tyler72

Hello, I have been having a major problem with cams failing in my 347. I have been running flat-tappet cams, but am now wanting to switch over to a roller cam so that I don't round a third flat-tappetcam off. The problem is that I have a 72 model block, which doeesn't have the provisions for the roller cam. It is my understanding that you can retro-fit in a latemodel Roller spider, H-bars, and lifters to an early model block. There are two ways to do it. First of all, you can drill and tap the block in the lifter vally to accept the spider, or youcan get inserts for 2 of the oil drain holes, and drill 2 new holes in the spider itself.However, there is one other difference.Supposedly, there is one other difference in the blocks. The lifter bores are slightly shorter on the older blocks, so a small base circle cam is required to prevent the lifter from coming too far out of the bore which would possiblymake the H-barfail, or come comepletely off, and therfore ruin another cam/engine.My question is, has anybody onhereever done this retrofit??? I need to know what all it entails, and if it is actually worth considering.

Joel5.0

Nope.....it's not worth considering due to the small base circle cam you would need to install. The best alternative is the use of the link lifters, a little bit pricey, but the best alternative to prevent more camshaft failures, and use the regular base circle HR cam.

HACKGT350

if i were you i would find a roller block and swap all your internals and everything over get it machined for everything to fit and be done with it. also how are you breaking in your cam? and did you replace your lifters everytime it ruined your cam

GT350

Sorry to say your not doing the cams correctly, its not like the old days on motor break-ins, times have changed and maybe your behind? I had to learn the new also, I had the same problems, until I found the solution. If you want I'll tell ya.