Difference in HEI Distributor Caps?

[BigRandy]

I have a HEI distributor that I bought used for my '74 454. I don't know what engine it was in but it seems to be working fine, although there is an intermittent but noticeable stutter above idle which could anything from a worn bushing to bad wires. The cap and wires are fairly worn and I want to replace them but since I don't know where the distributor came from I don't know which cap I need, or if it matters.

The reason I ask because I see caps with different part numbers and some that claim to be good with any SBC\BBC distributors, sort of a one size fits all, but seeing some with different part numbers tells me they aren't the same.

My gas hog 454 is almost dialed in and running great except for the intermittent miss which sounds spark related. I've got new R45T plugs gaped at .45 and I believe I could start it with a hand crank if I had the arms for it. Just trying to get rid of the stutter now.

It's possible the stutter could be from a worn distributor. My gut tells me it probably is but I haven't checked it yet. I had a worn distributor once many years ago but forgot exactly how I found it. Should I feel for side play in the shaft or look for something else?

Many thanks for any advice!





Thanks

[Ironangel]

I put one of these in a buddy's built small block last Fall and that motor still purrs at idle and rips the street up when he steps on it. https://www.ebay.com/itm/SBC-Chevy-P...ke%3AChevrolet I dont usually condone Chinese made parts but this is a good unit for the money.

[Hollow65]

Pull the cap and manually move the advance and see if snaps back.

[BigRandy]

Originally Posted by Hollow65

Pull the cap and manually move the advance and see if snaps back.

You may have something there. Sometimes it turns over a little hard as if the timing is too far advanced. A couple of weeks ago I backed it down from 14 to 12 BTDC and most of the time it spins like a top - but not always. I'm wondering if the vac advance isn't hanging up.

I have no history on the dist. The guy said he had one and I wanted to ditch the points so I got it cheap. I checked and everything moved freely and the advance returned with no problem. The shaft end play was out of spec by about 20 thou so I bought a shim kit. I don't remember the recommended spec but a but it was back to spec after installing the kit.

Maybe the problem is more than the wires and cap. Since those EB dist kits have good reviews I may just get one and hopefully take care of it that way. $50 is cheap if it works.

[BigRandy]

I bought a complete distributor from EB plus Moroso wires. Got them in today and if looks mean anything they should be solid enough to last for the rest of the engine's life. I have 107,000 miles on it and the old plugs look good. No sign of oil but I do have a rear main leak and have to add a quart every 600-800 miles. Thanks for the link.

For the price I opted to go with all new ignition instead of rebuilding what I had. I don't know how many miles are on it but it had close 40 thou of end play or more before I shimmed it the last time.

I don't have a timing tape so should I time it by ear or go for base and see what happens? According to a slip of paper included with the new dist it has a max of 20 degrees advance, so if I set it to 12 it will be all in at 32. That's 32 at 4500 which it never sees. Most of the time I don't go above 3500 RPM

[BigRandy]

Thanks for the help and suggestions. I pulled the old dist today and it's junk. Advance froze solid. Got the new dist kit from skipwhite on EBay, completed the swap and it fired right up. The difference is amazing. Not sure how well the new dist will hold up but if I only get 25K it's still worth the $52.