76project

I see the article by Lars for recurving a non-HEI distributor, can something be done for my poor L48 HEI distributor?

TedH

You can buy an adjustable vacuum advance unit to adjust the amount and timing of the vacuum advance. Also, you can swap springs and the weights.

Crash80

That is where I started with my 80 L-48. It helped quite a bit on my stock motor. Of course, it lead to a head and cam change. Once you get started, the bug will get you and there is no going back. You will want more and more.....damn these cars.

TedH

I should have started there... unfortunately, I went through the engine and frustrated with apparent lacking performance, took it to a tuner who made the advance adjustments... That's when all of the performance benefits from changes up to that point really showed.

Boofers

I assume you are talking about this article?
How to set your timing for peak performance by Lars
Although the method Lars gives in this article is not recommended for setting up HEI the theory still applies to HEI.

This paper on vacuum advance units is also valueable.
Vacuum Advance Units by Lars

Basically you want the timing to advance sooner as the RPMs increase. This can be accomplished with heavier weights and/or lighter springs than stock. I found some really heavy weights in an old Buick Distributor. Using the old trial & error method I grinder modified the weights and eventually got them to work out perfectly.

SomeSayIllFixIt

Is there any place that sells heavier weights/ lighter springs?

bobs77vet

summit and jegs does so does most speed shops

SomeSayIllFixIt

Thanks, I must have missed them.

76project

Thanks for the info, looks like more research is in order.

Crash80

Heck, you can even get 'em at the dreaded Autozone or Pepboys. Just throw away the weights and use the originals.

kb2fzq

So when ya buy a spring/weight kit (and throw away the weights) is there progressively lighter springs in the kit so you know at what point you've hit the right spring and we are looking for peak advance at what RPM??

Crash80

All in at 2k if I recall correctly. There is three gauges of springs in most kits. You can also mix and match to get you there. I am using a light and medium in my distributor.

kb2fzq

I'm coming all in bet. 2500 and 2800...I need recurving?

Crash80

I wouldn't say "need" it but you might give it a shot and see if you feel any improvement in performance. Definitely read the paper of Lars that is linked in the above post by Boofers.

LiveandLetDrive

Lars recommends that you not use the weights provided in the kits, just use the stock weights. (Make sure the weight pivot-bushings are good though) The Springs are the important change. I think I'm running the lightest, I don't remember if Lars changed my spring setup...

-Chris

BKbroiler

You can't go wrong with the stock weights and the weakest springs in any kit you get. Compared to the original setup, this is a very effective way of improving performance.

Ganey

Yes.
The advance curve kits have been available at auto parts stores a long time as it's a normal part of performance tuning. The weights were never good in any I've seen & I never used the weights, just the springs.

comp