Engine was running perfect, but had a 4-6* bounce at idle so I replaced points distributor with a new Summit HEI. Also new Moroso wires and AC plugs. Ran the + side straight to IGNITION on fuse box with a 10g wire. Car ran fine, although seemed to be down on power compared to the points, but I thought I just needed to get my curve worked out. But now, when I stomp on it, at about 4000 rpm it sputters, cuts out, and sometimes even dies and then starts back up. Sometimes it doesn't do it, but most of the time it does. Timing is set at 12* initial. I have installed a Crane adj vacuum advance and used their recommended blue/silver spring combo. This has made no difference. Car idles and drives fine, until around 4k rpm.

Any ideas? Did I get a junk Summit HEI. Half temped to yank it out and put the points back in just to see.

Thanks guys.

First thing I'd do would be a power balance test, to see which cylinder is bad.

Well, I put the points destributor back in and it runs fine. Wonder if the module in the HEI is bad?

Calling Summit tomorrow, I think this HEI is a POS.

just guessing but I would tend to think the coil is junk or not assembled in the cap properly :D

*** UPDATE ***

Received my newly exchanged Summit HEI, put it in, fired it up, set the timing. Car runs fine up to 5500 rpm for 2 weeks. All of a sudden, the same problem comes back - jump on it and it cuts out, stumbles, dies, and starts back up. Sometimes it doesn't do it, but most of the time it does.

What gives? ANY ideas? It seems with the old points distrib I had zero problems (except the 4-6* bounce), and now 2 brand new HEI's and I get this very strange problem...

I'm not sure if you read the post I made.After going through all that it ended up being plugs.They were new delcos and I only put maybe 15kms (not 15,000)on em. I was thinking they mighta been chucked around at the store and maybe some of the ceramic was cracked or somthing.I got them at crappy nd they dont know their a$$ from a hole.

Browntrout,

I’m not familiar with the distributor you have so I’m shooting in the dark. Did you gap your plugs correctly? HEI requires a larger gap. Try setting you timing at full advance, not initial. Can you get larger weights for that distributor if needed?

Good luck,
Bubba

sorry

I have my plugs gapped at .045, they are fairly new (~100 miles) AC R44XLS. I have been thinking of changing just in case, but then I think why did it run fine with the points distrib if the plugs are bad? I still may try though. Right now I'm at 12* initial and I think 32* total by 2800 rpm - need to double check again. Maybe I need to work on my timing curve? Would not enough advance cause an engine to cut out and die? I have the BAT going to IGN on my fuse box, so I should be getting a full 12 volts, but I guess I should check that also.

Bubba - weights are standard GM HEI, so if they make different/bigger ones I'm sure I could use them. The weights just control advance speed, right? Maybe they're too light and not advancing fast enough or far enough at WOT?

I'd try setting the total advance a little higher. Maybe around 36 to 38 and see how that works. That should help out at the higher rpm's.

Bubba

Bumped my timing 6*. Problem seems to have gone away. I think the Summit HEI distributor either 1. sticks sometimes and doesn't advance properly and/or 2. doesn't have enough mechanical advance. I need to get a timing tape to verify.