HEI for a 235 Stovebolt.

So my buddy with a low mileage '54 Chev Del Ray switched his 235 six points distributor for the HEI, bought at a performance shop up the road, (cool place).

We installed it yesterday, he was told by shop and others that he doesn't need the vac advance. On these cars, the original vac advance is hooked to the body of the original carb, and turns the whole distributer under vac.

This HEI has the vac advance very similar to the late model style, which is under vac all the time but turns the inner plate when it loses vac, so I hooked it up to the manifold vac which use to run his vaccuum wipers, (which loses vac when you accelerate, I am sure many of you guys remember those days).

It is a lot better, than what he was dealing with, but to me I still detect slight hesitation, so I am going to advance the timing a bit more today.

What say you on this idea of no vac advance? I say it is needed for his style of driving in the city, this is not a big block dragster.

The only time I don't use vacuum advance is on high performance race engines.
Hesitation coming off idle is due to accelerator pump not working right or not at all.
Timing will help a little but, it should work fine with factory settings.

Vacuum advance provides additional ignition advance at idle and at part throttle/high vacuum operation, like cruising down the highway. The ignition advance that it adds actually cuts off under acceleration. Not connecting it means you might get reduced gas mileage under high vacuum conditions but shouldn't change performance.

lazarat said:

So my buddy with a low mileage '54 Chev Del Ray switched his 235 six points distributor for the HEI, bought at a performance shop up the road, (cool place).

We installed it yesterday, he was told by shop and others that he doesn't need the vac advance. On these cars, the original vac advance is hooked to the body of the original carb, and turns the whole distributer under vac.

This HEI has the vac advance very similar to the late model style, which is under vac all the time but turns the inner plate when it loses vac, so I hooked it up to the manifold vac which use to run his vaccuum wipers, (which loses vac when you accelerate, I am sure many of you guys remember those days).

It is a lot better, than what he was dealing with, but to me I still detect slight hesitation, so I am going to advance the timing a bit more today.

What say you on this idea of no vac advance? I say it is needed for his style of driving in the city, this is not a big block dragster.

Click to expand...

Many aftermarket distributors can be set up to run either with or without vacuum advance, but there are usually internal changes that need to be made. I'd ignore the guys at the performance shop and pay attention to what the manual or manufacturer for that product says to do. If you can't find anything, find instructions for a similar aftermarket distributor as a guide.

I always thought the distributor housing physically turning for the advance on my 235 was neat.

I once bought a new snowmobile, and the salesman said to me when I made the deal "Now you have to run premium gas!". I pointed out to him that he should read the manual and that model specified only 87 octane maximum, and that a lot of people were having problems with that model of (fuel injected) snowmobile running like crap as they were using 91. When I returned to pick up the snowmobile, he thanked me for correcting him, as he had no idea he was steering customers wrong. Don't always trust the guy at the shop, sometimes he has no clue.

Thanks all, the only destructions that were in the box were for the electric hook up to coil.

I did notice a couple of extra various springs for the centrifugal internals, so further investigation is needed here

..and yes, Mr. Iron, I have discussed the accelerator pump operation with the bro, he reminds me it was a reman from National Chevy. (I have my doubts about that integrity).