Accel/Summit HEI distributor advance curve

[leftybass209]

I recently purchased the Summit brand HEI distributor, which is the same as the Accel 59107.I'm writing this to explain the advance curve on these distributors ( I replaced my OEM because the bushings and shaft were worn and scored pretty good, and the end play was excessive, giving me 3-4* of inconsistent timing movement)

Everything i'm stating is WITHOUT vacuum advance

This distributor is limited to 11* maximum centrifugal advance with it's weights and center plate. Per the instructions it says
6* @ 900 RPM
8-10* @ 1200 RPM
10-11* @ 1500 RPM

The instructions go on to advice adding about 2-4* initial advance over factory specs, because it will add more performance and better fuel economy.

As a general rule and what most know, SBC's like around 32-36* total advance give or take.

So, that means you'd need around 21* initial timing just to get to 32* total.

This would function great with a high lift cam that needs more initial timing to idle, but not so much for a street engine.

on my 350 crate, it likes between 10 and 12* initial. I couldn't get more than 24-26* total advance at 2000+ RPM's with this distributor. Not nearly enough.

I tore down the weights and springs thinking I could use one of my 2 advance kits, or the OEM weights and center plate, but it looks like the pins are exclusive to Accel and they match what the Accel recurve kit comes with. No bushings or sleeves I have will allow any other weights or center plate to be used.

I just thought this would be good info for anyone that was in the market for a new dizzy, and was looking at this. I read the instructions thinking it was some kind of a misprint at most all factory dizzys have between 18-24* centrifugal advance and that's what I was looking for.

I'm returning this, and going to pick up an MSD Streetfire, which claims 22* centrifugal advance at 4000 RPM (which sounds spot on with late advancing OEM dizzys)

Sorry for the long-winded post, but I thought this could be valuable information for anyone in the market.