Did a quick search and couldn't find a specific answer to my question. I've got an 87 roller motor, with unknown cam. Planning to change to a mild melling cam and change the lifters. The distributor is a Mallory set up, it came from a hydraulic motor (84) I've heard using a rollers use a different dist. gear. Is this true? If so can I swap the gear out for the right one?

 

no you should have to replace nothing on the distrjust make sure you time it right

 

Call Melling and find out what they recommend for the cam you are installing. Most roller cams require the use of a bronze gear.

Hydraulic motor (the 84) as in a hydraulic roller retrofit or hydraulic flat tappet?

 

I know when i used to work on the Ford 5.0 motor, the hydraulic roller cam had a steel gear and the distributor had one to match. I know for a fact that on those motors if you were to use a flat tappet hydraulic roller cam , then you had to change the distributor gear to an iron one. If not , if you were to use the "roller" distributor , then it would tear up the iron gear on the flat tappet cam. IDK for sure on GM motors, but i would investigate further if i was you.

 

Hawkz28 is probably right. You will have to knock the small pin out of the dist. shaft to get the old gear off or, buy the dist. gear you need and have a shop do it for you . I think i was quoted like $25 to have it pressed on.