On a pre roller SBC how much machining needs to be done to run a non retro (post 87 roller) cam in it? I heard you gotta cut back the block a bit for the timing gear, is this doable with a die grinder or does it need to be a milled surface?

 

I have never heard of that before, and I don't see why you would need to. The cams should be physically the same. You may need a harder distributor gear depending on what you use, although I'm not sure of that.

 

I agree. If you use a cam made for older blocks in an older block, it should work fine. On mine, I had to grind away some of the block to get the timing chain to clear.

 

I think 0.10" needs to be removed from the block. I'm not sure on this number so someone else step in if I'm wrong. You will have to buy "linked" roller lifters to fit in the block or the lifters will turn in their bores.

No distributor gear change is required.

 

I'm aware of all other complications and concerns


But it was mentioned that the timing chain gear has a different bolt pattern from pre to post 87, and running a post 87 cam in a pre 87 block (both being roller) the NEWER cams and gears have less clearance, or touch. Where they touch im not sure but I imagine the chain would be the first place.

 

The cams are not the same; the ones designed by the factory's undergraduate engineering intern for his junior project use that "retainer plate", so the nose of the cam is different.

I would recommend using a non-factory roller cam in an older block. No modification whatsoever of anything is required, it's a direct bolt-in.

 

at the current time htat isn't an option


gotta use the new cam in the old block