My recently rebuilt 350 is wandering a little bit at idle. I have the idle set at around 500rpm and the manifold vacuum is between 10 and 12 inches at this idle. The carb is an Edelbrock 1406. The cam is a speed pro with 214/224 adv duration and .443/.465 lift. I have initial timing at about 12 degrees. The car has a TH350 with stock stall (better converter coming with rebuilt tranny soon). When warmed up and in gear the engine will almost stall and then rev back up to 500 rpm, and this repeats about every 2 secs.

I'm thinking the idle might be set too low for this cam and the stock converter? I've checked almost all potential vacuum leaks except for the vacuum advance port and the power assist port. The car idled fine before I rebuilt the engine so I seriously doubt either one of those developed a leak during the rebuild.

Thanks for any help!

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ThaDex
1981 Z28
1978 LT

[This message has been edited by ThaDex (edited May 08, 2005).]

Is the vacuum advance on full manifold vacuum, or ported?

If it is on full manifold, you probably need a cannister with different specs. At 10-12" vacuum, the cannister isn't fully pulled in at idle. This results in the spark advance varying slightly, and affecting the idle speed. For a points distributor, a VC1810 ought to fix this, or a VC1843 or VC1862 for HEI. All of these will give you 15-16* of vacuum advance, and should be fully in at idle. The VC1862 will come in the fastest of the three.

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-'77 Camaro 'Original' - 357, home-ported heads and intake, Q-jet, headers, hyper flattops, ~8.5:1, 3.42 gears, 214/224-112LSA cam, 1LE rotors, D61 pads, 5642 springs
-'92 LeBaron LX sedan - all family owned, great daily driver and highway cruiser. 52mm TB, rear discs swapped.
-'70 Camaro - 350, 4-sp, nothing power, needs work, lotsa fun
-'65 Nova - 230 I6, 3 on the tree, nothing power. HEI swap.
-'70 Cadillac Sedan Deville. 10:1 472ci, TH400 - stock.