Ok, crazy idea, I have a 351w cam which we all know is the same design as a "H.O." block. I'm putting it in a 91 block that is going to be carbuerated. Ok, here is the weird apparently never asked question...... Can I run the stock hydraulic roller lifters with the flat tappet designed cam? All I can find in the differences with the roller cams in comparison to the flat tappet cams is that the roller cams have a longer duration since the roller is more accurate. With this being the case I see no difference in running a roller lifter on a flat tappet cam. I can see the bad side of running flat tappets on a roller because it would try to cut into the higher lobe but I really don't see a downfall to what I'm proposing, obviously the only advantage is that I won't have to buy a new set of flat lifters although they are cheap, but I figure the rollers would reduce friction and maybe add a few horsepower. Ok, any ideas or if anyone has seen this done or done it themselves please let me know.....
*new* lifter question
- Thread starter Febulous
- Start date
txstang84
15 Year Member
no-the flat tappet cams are made from different materials, roller cams (with few exceptions) are made from billet, as well as the roller tips on the lifters, trying to run roller lifters on a flat tappet cam will eat up the lobes-plus flat tappet cams have a slight bevel to the lobes themselves to promote lifter rotation (even out wear patterns)...
txstang84
15 Year Member
...honestly though, the rollers don't make the cam "more accurate" the cam manufacturers of today i'm sure would take issue with that. flat tappet cams have come a long way since the 50s and 60s...hell even since the 80's! take a look at some of the newer flat tappet grinds-they have great under the curve numbers and they don't beat up the valvetrain like older max-effort cams used to.
and since the lifters themselves are taller for a roller cam, if you swapped to a flat tappet cam, you'd also have to buy different length pushrods...
and since the lifters themselves are taller for a roller cam, if you swapped to a flat tappet cam, you'd also have to buy different length pushrods...
txstang84
15 Year Member
i hear ya, i got too many parts laying around as well, but if you try to use those roller lifters on a flat tappet cam, you're just asking for metal in your oil, and a cam that's worn flat in a very short time.
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