So ive decided to bulk up my trucks motor a bit and I wanted to start off by swapping out the stock flat tappet cam and looking into buying a roller cam which I hear is better. This being said would I need new lifters also when I swap out cams?? Here's the cam im looking at COMP Cams: Hydraulic Roller

 

If you're changing cams then you need new lifters. The reason for that is the lifter and cam lobe wear in as the cam turns, and they are compatible with each other once they've run together for some time -- but they are not compatible with parts from another lobe/lifter combination without some work.

Flat-tappet and roller lifters are another issue altogether. The flat tappet's lobe-bearing surface is, well, flat (for all intents and purposes). A roller lifter has a roller that bears on the cam lobe. The cam lobe is ground to be compatible with the type of lifter used with it, so you can't mix flat tappets with a roller cam or roller lifters with a flat-tappet cam.

As far as which is better, that depends on whether the profile you want is available in that type of cam. For my nickel rolling contact is preferable to sliding contact so, even if the same profile is available in both types, I'd choose the roller cam too. Cam profiles can be a lot more radical with a roller cam than they can be with a flat-tappet cam too, even for near-stock engines, so that is another point in their favor.

Hope this helps.

 

Thank you! Because ive been reading a few other threads and for these 351w it looks like the best place to start is with swapping out the factory cam...apparently its pretty ****ty from what im reading

 

Your motor is not setup to use the factory roller cam assembly which can be obtained cheaply on the used market or from a scrapyard, to use a roller cam in your motor without completely stripping it down you would have to buy the expensive link-bar roller lifters which makes converting your motor a $600-800 expense. Now.. roller cams are definitely better than flat tappet, the cam ramps are more aggressive so these cams make more power, and they vastly reduce internal friction which also puts more power to the ground. But you can have 95% of the same power gains with a similar grind flat tappet cam and it most likely won't exceed $200 with lifters, so you really got to want a roller to justify the expense. Note.. if you strip the motor down the valley can be drilled and tappet to accept the factory spider(lifter hold down) assembly and then you can use the factory lifters which only cost $125 a set brand new. This procedure often requires replacement of the cam bearings however and that's why it's not something that the average guy can do in the driveway.