I have a 1993 F-250 4X4 with a 351w (5.8L). I'm planning to rebuild the engine soon and would like to put in an OEM roller cam to pick up some pulling power. I was given an OEM roller cam, but I don't know if it's for a 302 or a 351. Can someone tell me what number to look for on the camshaft and which OEM cam is best? Thanks.

 

There are no numbers that will tell you anything, you're going to have to measure the cam. That's easy enough though with a good caliper, just measure the cam lobe base circle and peak, the difference is the cam lift. The F4TE truck roller cam produces 0.263" lift on the intake lobe, 0.277" on the exhaust lobe. If you get less than that you have the base 5.0 roller cam.. and that you want to throw away because it's smaller than the flat tappet cam in your motor now.

Now.. all that said, there are two ways to put a roller cam in this vintage motor, the first used the factory roller cam assembly but requires drilling and taping some holes for the spider in the lifter valley, and this has to be done before the cam bearings are installed.
The other method doesn't need any block work but involves spending a chunk of change on linkbar roller lifters.. which are often in the $350-500 range.

Finally I'll add that you don't need either any of this to get added performance from this motor, Crane makes a flat tappet cam(Crane 444232) that produces outstanding TQ gains along with much better midrange power.. when combined with a full exhaust system of course, but that applies no matter what cam you use.

 

If you have the cash to spend for the aftermarket conversion, a good roller grind will outperform a flat tappet. It will have a better torque curve, smoother idle, better drive-ability and economy, reduced friction and doesn't require as much lift or duration. Or, if you can find a used 5.8 roller block for your rebuild, you'll be set.
I agree about the aftermarket flat tappet as well, and it will be a lot cheaper and easier than a roller cam in your case. I'm just a big fan of roller cams, but either way works. Regardless, if you're doing a rebuild, I wouldn't use an OEM profile - but that's just me.

 

Hmm...a donated mystery camshaft. Yeah...that's one part I wouldn't use.

 

Those are the kind of donations I graciously return.

Ray

 

Miked the cam - it's the F4TE. The exhaust had been modified when I bought the truck - dual exhaust, no cats, and glass packs. I'm thinking about getting the shorty headers, but I really don't need the truck to be louder than it already is. This engine rebuild is going to be on a really small budget (I hope), so a new cam is out of the question (I hope).