i have a sbc 350 i want to know what degree should i advance it to run the best. it has procomp hei dist. w/9000 rpm module , eddy performer airgap manifold , eddy 600 carb, excell 8.8 wires , headman elite shorty headers, 3 inch exhaust , if any of that matters, stock internals

I'm not going to claim to have any great knowledge on the subject, but I just dialed in my timing curve last Saturday on my 355. Using GM-style dist. weights and the heaviest springs in my tuning kit I am at 14 deg initial/22 mechanical/16 vac advance for a total of 52 degrees with mechanical all in by 3000. I used a Mr Gasket adjustable vac advance and had to back it out about 8 turns in order to get the right number. You didn't mention anything about your cam...mine has a pretty good lope and I pull about 13-14 inches of vacuum at idle (900 rpm). I used a Mityvac to tweak the vac advance so that it starts to come in at around 10-11 inches.

As I said, I'm no expert, but with the help of the experts on this site I learned a ton and the car is now running better than it ever has. :)

I'm not going to claim to have any great knowledge on the subject, but I just dialed in my timing curve last Saturday on my 355. Using GM-style dist. weights and the heaviest springs in my tuning kit I am at 14 deg initial/22 mechanical/16 vac advance for a total of 52 degrees with mechanical all in by 3000. I used a Mr Gasket adjustable vac advance and had to back it out about 8 turns in order to get the right number. You didn't mention anything about your cam...mine has a pretty good lope and I pull about 13-14 inches of vacuum at idle (900 rpm). I used a Mityvac to tweak the vac advance so that it starts to come in at around 10-11 inches.

As I said, I'm no expert, but with the help of the experts on this site I learned a ton and the car is now running better than it ever has. :)

How are you achieving total mechanical advance with the heaviest springs? Have you tried the lightest springs without taking out the distributor to see where you are really at?

Walter:
No disrespect intended, but I'm not sure I understand your question. I have in there the heaviest springs that came in my "HEI Tune-Up kit" (as was recommended either in the instructions with the kit or in a tech article I read), and right around 3000 rpm it stops advancing and I'm within a degree of the 36 mark on my timing tape. I considered this to be the point of full advance and is consistent with the recommendations of nearly all the posts and tech articles I have read. Is my methodology flawed? :confused:

I was looking at the springs in the kit that I have and many of the GM HEI springs are way heavier. This is probably where the confusion on "heaviest" comes in.

the cam is stock 1970 350 cid 010 block

BUSTED! Keith...you're a spy! You caught me handing out my new-found knowledge! l:)

the cam is stock 1970 350 cid 010 block

Tony:
Do you have a vacuum gauge? (a diagnostic one that you can have with you under the hood is the most convenient)
If you've got a stock cam, I've always been told that you should start at the factory-recommended initial timing (Chilton's manual?), and then slowly advance while watching your vacuum level. The theory is that you want to advance it to the point where you get the highest vacuum reading that doesn't give you any funky kicks when restarting it hot. Does that make sense? I'm sure others with more experience on the subject will be able to elaborate.

Set the total to 36* and leave it....do this with the vac advance disconnected of course. It would be nice to see that 36* in 3000 rpms, but its not an absolute necessity.

Set the total to 36* and leave it....do this with the vac advance disconnected of course. It would be nice to see that 36* in 3000 rpms, but its not an absolute necessity.

I agree. While timing at idle does matter, it only matters at idle. Unless we're talking about an engine that never does anything but idle, the amount of advance above idle is MUCH more important. 36º total is a good starting point (and probably a good ending point for most engines). If that results in more/less initial than you want, recurve the distributor. How fast you can bring the advance in varies from one combination to another but, as already suggested, 3k is a good place to start. Some combos can handle it even sooner, some may need a longer curve.

Walter:
No disrespect intended, but I'm not sure I understand your question. I have in there the heaviest springs that came in my "HEI Tune-Up kit" (as was recommended either in the instructions with the kit or in a tech article I read), and right around 3000 rpm it stops advancing and I'm within a degree of the 36 mark on my timing tape. I considered this to be the point of full advance and is consistent with the recommendations of nearly all the posts and tech articles I have read. Is my methodology flawed? :confused:

None taken my friend,

Normally, the heavy springs still advance, but way up in the rpm range, which can be a nasty surprise.

Try the lightest springs, and see where you are at on the timing tape, at 3000, 3500 and 4000. If the advance comes in too fast causing pinging, then you change out the springs to bring in the advance slower, but it will also go past your goal of 3000 rpms.

thanx ill try that

None taken my friend,

Normally, the heavy springs still advance, but way up in the rpm range, which can be a nasty surprise.

Try the lightest springs, and see where you are at on the timing tape, at 3000, 3500 and 4000. If the advance comes in too fast causing pinging, then you change out the springs to bring in the advance slower, but it will also go past your goal of 3000 rpms.

Thanks, Walter. Although this car is pretty much a weekend cruiser and spends very little time above 3500, I definitely owe it to myself to make some WOT passes down the highway and also check the timing tape at higher rpms. :thumbsup: