge to tune 454 6-71 Blower Referenced Carbs-2 - Chevelle Tech
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post #1 of 1 (permalink) Old Sep 14th, 15, 8:38 PM Thread Starter
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Join Date: Aug 2013
Location: Austin, Texas
Posts: 33
Looking for local Knowledge to tune 454 6-71 Blower Referenced Carbs-2

I have a 72 Chevelle that I built an engine for and now I'm in over my head. It sounds great, but it seems to run pretty hot at Idle. Plus, it doesn't want to Idle. I have posted some videos on YouTube so you can hear it. Here is a YouTube link;


Here is a link to my project posted here on Team Chevelle with pics;


I have tried to find someone around the Austin area that could come over and maybe give me some guidance, but I have been unsuccessful. If anyone knows someone that lives down this way that could tune my setup, I will pay. The aluminum heads have huge exhaust ports and I had only 1-3/4 primary headers even though I put 3" stainless exhaust system on it, so I ordered a set of 2" primary headers yesterday from Summit. That puts my total spent with them at over $12k.
I have blower referenced Holley carbs, MSD BTM CDI box with a HE Coil, 8.5mm wires 85551M Distributor, timed at 18deg with 16deg centrifugal advance. When I pulled the plugs, they were very dark, which I was told was rich, but it seems, I'm told, to be running lean, so I am confused. Holley Black pump 1/2" hard line from the tank, 7 psi at the regulator with a 3/8" return hard line. There is only one 1/8"npt lower manifold vacuum port that is plumbed with both powervalves, but the vacuum lines for the BTM box and the boost gage and the in-line vacuum pump are all coming off of the carb vacuum port. I originally had all the lines going to the one little 1/8" port, but Holley said it recommended just the two powervalve lines to the port.

If you guys have any thoughts, I would be very excited to listen as the car is just sitting waiting for me to feel more confident that I'm not going to melt something.

P.S; The old headers were running about 500 degrees at idle. Also, the guy I had come over that I work with said He doesnt worry about the second carb. He just adjusts one carb......

Austin, Texas Hook'em

Last edited by brettallen59; Sep 14th, 15 at 8:39 PM. Reason: spelling
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