89silverado283

i got a 1989 silverado with a 4 barrel carb off a '72 350 pickup truck rebuilt and cleaned the carb, i put 120 psi through the jets, and adjusted the floats from the 350 to my 1967 283, I SET THE CARB FOR A 327.. let me explane the 283, 283: 283 lower end, 327 camel hump heads "and yes im positive there camel hump" its got a small cam im not sure how big but its got a bigger cam then stock. so now i got a 1989 silverado with a 1967 283 and a 1972 250 carb... 1st problem i had the timing at 12 degrees and i have heard i should be at 4 degrees any help on that would be cool... and my final problem is if i put my peddle to the floor it starts to spit once and awhile it dont some times it just screams my floats at 9/32, am i under carb or do i need a better carb my carb is a 4 barrol rochester Quadrajet. and when i go up a hill i got NO power. i got the engine with the truck the stock 350 tbi had gone bad when i got the silverado and the kid gave me that 283 and said it had like 300miles on it... i have put withing like 1500miles on it in just a few months.. could my cam be flat?? thanks for the help. and sorry for the novel.

therewolf

Sounds like you're a little off the published page, so why not try the old "time it by ear" approach?

1)Mark your current timing with chalk or a dab of paint in case you want to return to it.

2)Loosen the distributor. Start the engine.

3)Use a heavy rag or glove, grasp the top of the distributor gently and slowly ease it advanced until you hear it start to ping & shake a little, then back it off until it smooths out.

4) Tighten the distributor. If it doesn't perform to expectations, return to the marks at step#1.

89silverado283

yeah thats what you said on that other page.... im gonna try timing it like you said but i did state that im running at 12 degrees (btdc) i heard that i should be at 4 degrees (btdc) now if im at 12 am i advanced or behind???

suzuki-guy

Clockwise advances it counter retards it you want to advance it till it pings then move it back till it stops and that should be perfect you got a timing gun right? If im not mistaken there should be a wire you have to unplug to actually move your timing if you move it with it plugged in it will move itself back to factory setting. I know they have this on my 95 and i beleive this was on 1988 and later. Its a tan wire underneith the glove box when you unplug it your truck should idle down then you move your timing shut your truck off plug the wore in and unplug your battery to reset the computer

therewolf

Short answer: You're advanced.( PAST 4 BTDC to 12 BTDC FROM "0" {which is TDC})

My guess is you want to be at 8 or 10 BTDC, but I've never seen the system, and I'm just working from what you've told us.

You should definitely mark it when you get it right. It'll save a lot of time and confusion later.

89silverado283

did i mention that it doesnt back fire out the carb BUT it does POOF.... and when im at about 2500rpm and let off the gas it pops and sputters tell it drops in rpm or i hit the gas... i had an old timer tell me the other day i might have a flat cam... i did a cap, roter, and plugs swap the other day and my #8 was not sparking and had like a had oil build up on it, and #7 was way wet... im going to go and try diffrent timing right now...im at 10degrees i cheacked it lastnight...

89silverado283

ok i tried timing i had it at 5 degrees shut my truck off started it and it was at 12 degrees... i made sure my timing light seting didnt change and it was still at 5 on my light.... the only TAN wire i see is in a preety big wire harness... where exactly is that wire you mentioned???

suzuki-guy

dude im telling you its your timing if it still has the original wiring harness on it you will need to unplug that wire under your glove box or it doesent matter where u move your timing it will set itself back i went through the same thing. The wire is tan and under your glove box do exactly what i said yesterday the wire is not in your engine compartment its kind of weird but thats chevy for ya

89silverado283

k i understand all this im just wondering whitch one of the 6 TAN wires i have UNDER my glove box...
i have one thats in a wire harness that goes to the sub frame and i cant trace it after that the others are on BOTH wire harnesses on the brain box... whitch tan wire???

suzuki-guy

on mine it is a single tan wire not in a wiring harness or anything i can take a pic if you want but mines a 95 urs is an 88 right? The wire unplugs right there at your glove box you dont need to trace it anywhere! If there is a tan wire that you can unplug at your glove box whiule its running unplug it if the truck bogs down you got the right wire