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Old 07-03-2012, 01:50 AM
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72 Lemans 350 getting more power

Right now its the stock 350, 7H1 Heads, looking to do a head swap, and along with that i already changed the cam and lifters, timing set, i have headers, holley 4 barrell and so on. Please let me know of any and everything i can do to this motor( i know it isnt a racing engine or anything) but what can i do to it as far as manifold, carburetor, distributor kits, heads, boring or stroking it, transmission work (TH350) and anything else please let me know!

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Old 07-03-2012, 07:21 AM
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Boy that would take a book to answer. Maybe give some parameters on where you want to go. Such as money you want to spend, street car, supercharger turbo nitrous race gas, pump gas, e85. That would help everyone help you. I think budget is the most important for me anyway. Then if you make gobs of power will the rest of the drivetrain hold up. Too much power on the street will you get traction. ugh lots of questions to this question.
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Old 07-03-2012, 11:59 AM
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So what cam did you install? What intake manifold? How "big" are the headers? What Holley?

350 is a decent engine, though not a GREAT one. One cannot make the same level of power as 400 without jumping through a BUNCH of "hoops".

The better 350 heads are the '69 17s and 47s. Even though Pontiac used the 48 ("large valve") head on SOME 350s, it's better to use the small-valve heads. The bore size is so small it impairs intake flow significantly.

Jim
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Old 07-17-2012, 02:49 AM
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I have the edelbrock performer, a 600 Holley 4 barrel, hedman headers not too big I believe 2 1/2 inch pipes each to a 3 inch collector, its a comp calm I'll dig up the spec card and get that on here as soon as I can, and I'm just going to drive it on the street nothing crazy but enough to get a lot put of it and its gonna be over time so not a huge budget but a mildly modified budget. Which of those heads would you suggest?
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Old 07-17-2012, 07:13 AM
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Can't tell you a whole lot until I know what cam you're tunning. As for the 17s vs. the 47s, well, flip a coin... A d-port is a d-port is a d-port... Very little difference between ALL d-port heads except valve and chamber size.

Keep compression at or under 9.5:1 for 93 octane gas.

Jim
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Old 07-17-2012, 08:35 AM
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i would look at the differential gear first before anything.
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Old 07-17-2012, 09:46 AM
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[QUOTE=woj's72lemans;1574508] hedman headers not too big I believe 2 1/2 inch pipes each to a 3 inch QUOTE]

Not too big? I'm guessing that's a typo, and you meaant 1.5" pipes into 3" collector. Even the larggest big blocks don't use 2.5" primaries.
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Old 07-17-2012, 11:38 AM
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Yes that is a typo 1 1/2 to 2 inches and okay thank you .. ill find the cam specs and let you know
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Old 07-17-2012, 01:42 PM
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I agree with a gear ratio change before any more engine work.
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Old 07-17-2012, 05:45 PM
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I would dig up a low profile single pane intake manifold like the
pontiac edelbrock torker II and adapt a Edelbrock/Magnuson E Force supercharger or a Weiand 142 supercharger to it.


A simple blower friendly cam like a Crane H-288-2 #283951
Use a 750-850 cfm carb. With a few blower mods and rejetting.

Home port the stock heads. Possible larger valves.

The stock pontiac bottom end is plenty strong for modest boost
5-6psi and already has a desirable low compression ratio.
It will go like hell.
Get some 4.10's and a 10" 3000+ stall.
A recurved GM HEI pontiac distributor gets it done. Use a bloer friendly timing curve ( Adding a boost retard box is a nice option.
Upgrade the fuel system on the car.
Use 92+ octane gas.
The blower to manifold adapter plate can be custom fabed from aluminum plate
and the blower drive compenents can be sourced from Edelbrock.magnusun and or Weand/Holley.

The result will be well worth the effort.

this professional products hurricane intake has potential to be adapted to the blower with a mounting plate

Last edited by F-BIRD'88; 07-17-2012 at 05:57 PM.
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Old 07-17-2012, 06:41 PM
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Quote:
Originally Posted by FmrStrtracer View Post
I agree with a gear ratio change before any more engine work.
i agree also. But before a change, let's determine what it is first.
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Old 07-18-2012, 01:16 PM
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The owner before me put in a 71 non posi rear end how exactly would I find out what it is?
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Old 07-18-2012, 01:39 PM
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Quote:
Originally Posted by woj's72lemans View Post
The owner before me put in a 71 non posi rear end how exactly would I find out what it is?
Jack one wheel, off the ground, put the tranny in nuetral, spin the free wheel two full revolutions, count the number of revolutions of the drive line. Be sure to have a jack stand under the car for safety.
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Old 07-18-2012, 08:54 PM
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Quote:
Originally Posted by woj's72lemans View Post
The owner before me put in a 71 non posi rear end how exactly would I find out what it is?
A page w/info to help is here.
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