resdoggie

Stick with the HEI. Older technology that works just like the wheel.

Greengear

sparky77

You could also do what I did with my distributor on my 77 when I rebuilt the engine ,I went to Summit racing and got a rebuild kit for my H.E.I. stock distributor,75.00 and a shim kit for 12.00 .Took a afternoon and rebuilt my stock unit and now it's like new.

white one

After researching I found a few things out about not using the distributor vacuum advance. Apparently it's GM's way of lessening warranty issues on their engines. No vacuum advance, less warranty claims. I also added a Holly 650 where the directions said to use the ported vacuum connection running to the vacuum advance on the distributor. From what I can understand a ported vacuum on the carburetor base has something to do with emissions and an attempt to lessen them? Plus no vacuum is to be used for these high horse power engines (which mine is not). These performance boards say to use a vacuum advance (as everyone here has said) and to use a full manifold vacuum port to the distributor. That's my next step.

After setting the initial timing at 10 degrees BTDC and using a ported vacuum as instructed by the spec sheet on the Holly 650. Then I set the total advance timing 32 degrees at 3000 Rpm's. Idle was 850 Rpm's. After doing this I hooked the vacuum advance up. I immediately got 1550 Rpm's at idle with the idle screw backed all of the way out. I started checking hoses and connections for vacuum leaks (lots of vacuum hoses on the Vett's) I finally located a blown brake booster check valve. At least after replacing the check valve, the engine would stay running when I came to a stop, but the idle wouldn't go down below 1550 Rpm's if I used the vacuum advance. Next, I removed the distributor vacuum hose to get the RPM's down to a manageable 850 rpm's at idle. Any lower and the engine wanted to cut out when I came to a stop idling at 650 rpm's in gear at a stop.

Now, I have the use of a MSD Street Fire distributor. I tried it first, but not impressed! I may see if they have the HEI vacuum advance stop plate??? Honestly I'm not even sure anyone installed it? The distributor looks fairly clean and new? But is an unknown entity right now? If no vacuum advance stop plate is in the distributor, or they don't have it? I'm going to install the HEI out of the original engine to see if that makes any difference. I'm fairly convinced there are no vacuum leaks. The wires and plugs are all new. The timing is set according to the engine spec sheet. I may also check the plugs to see how they are doing as I did drive it for about 60 miles yesterday. Things are looking good right now. I want to get the idle down and drivability better so I can complete this task. Oh, she uses way too much fuel for my liking (around 9 to 10 mpg). Another reason I want get the vacuum advance working.

I'll let you all know what goes on and what distributor I end up with soon.

Thanks!

1999corvettels1

I'm glad I came into the C3 section, I've also been researching what distributor to run in my 1965 C10 pickup with a 396, currently it has a 1977 Caprice 305 HEI l grabbed off junked car in 1990s.

I have read MSD street fire fails often, on reviews in summit and Amazon, then the expensive MSD HEI that is almost 500 bucks has failures sometimes too.

There is a MSD advance weight and spring kit for street fire MSD (apparently MSD street fire doesn't include this "performance" kit with the street fire hei) it's about $25.00 and gives 22-24 degrees advance at max, also says can be used on stock HEI.

https://www.holley.com/products/igni...ies/parts/8428

Guess Holley bought MSD?

1999corvettels1

Also there is a MSD E curve electronic distributor that doesn't use springs and weights to advance timing, it's all done with little dials, and it's about 500 bucks, then you have to buy a MSD oil filled coil (like points distributor) bracket for coil, not sure if you need their special wires but it was over 600 for a kit!

I like the idea of the high tech tuning, but man that is expensive!

And guess what, I read about a lot of failures on these too...

Then there is a guy named Dave Ray (ignition man) who rebuilds your points distributor into a "small body HEI" and he sets the curve for you, have thought about trying him, but read it can take months after he has your money order.

Ok I'll go make a new thread, I have distributor and timing questions too.

Peterbuilt

Hi White one,
Have you seen this post? It might help you to understand why you need both mechanical and vacuum advance.

https://www.corvetteforum.com/forums...long-post.html

white one

Awesome, and all in one place! I searched all over looking for answers on different forums trying to understand all aspects of timing, vacuum advance, and carburetor adjustments. My hat is off to Barry K, and Lars. Also to you Peterbuilt for showing me this information.

Much appreciated!