I have a timing issue with my '67 GTO 400. It runs best with the base timing at 39* BTDC at idle. No pinging but overheats quickly. Not sure why it won't run if I set the base timing down in the 8* range. I'd like to have my distributor tested but can't find anyone locally that has a distributor testing machine. I went to 4 different restoration shops & talked to 4 different mechanics and they all told to to can the stock distributor and put in an MSD electronic distributor. I'd rather not.
I've found several distributor restoration shops searching online. Has anyone had any experience with a distributor restoration shop? Any recommendations?
Gotta be something wrong. With the vac advance unhooked & hose plugged, (You DID have your vac adv unhooked, right ?) it should idle OK at somewhere near 10° or a little more. Back in the old days, I set my 455 bracket engines at 13° initial. Some like as much as 18° or even 20°.
I'm guessing that if your timing light is accurate, the outer section of your balancer may have slipped.
Think about this. Most engines run best at 4000 or more rpm, with aprox 32-36°. But, if you have 39° at idle, that would put your total advance , at 4000 rpm +, about 50°, if your centrifugal only adds 10-11°. And most dist are set up to have more than 10°. I've read of some that set theirs up with 12° initial & 24° centrifugal, so they'll have 36° total mechanical. Then, for street cruising, they also run a vac advance to add a little more at low rpm cruise conditions.
You mentioned overheating quickly. It is commonly posted that low advance can cause overheating. So, maybe even tho your timing light is showing 39°, your ACTUAL timing is MUCH lower.
What does your timing advance to, as you get to 3000 rpm ? 4000 ?
Opinions about how a timing curve should be set up varies all over the map.
Pontiac Street Performance - Initial Timing Question
"...Has anyone had any experience with a distributor restoration shop?..."
I recently bought a Cardone rebuilt factory HEI. Probably not high quality. But it was cheap. Paid $80 on Ebay. Guessing that most commercial dist shops would charge 2 or 3 times as much, to rebuild one. I replaced the module, which was a GM #466
, with a Pertronix D72000 rev limiter module. Also added a screw to make a positive centrifugal advance stop. Haven't installed it in the car yet.
Cardone also sells rebuilt point dist. Can get 25% online discount code for Advance. Have used it several times.