flat tappet cam in magnum motor?

Please forgive me if you already know all this....

There are oiling issues when you replace roller lifters with flat tappets. The top end pieces (rockers, etc.) on a Magnum-head motor get their lubricating oil from the pushrods, which get it from the lifters. Unlike the L-A motor, there are no oil-supply passages in a Magnum block to transfer oil to the heads from a hole in the block, through the head gasket to matching holes in the head, with oil for the rockers going up through the head to the rocker stands.

BUT, I've read several places where you can use Jeep flat-tappet hydraulic lifters and longer pushrods (the roller lifters are taller) and still oil the top end that way.... through the pushrods. Seems the Jeep flat tappet lifters have the required oil holes in the pushrod cup to feed oil to the pushrods.

Be aware that the lack of zinc in motor oil these days has created longivity problems of monumental proportions for flat tappet cams. This can be dealt with by using ZDDP additives and/or buying oil that still has anough zinc in it, but it's not always easy to find out which oil has what. Ignore it, and your cam may develop flat lobes sooner, rather than later...

I'd think twice before going to a flat tappet cam, with the oil problem that exists today. Hydraulic rollers are maintenance-free and have profile capabilities (because of the rollers) that you can't duplicate with a flat tappet setup. No, they're not the ticket for full-race motors, but for a street/strip car, they have a lot of good points, I think, one of which is that the zinc problem doesn't affect them... at all.

Good luck with this.

Bill