Question about converting to a roller cam

I'm looking at possibly converting my Mark IV motor to a roller cam. I know I'll need to find roller lifters, pushrods, and a distributor gear. I already have a stock gen 6 camshaft that appears to be in good condition and I'd like to use that vs spending $500+ for a bbc roller cam. Looking at pictures, the timing chain end of the gen 6 cam has an extruded part while most other cams have a "flat part" pics below:
gen 6 camshaft


Aftermarket camshaft


In order to "retain the cam in place, is there a specific cam button to use with the stock style camshafts in a mark 4 block? and is there a specific timing chain set I would need to use as well?

Your block, although older, should have the two bolt holes needed to run the gen 6 type cam retainer plate. You will also need a timing set designed for use with a gen 6 engine.

The distributor gear needed will be determined by the type of material your cam is made from. Not all roller cams need a special distributor gear.

You will need a hold down spider and dog bones if you are going to use stock lifters and your block has the provision to mount it. Or link bar roller lifters.
If you are running a mechanical fuel pump a bronze tip push rod could be needed.
New valve springs. (depends on the cam)
If you have to use a cam button you need a timing cover that is made for the use with a cam button.
The gen 6 timing set should fit.
Best would be to open the engine and see what you have and then post some pics.

I put a Comp Cams roller in my boat a few years back. Factory LS6 MK IV. Give them a call, they can set you right up with everything you need.

I made the conversion on my Gen 1 SBC, so I’m not sure how similar it is for the 454.

I bought a Howard’s conversion cam and lifters, and both are completely different than any stock roller setup. I then bought a Cloyes timing cover with an adjustable cam button. I could have used a reinforced timing cover and nylon button instead. You just need something that can be adjusted for cam free play, With a nylon button you trim it down; with the adjustable button you have a set screw and lock. The timing cover has to be stiff enough to not flex when the cam pushes on it.

ali_c20 said:

You will need a hold down spider and dog bones if you are going to use stock lifters and your block has the provision to mount it. Or link bar roller lifters.
If you are running a mechanical fuel pump a bronze tip push rod could be needed.
New valve springs. (depends on the cam)
If you have to use a cam button you need a timing cover that is made for the use with a cam button.
The gen 6 timing set should fit.
Best would be to open the engine and see what you have and then post some pics.

Click to expand...

If it's a mark IV block like stated, there won't be the provisions for the lifter retainer. Just possibly the provision for a cam retainer.

They already have a gen 6 cam, so hopefully the cam retainer provision is there. Then there's no worries about a cam button or anything associated with setting it up. It may not have a fuel pump eccentric though.

For Mark IV's there's no lifter retainer stuff used, the lifters themselves are linked together in pairs - that's all.

There are threaded holes on each side of the cam bore but I don't know what they're for, I've never seen them used on a Mark IV. I'd be concerned about the overall length of the Gen VI cam. That retainer boss on the cam would have to stick out of the bore to go in the retainer whereas a Mark IV cam is more or less flush with the cam boss on the face of the block. If the cam is longer it will change the timing gear alignment.

nvrenuf said:

For Mark IV's there's no lifter retainer stuff used, the lifters themselves are linked together in pairs - that's all.

There are threaded holes on each side of the cam bore but I don't know what they're for, I've never seen them used on a Mark IV. I'd be concerned about the overall length of the Gen VI cam. That retainer boss on the cam would have to stick out of the bore to go in the retainer whereas a Mark IV cam is more or less flush with the cam boss on the face of the block. If the cam is longer it will change the timing gear alignment.

Click to expand...

I've not assembled the parts myself, but I've been told and have read that those holes can be used with the later retainer plate, along with a gen 6 cam, which in turn requires a timing set compatible with the gen 6 cam.

I also do not know what GM originally intended to use those threaded holes for.