Hei distributer and roller cam question

[rogus]

You might check the bottom of the drive gear for defects to ensure it will mesh with the pump shaft, and measure the length (height) of the gear as well as the overall length from the gasket surface to the end. It's not terribly uncommon to need some adjustment- I had to shim a Mallory once on a 350 "010" block w/hydraulic FT Comp Cam.

Not that it will necessarily solve your problem but here's a short read about distributor blueprinting and cam gear differences. https://www.chevyhardcore.com/tech-...ar-meshing-can-make-or-break-your-valvetrain/

It was the dreaded .491 vs .500 gear. I never experienced this problem before but since using a .500 gear the sucker fits.

 

[rogus]

Sometimes the lower guide boss on the distributor body can bind in the block. I’ve had to hand fit a few distributor bodies to get into the block.

It was the dreaded .491 vs .500 gear. I never experienced this problem before but since using a .500 gear the sucker fits.

 

[565bbchevy]

It was the dreaded .491 vs .500. I never experienced this problem before but since using a .500 the sucker fits.

The shaft size of the distributor shouldn't matter as long as it has the matching gear.
Not really sure what you are saying fixed the issue but if you put a .500 gear on a distributor with a .491 shaft you are creating another problem.

 

[rogus]

The shaft size of the distributor shouldn't matter as long as it has the matching gear.
Not really sure what you are saying fixed the issue but if you put a .500 gear on a distributor with a .491 shaft you are creating another problem.

I got a little overly enthusiastic and wasn't quite clear. The person that owns the shop that built the engine was kind enough to come out to my home and take a look at the problem. He tried installing mine and saw that I wasn't installing it incorrectly as he couldn't mine to fit either. He had fortunately brought two other distributors with him. As you can guess the .500 distributor fit right in. I apologize if I wasn't clear earlier.

 

[565bbchevy]

I got a little overly enthusiastic and wasn't quite clear. The person that owns the shop that built the engine was kind enough to come out to my home and take a look at the problem. He tried installing mine and saw that I wasn't installing it incorrectly as he couldn't mine to fit either. He had fortunately brought two other distributors with him. As you can guess the .500 distributor fit right in. I apologize if I wasn't clear earlier.

Like I said it still shouldn't matter, I ran a stock style Ebay HEI with a .491 gear in my 355 to get it on the road and later changed to a billet MSD with .500 gear, my guess is there is an actual quality control issue with the gear that doesn't fit.

 

[bracketchev1221]

That sounds like the distributor body fit better in the block and was able to drop down.