The Ford Barn

Bored&Stroked · 03-06-2024, 11:17 AM

The original Potvin 425 Eliminator cams were usually done on billet steel 32 cores - with the bearing journals done to .010 undersize. The undersize journals were usually done because in 32 there were no cam bearings in the block - so the cam just ran on the cast iron. Due to this, an older cam might be worn a bit in the journals - so .010 made sense.

Given how small the base circle needed to be to achieve .425 lift, Potvin felt the 32 cores were better than cast cores. Also, some believed that the steel cam would last better than a cast one - as the Potvin 425 profile has a sort of "point" at the top. This is the only Potvin cam that has that lobe profile that I've seen.

I had a 425 that was ground by Bill Jenks at Moon - it was a cast core cam that had the tops of the lobes welded up. What I don't know is . . . was that done to achieve the lift needed, or was it done to make the top of the lobe last longer. I never had a chance to ask Bill the reason.

I recently had "Pete" regrind a 32 core with the Potvin 425 profile. It still has the original "press on" type of gear on the front - which actually makes setting the cam timing easy.

03-06-2024, 11:17 AM	#3
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,906	Re: Potvin cams The original Potvin 425 Eliminator cams were usually done on billet steel 32 cores - with the bearing journals done to .010 undersize. The undersize journals were usually done because in 32 there were no cam bearings in the block - so the cam just ran on the cast iron. Due to this, an older cam might be worn a bit in the journals - so .010 made sense. Given how small the base circle needed to be to achieve .425 lift, Potvin felt the 32 cores were better than cast cores. Also, some believed that the steel cam would last better than a cast one - as the Potvin 425 profile has a sort of "point" at the top. This is the only Potvin cam that has that lobe profile that I've seen. I had a 425 that was ground by Bill Jenks at Moon - it was a cast core cam that had the tops of the lobes welded up. What I don't know is . . . was that done to achieve the lift needed, or was it done to make the top of the lobe last longer. I never had a chance to ask Bill the reason. I recently had "Pete" regrind a 32 core with the Potvin 425 profile. It still has the original "press on" type of gear on the front - which actually makes setting the cam timing easy.