How difficult is it to recurve a stock chevy dist.w/ vac advance to reach the proper total timing when using a mid street cam on a big block?My initial is at 16 degrees now (idles best there)and my total is at 44.Seams to be OK but I know the total should be around 36.I want to keep using my stock dist w/ points.:thumbsup:

Total advance is measured without vacuum advance. If you want 16º initial and 36º total you need 20º mechanical in the distributor. Ideally, your vacuum advance will add another 12º-16º on top of that. Crane and others make adjustable vacuum canisters to give you more flexibility.

Exactly what Jerry stated is the proper thing to do.

Scott

Yep, correct, need a distributor machine to do much better...

FUNNY YOU MENTIONED A "DIST MACHINE".

I just bught a " supposedly properly working SUN 404 dist machine " from back in the day to have the ability to setup the mech adv curve in the distributors for peoples cars that i work on.

I am very busy with work/holidays but i will hopefully get the time to plug it in and fire it up to see what what the helck its all about.

I actually was lucky to find a quick setup inst manual on ebay for that exact model Sun 404 machine for $10 so i donyt think it will be too hard to figure out.

Anyway,if the machine works ok like it was supposed to then after i learn/master it i will then likely offer to dial in the mech adv on stock gm type v8 distributors for people for reasonable price which would include my fellow t/cr's too.

But i am not there yet.

Scott

How much different that this one?

if your running 20* and 18 mechanical for 38 total in at 3k, is it good idea to hook the vac advance up? i have mine unplugged because i saw too much timing with it, but if it helps performance, then ill plug it back in.

thanks

aaron

if your running 20* and 18 mechanical for 38 total in at 3k, is it good idea to hook the vac advance up? i have mine unplugged because i saw too much timing with it, but if it helps performance, then ill plug it back in.

thanks

aaron

Plug it back in. You can go 48-52* of timing with your advance hooked up. Your engine is NOT under load at cruise, so it is safe. It will help tremendously with efficiency and keeping your plugs clean. Get an adjustable one to dial it in. :thumbsup:

i currently have a billet msd dizzy.. ready to run version with 6al box..
thanks

aaron

i currently have a billet msd dizzy.. ready to run version with 6al box..
thanks

aaron

You are very welcome. I just set up my SBC to have 50* timing (total + vacuum). You will like how well it will run. Merry Christmas.