350 timing which one

Where does the ignition take place? Assuming you are asking about ignition timing that will be the deciding factor.

-- Regards Gordie

The Nolalu Barn Owl wrote in news: snipped-for-privacy@4ax.com:

Not sure the engine is in a 91 chev truck and I don't have any books on it. I just going to try what the other guy said. I was just wondering if anyone else has done this and where their timing was set so I don't have to guess. Kev

NOT in the oil pan. NOT in the exhaust manifold WHERE does the ignition take place? If you don't know that then you had better not play with the engine. Just my 2 cents.

-- Regards Gordie

news: snipped-for-privacy@4ax.com:

Instead of stroking your own ego with riddles, why don't you just answer his question? H

The problem is you can't really use EITHER one. Because of the 91 heads the compression is different than either engine stock. Does the truck have a computer? If so It is going to go NUTs from the knock sensor. Probably your going to have to play with it a LOT to get it to run real well.

good answer......advance the timing until highest vacuum is reached then back off a touch......test drive and retard if necessary.....if it runs good but starts hard then you may need to address the starting circuit.

Depending on your mods,SB Chevy`s can run as high as 38 degrees total.That`s what I run mine at,but I have lots of mods done.I would check the total advance @3000 rpms.Then drive it.Start @30 degrees and go from there.If it`s a total stocker,(except for the heads) it`s probably better 28-32. Also get rid of the 305 heads. Get a set of 1.94 or 2.02.

Normal total timing for a SBC is 35 degrees all in by 3,000 rpm,

10 degrees initial, 10 degrees vacuum & 15 degrees mechanical. 10 + 10 + 15 = 35 Look at the bracket that supports the vacuum canister, there is a # stamped on top of it. That # represents how many degrees of vacuum advance that can is producing, all of the factory units have WAY too much vacuum advance dialed in. If needed acquire a 10 degree AC Delco canister (can't remember the part #) Get a aftermarket curve kit for the mechanical advance then install the medium springs with the new weights and bushings. Set the initial ignition timing at 10 degrees BTDC and lock the dist. in place. Now drive it like u stole it..........