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Joined: Mar 2003
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my car is an original 350 c.i. 2 barrel car. came with 265 hp and has a TH350 auto. i has the original heads i believe they are the #17's. i recently did an aluminum Edlebrock intake manifold swap and a Edlebrock Carb. i heard that by doing this i only hurt my performance and that my car will run real ****ty? what if a get a quadrajet to match the specs will this help a little?


"Live and let live" matching #s 68 firebird
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So Banshee, when you only swap the carb and intake are you only getting a tad more performance or is he getting less HP or just not optimizing his HP. As far as HP is concerned, where would he be now that he made the carb and intake swap. Same,more or less? smile


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Thanks Banshee. So basically what you are saying is that if he does not do any head or cam work or upgrade those items to 4bbl parts,he might as well reinstall the 2bbl intake and carb as he will have better performance and mileage?
David. laugh


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Man you almost beat my reply!!! laugh


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If i don't get this car back on the road soon i'm gonna go postal!
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Does this go true for all motors or is this pertanant to just pontiac's? ok so all i need are some H.O heads and a H.O cam and i would be ok!


"Live and let live" matching #s 68 firebird
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oh sorry i was asking a question


"Live and let live" matching #s 68 firebird
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Banshee, just trying to learn some things here. What about the pistons? How do they factor into the mix with all of the afformentioned changes?
David. smile


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If i don't get this car back on the road soon i'm gonna go postal!
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What would happen if he replaced the 2 bbl with a small 4 bbl (like 500 cfm). Would it still not run right? I guess I don't know how much air a stock 2bbl will move.


Bruce

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I don't see the loss in HP by just changing to a 4bb. Yes it would be a miss match and not be the best combo in the world but as long as you are using a Q-jet and not a Edelbrock carb you would still feel a performace diffrence. I have change 2bb to 4bbs and thought it was a great change.

One of the magazines did a engine dyno where they did incremental changes with the intake, then the cam and then the exhaust maybe not in that order but it showed small increases until the last restriction for the motor was replaced and then you saw the HP really jump.

Getting a Q-jet to work well with a restricted 350 should just be a matter of increasing the tension on the seconday spring to avoid bogging all the time.

just my .02

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Banshee, what's your opinion on my situation...I have a numbers matching '69 400 with 62 heads. I rebuilt the engine to have 9.5:1 CR (by putting in dished pistons) and had the heads fully ported. I'm running the stock intake and stock carb that I had Cliff Ruggles dial in before I had the heads ported; he didn't factor in the porting when he set up the carb. I'm running the 068 cam.

I'm still not happy with the low end performance of my setup...there isn't enough torque to do a burn out. When it gets up to higher rpm's there is tons of power and will chirp the tires when it goes into second and sometimes third.

Do you think the problem is with flow?


Dan Dykstra 1969 Firebird 400
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rohrt, may be wrong, but I think what Tom was getting at was with the edlebrock carb and the engine set up for a 2bbl, the carb would dump to much fuel for the engine. Maybe not as much of a HP loss but still very inefficent, not any gain either.

From everything I have gathered, the stock pontiac intake with a well tuned q-jet outperforms any aftermarket part up to 5500, and the performer intake will either slightly drop or not change at all the performance.

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I personally like the "Biggest Surprise" at the bottom of this link:

http://www.wallaceracing.com/ultimatehead.htm

At least 350 heads do something well.

G.J.
68 350 Coupe


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"The Crying Game" also had a big surprise, though.

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Banshee, I'm running what appears to be a stock converter with no stall and a 3.55 posi. I don't have flow measurements on the heads. The guy that did them said, "no one told me to flow them so I didn't; I'd be happy to if you brought them to me."...yeah right, I'll just pull them right off the car. That's what I get for letting my idiot mechanic deal with him instead of me dealing with him myself.

He did a full port job include port matching and bowl work. He also replaced every valve guide (that's originally why I pulled the heads off and then decided to get the work done while they were off) and did a five angle valve job. They should flow pretty **** good since I spent $780 on all that head work.


Dan Dykstra 1969 Firebird 400
Starlight Black Convertible w/ AC
http://FirstGenFirebird.org/show/closeup.mv?CarID=489

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