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Old 06-28-2010, 03:11 PM
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1972 Pontiac firebird upgrade questions.

Ive been steadly modifing my 72 firebird. from the auto turbo 350 trans to a 4-speed muncie.
since its the weak 180hp 350 with the 2 bbl rochester and 7.6 compression ratio, ive found a few parts.
an edelbrock preformer manafold
600 holley even bore carb
and a set of heads off of a 400. the head is 87cc
and a set of long tube headers.

How much should i gain torque and hp wise with these? i was thinking 50 from the 4bbl and another 70 from the compression ratio increase.

any thoughts?
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Old 06-28-2010, 03:57 PM
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Welcome to the site,


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Old 06-28-2010, 04:39 PM
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Your estimates are real high. I would not expect the carb and manifold change to make more than 30 hp, and the compression ratio change to make more than 15 hp.

Rule of thumb on compression ratio is 1 point of compression is good for roughly a 3-4% increase in power, starting from a real low compression ratio like you have it might be 5-6%. The higher you go in compression the less a change returns. To go from 13 to 14-1 might only gain 1/2-1%.

The headers maybe another 15hp.
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Old 06-28-2010, 07:26 PM
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While you are upgrading you may want to consider a cam. I have a Summit 2802 cam for my pontiac 400

bt
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Old 06-28-2010, 08:52 PM
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Quote:
Originally Posted by beertracker
While you are upgrading you may want to consider a cam. I have a Summit 2802 cam for my pontiac 400

bt
Yea I would really love to, but there is the problem of money. If i come across a cam that i can get for a cheap price then id do it. the parts ive gotten have been given to me and what i had laying around haha.
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Old 06-28-2010, 08:57 PM
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AndersonRacing, see my reply to your other post, in this forum.

Bill
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