HEI distributor cap upgrade(?) worthwhile on stock 350 5.7L?

[Evets]

Greetings,
First Chevy truck, first post, and first time saying "Thank you" for all the information I've already received via lurking.

As part of resurrecting a new-to-me truck that has been sitting/dead for the last 9 months, I'm going to attempt my first tune up in 25 years. My question is this: Is there much (any?) improvement in operation to be had by replacing the stock AC-Delco dist. cap with a Davis Unified Ignition Street/Strip Coil Kit ($79), or something similar, as part of the overall tune up? The 350 5.7L is stock and I have no plans to upgrade cam/manifold/exhaust/etc. at the moment.

https://www.summitracing.com/int/par...illocation=int

Thanks in advance for any advice you can share.

-Steve

[Chevy1966]

Welcome - you will find a wealth of information on this forum.

I for one am a big fan of the Delco designed HEI. You can learn a lot more about it here:
http://www.ebay.com/gds/HEI-Ignition...2053885/g.html
No experience on my side with the Davis unit, but the concept of the HEI - essentially an electronic ignition without the conventional points - is a winner. Keep us posted!

[Ironhorse]

First off, Welcome to the best Chevy/GMC truck board on the net!!


Also have no knowledge of the Davis unit but when I swapped my SM465 4 spd truck trans in my '71 4x4 to a TH350 auto I went with a Petronix HEI conversion unit. My truck being a 4x4 the engine sets farther back to the firewall, no room for a standard GM HEI unit. The Petronix conversion works using the original points distributor unit and the standard cap with the points adjustment window. The entire unit fits inside the cap, very easy install. Looks completely stock, been using it now for almost 4 years. No problems, just my .02 worth of experience.

[Dead Parrot]

If your existing HEI works, keep it. When the HEI first came out, GM recommended a plug gap of .060, later narrowed a bit to .045. No real advantage to higher voltage on a stock engine since the stock unit is operating well within its comfort zone.

I would check the little button in the middle of the cap. If that is wore out, performance can suffer. Also check the mechanical advance for sticking and the vacuum advance for leaks.

[Evets]

Thank you, everyone, for the welcomes and for the advice. It looks as if I would be better off spending money elsewhere, and there are plenty of elsewheres that need attention, like the flat spot in acceleration that hits at 30 mph, but that's for another thread... Thanks again.

Steve

[El Dorado Jim]

Originally Posted by Ironhorse

First off, Welcome to the best Chevy/GMC truck board on the net!!


Also have no knowledge of the Davis unit but when I swapped my SM465 4 spd truck trans in my '71 4x4 to a TH350 auto I went with a Petronix HEI conversion unit. My truck being a 4x4 the engine sets farther back to the firewall, no room for a standard GM HEI unit. The Petronix conversion works using the original points distributor unit and the standard cap with the points adjustment window. The entire unit fits inside the cap, very easy install. Looks completely stock, been using it now for almost 4 years. No problems, just my .02 worth of experience.

thats weird, I have a 72 K20 and I installed a gm HEI in mine with no problem,but I put it in without the cap on maybe that makes the difference...

[Malo83]

I'm running the HyperTech Power Coil on my 83 305, opened up the plug gap from.045 to .050, smoothed out the idle and gave the engine a little more pep
https://www.summitracing.com/parts/hyp-4050