I need to buy a composite polymer dist gear for a stock GM distributor to get my car moving around throughout the winter. The problem is that I have a MSD pro billet dist. that is getting fixed but its gonna take a little while. How hard is it to bore out the inside of the gear from.491 to .500. That is the difference between the 2 dist shafts. I am not buying 2 different size gear. They are $110 a piece.

 

Why do you need a polymer gear?

 

I am running a Comp cams billet cam and they instructed me that I need to use either a bronze gear or a polymer gear for things to work correctly. I have been running a bronze gear in the past but they get eaten up way to fast. I just installed a new bronze gear on my dizzy and have decided not to run it and get the polymer gear.

 

I just put mine in the mill at work and machined it with a .501 reamer. It has worked great. Any machine shop should be able to machine it.

The bronze one will work too if you set the gear height up just right and cut an oiling hole to lube the gear. I had a motor that got over 40k with a bronze gear. When I sold the motor it was hardly worn.

 

Comp, thanks for the input. Right now, im not about to modify the dzzy. I want to set it and forget so Im just gonna order anew polymer gear for a stock dizzy and then swap it over to my MSD dizzy once it gets repaired.

 

I have seen people just drill them out with a 1/2" bit but it is important for them to be on center. IMO I do not think a drill bit is the way to do it. I am sure it probably "works" but I am not into hacking stuff. Machining it on ceter is the way to go, if you want to do it right.

 

Aren't the stock roller cams billet? I ask because they don't run a bronze or polymer gear.

 

I would just chuck it up on the old lath and cut inside hole as needed.