Need help! 455 wont stay idling

[theraginasian]

Please help! Trans Am with a 455 big block. It has twin 750 carbs and it wont stay running in my driveway when i crank it. i dont know why. Any ideas? Also think I overpaid. Just took it 150 miles too.

Think i just made the biggest mistake of my life! Paid $4000 for a 1980 Trans Am with a built 455. Has hot intake, bored .060 over, has a new distributor and alternator straps, dual 750 carbs, new rockers, valve job, and rings. TH350 AUTO. Interior needs stereo system and new seat cover as well as seat belts that work. Power Disc front. 3.23 posi. No rust. good glass and lights. Hood is tricky to open.

[MagicRat]

Good running, rust-free T/A's will easily sell for $4000 +, so I do not think you overpaid. It probably just needs some careful tuning.

First of all, I presume it's a true Pontiac engine, and not something else. How do you know it's a 455?

Also, what kind of carb is on it, a Holley? Setting up the correct idle mixure and speed varies depending on the carb brand.

Two 750's is WAY too much carb. That engine will run better and be easier to tune with a single 750. Consider remmoving and selling the dual carb set up, and getting a single-carb intake manifold. If you are totally in love with the look of dual 4 bbls, you can use two 390 cfm Holley carbs. They look just like the 750's, but will give better performance in a normally-aspirated configuration.

Of course the choice of manifold depends on the heads, exhaust and camshaft specifications. Do you know what they might be?

[MrPbody]

As MR says, dual carbs are massive overkill. A good running 455 needs an 850 CFM carb to rev cleanly to 6,000. No more. Also, as MR says, we need a lot more specific detail. If you're "new" to Pontiacs, get Jim Hand's book "How to Build Max-performance Pontiac V8s" published by SA Designs. This is the only CURRENT study of the ol' Injun. How to ID the engine is one of the subjects covered in there. Lots of the myth and superstition surrounding the Pontiac is also discussed. In many ways, the Pontiac is the best "street" performance engine from GM during the "muscle car" era ('64-'72). ALl the go-fast "goodies" available for the other brands are also readily available for the Pontiac. Don't let the Chevy boys tell you it's not worth building. They HATE Pontiacs, but not because they're "bad"... GTO didn't get it's reputation from LOSING!Jim

[theraginasian]

THANKS SO MUCH you two. it seemed to me that the two carbs were overkill. when i was driving it home, it smelled of gas SOOOO bad!! would like to keep the duals. can i run it on the one 750 if it gets dynotuned? should i just dissconnect a linkage?

I believe the engine is a 455, but really no way for me to know. I'll try adding pics. Receipt says carb is an edelbrock 9907 performer series. dont know if timed or vacuum choke. Also dont know what kind of heads it has but it has edelbrock chrome covers.
MrPbody, I love Pontiacs. i owned a fiero P-body!) and lost 2000 when i sold it, but i loved it for no reason . i'll see about the book too.

http://okaloosa.craigslist.org/cto/2032726075.html

[MrPbody]

Mine is an '88 GT. I DO love driving it! Not real "fast" but lots of fun in the corners! I would take that P-65 intake and those E-carbs off and put them on some used parts sales site. Get a factory iron intake if the engine's not TOO rowdy. Add a well-built Q-Jet and you'll have best possible performance. Unlike "other" brands, the Pontiac manifolds are quite good. If it's a bit rowdy (big cam, etc.), I'd suggest Torker II and an AED 850 HO (modified Holley). While dual quads LOOK cool, they're not nearly as good for performance on most street-driven hot rods as the correct size carb and a good intake.Jimp.s. Sorry for the format being "off" here. If anyone can tell me how to "turn it off", I'm listening!!