Small Block & Big Block Chevy Specific - timing?

i cant get my timing set right on my sbc 350. at 1000rpms its around 8 degrees (chevy specs) and it runs like shit. it runs much better advanced like crazy almost 2 inches away from the timing indicator. mabye 10-20 degrees advanced over chevy spec. does anyone know the probalem? or can tell me if its normal to run that advanced? its has a large hydraulic roller cam and aluminum heads. 10:1-11:1 compression also could 87 octane in the tank from the old 8:1 motor be causing any probalems, i hear no detenation or pinging also one more thing, it seems to be shaking quite a bit at idle, could this be because i dont have solid motor mounts, or a bad flywheel. or is it normal?

Is your carb tuned correctly?

yeah, it seems to be. i can punch it from idle and have little to no stumble.

What size cam? The 87 octane might be doing a little bit, but it shouldn't hurt it too bad with only 10.1-11.1 compression. Sometimes when you install the distributor, you can get a tooth off, and that will mess you up. I usually set the timing by ear and feel anyways, especially on a built motor. If it runs good where you have it, leave it there, I don't see it hurting anything. As for the shaking, if you have a large cam, then it's going to rattle the car a little, but I don't know how severe the shaking is in your case. Is the motor shaking, or the whole car?

with a larger camshaft you'll need more initial timing than factory.i'd try 12-16* and 36 * total by 3-3500 rpms.

What size cam? The 87 octane might be doing a little bit, but it shouldn't hurt it too bad with only 10.1-11.1 compression. Sometimes when you install the distributor, you can get a tooth off, and that will mess you up. I usually set the timing by ear and feel anyways, especially on a built motor. If it runs good where you have it, leave it there, I don't see it hurting anything. As for the shaking, if you have a large cam, then it's going to rattle the car a little, but I don't know how severe the shaking is in your case. Is the motor shaking, or the whole car?


okay, the cam is 248/254@50, 562/580 duration with 110 lsa
only the engine/trans shake. its noticeable but not like horrible. it just doesnt do that on my freinds motor in his 64 chevelle, he has a 355 with a large solid roller cam and his has no shaking at all. but he has solid motor mounts, and i have reg ones.

with a larger camshaft you'll need more initial timing than factory.i'd try 12-16* and 36 * total by 3-3500 rpms.

i dont know how to judge total timing my balancer isint marked. :bang:

okay, the cam is 248/254@50, 562/580 duration with 110 lsa
only the engine/trans shake. its noticeable but not like horrible. it just doesnt do that on my freinds motor in his 64 chevelle, he has a 355 with a large solid roller cam and his has no shaking at all. but he has solid motor mounts, and i have reg ones.

I have solid mounts in mine also. That would be a good thing to go to. That's a pretty hefty cam, so the timing will def. have to be advanced more, but like I said, I would just set it to where it runs the best, there's no way to tell how much timing is perfect because people run so many different combos.

Are you using a stock style balancer? If so they are bad about the outer ring slipping where it is made to the rubber. So your marks would mean nothing. Also if you have found that this has happened do not run the engine anymore until you get another balancer.

u need to set the timing advanced,im guessing you dont have a locked out distributor so set the timing at 38 degrees@ 2500 RPM and the thing will run,also get the 87 outta the tank,put good gas in,tune the carb right,and itll work...

thanks man i think i pretty much got it.

u need to set the timing advanced,im guessing you dont have a locked out distributor so set the timing at 38 degrees@ 2500 RPM and the thing will run,also get the 87 outta the tank,put good gas in,tune the carb right,and itll work...

I'm having the SAME problem actually. If I set my engine to 8 degrees it runs a little rough, but runs, but then when I try to start again it just backfires and makes mean noises.

Is it safe to just advance the timing to peak RPM then back it off a little for safety?
the carb definitely isn't set up right for my altitude, but once it's running I can do that.

sometimes 2500 rpm don't have full advance.mine don't until 3500 but i have the stiff springs also.i would try a new balancer and get a timing light that has the knob on the back and set like that.keep us posted.

thats a good idea to get that timing light, but it was ls1likenoothers old motor, so i will go with what he said.

That motor with our old setup went 12.1 in a 3600 lb car with 3800 degrees timing at 2500 rpmm..

And you have you make your timing come in at 2500...Hold the engine at 2500 rpm and turn the distributor until u get to 38 degrees,then tune the carb and ur car accordingly..

That motor with our old setup went 12.1 in a 3600 lb car with 3800 degrees timing at 2500 rpmm..

And you have you make your timing come in at 2500...Hold the engine at 2500 rpm and turn the distributor until u get to 38 degrees,then tune the carb and ur car accordingly..

hey, what kinda car and what trans/converter/rearend gear did it do the 12.1 in. also what was your 60 foot. im just lookin to see what it will run for me. i did around 38 degrees @ 2500, and it seems way more powerfull than it was with no inital timing. before with like 16 degrees@ it would fall on its face or make okay power then just level out.

also are those cast or hyper pistons? im just going to assume they arent forged.

I THINK those were cast...They might be Hyper-U's I bought that rotating assembly jus to get by for the time being..

It had etec 200 heads on it, a edelbrock victor intake,quick fuel 750 carb, a 2800 stall converter 3.73 gears 10 bolt completely stock leaf spring suspension in a 70 1/2 camaro weighing in at 3600 lbs cut consistent 1.70 60 fts...

I THINK those were cast...They might be Hyper-U's I bought that rotating assembly jus to get by for the time being..

It had etec 200 heads on it, a edelbrock victor intake,quick fuel 750 carb, a 2800 stall converter 3.73 gears 10 bolt completely stock leaf spring suspension in a 70 1/2 camaro weighing in at 3600 lbs cut consistent 1.70 60 fts...

cool, im a little lighter, manual, and have a 4.56 gear, i do have the victor and the quickfuel too, also i got trickflow 200cc alum heads so pretty close to the etec, i also like the cam in it very much though. pretty good price on the shotblock thanks man, i was broke, just wish you woulda tossed in them lifters. its cool though because i got them for 100 bucks, it just took like a half year to find them.