Distributor Gear for 502 HR MPI
 

I am installing a new distributor into a stock 2000 502 MPI (415 HP) I am assuming that the cam core and gear are cast iron.(correct?). The new distributor that I purchased is a GM / AC Delco part# 19420969 and it looks to be an exact same thing as the original Delco Voyager distributor which is no longer available. The new part number (which I purchased) shows to be for the GM Ramjet 502. Is the cam from the Ramjet also a cast iron gear or is it steel? In the below pics you can see the new Ramjet distributor gear on top and the original gear on the bottom. I want to be sure there is not compatibility issues here. I suppose I could put the old gear on the new distributor, but if I don't need to.... Is anyone confident on this? thanks!
https://cimg2.ibsrv.net/gimg/www.off...f87459d07c.jpg

When I pulled the cams from my 502 MPI engines, the gears were steel.

The following is from Pace Performance:

• Ram Jet 502 camshaft (p/n 12366543) notes: melonized distributor gear must be used.

• Distributor part number: 19420969 - GM - Complete distributor used with Ramjet 350 and Ramjet 50 engines. The parts breakdown shows p/n 19432310 as the replacement gear.

With that said, small cap distributors were used on GM roller camshaft engines starting in 1987 (when GM made the change to roller). GM used steel camshafts in those engines so the proper gear material was important. From all I can see, the distributor has the right gear. For piece of mind, you could swap the gears. You'd then maintain the wear characteristics/pattern of the old cam/gear relationship vs introducing something new. Shouldn't take more than fifteen minutes to swap.

Tom - thanks for the great information. I think the idea of just swapping the gear is a good (safest) one. I will measure things up and make sure the old gear ends up in the same place with the new distributor. I have never really understood the cast iron cam gear on steel core thing, then all cast iron or steel cores.

It gets complicated. All you'd need to know is here:

https://www.onallcylinders.com/2022/...r-gear-to-use/

i would take a good look at the gear on the old distributor,if it shows much ware i would replace it with a new melonized gear,remember to put some high pressure grease on the new gear,it really helps breaking in the new gear.