Pontiac 350 in my '71 Lemans....what to do with it? - Hot Rod Forum : Hotrodders Bulletin Board
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Old 04-29-2012, 02:39 PM
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Pontiac 350 in my '71 Lemans....what to do with it?

I've got a 71 lemans I picked up for a screamin' deal and would like some advice on the engine. As of right now it has an edelbrock performer Pontiac intake with a Carter afb. Basically, the car feels gutless and I'd like to know if I should build a 383 stroker with the existing engine, or buy a 400. My dad has a 67 gto with a 400 and even with a 2-barrel on it, it throws you back in your seat and flies. I work a minimum wage job as well so my funds cannot be very high. For the biggest bang for my buck, what do you guys think?

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Old 04-29-2012, 04:55 PM
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The pontiac 350 has the same 3.75 stroke as the stroker chevy, just has a little smaller bore (3.875 instead of 4.0 )
Sounds like it just needs some tuning to get it right.
At the moment I have a 71 350 2 barrel in my 64 , and it has no lack of power.
itll smoke the back tire till its bald.
I would do some basic checking of the motor you have, it can be made to run.
You should be able to get decnt power from the 350 you have and not spend a ton of money doing it.
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Old 04-29-2012, 05:50 PM
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I would agree with LA.

Before you worry about a stroker or other changes give your 350 a chance.

Check the basics, plugs wires cap rotor, check/set timing, etc.
While you have the plugs out, run a compression check. If everything is working right that 350 should sound good and pull strong. If not, your engine may need a ring and valve rebuild which would be a good time to consider a few choice upgrades especially for things you would replace anyway like the cam.

Keep in mind that the car may have a 256 or 273 gear (common on early 70s A bodies), less kick but plenty of mph. 373 gears would give you more than boring out, for less money. Keep in mind that the Pontiac 350 doesn't scream like a sbc, it uses that long stroke to produce torque.
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Old 04-29-2012, 08:47 PM
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Hey thanks for the time, guys. Yea I don't know what kind of rear end it' got but the car tops out around only 80-85. I can spin the tire pretty easily though. It hesitates and kind of sputters almost when I go to accelerate for a second until i floor it and open up all four barrels. so I'm thinking you guys are right and it's probably some sort of carb tuning and/or timing issue
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Old 04-29-2012, 08:51 PM
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85 is the top end? at what RPM is that when doing 85?
Timing could be slow or the exhaust could be plugged.Do you have duals?
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Old 04-29-2012, 09:55 PM
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Pretty much yea...I don't have a tach so I don't know what the rpms were at but it was sounding pretty topped out. It has dual exhaust, yes. It's super loud and I think the glasspacks may need to be replaced
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Old 04-29-2012, 10:53 PM
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Quote:
Originally Posted by '71_Slug
It hesitates and kind of sputters almost when I go to accelerate for a second until i floor it and open up all four barrels. so I'm thinking you guys are right and it's probably some sort of carb tuning and/or timing issue
The ABF is not an air valve carburator, so your hesitation may be from a lack of pump shot when both butterflies ar opened all at once. Get a book on tuning AFBs or find someone that knows them. Carter AFBs are good carbs for the street, so don't let anyone tell you different.

Bill

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Old 04-29-2012, 11:15 PM
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Quote:
Originally Posted by '71_Slug
Pretty much yea...I don't have a tach so I don't know what the rpms were at but it was sounding pretty topped out. It has dual exhaust, yes. It's super loud and I think the glasspacks may need to be replaced
Is the transmission shifting into drive?
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Old 04-29-2012, 11:57 PM
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Yea I have heard very good things about the afb. My dad was saying the same thing about the pump thing because when we rebuilt it he seemed to think it wasn't plunging enough right off the bat for the first initial squirt. And yes, cobalt it shifts nicely and everything, no problems there.
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