I just had a pretty simple question about the cams mentioned in the title. I was curious what the prerequisites are for an engine to be compatible with a roller cam vs flat tappet cam. I plan on trying to build an engine and am trying to make sure all of my plans will work together.

Thanks guys!

Pretty simple really.. Roller cam engine block or retro fit roller lifter kit. You must have one of the two.

Retro fit roller lifters in 1955-86 engines, these lifters are not cheap.

87-up blocks are roller blocks. The car engines got the roller cam, truck engines did not get a roller cam until 1996, but most truck blocks came with the bosses in them, some was tapped, some wasn't.

If you have a block that can use factory roller setup, you will need the spider, dog bones, lifters, cam retainer plate, pushrods from an OEM roller engine.

If it's a truck block and bosses are not tapped.. You can drill and tap those to accept the OEM style spider, and retainer plate. Then use factory roller lifters, dog bones, etc

Flat tappets are an older design, which is why the older blocks are "made" for flat tappets/cams. "Flat" tappets actually have a slight crown on the face, or are convex. This allows the lifters to rotate freely during operation. This spread the wear over the entire lifter face, and possibly reduces friction. There is also a slight tilt to the face of the cam's lobe, which causes the lifter to rotate and keeps the cam pushed to the rear of the block.

Roller lifters are taller, and cannot be allowed to spin, due to the roller. When installed at the factory, the block was revised with a taller boss to support the longer lifters. The top of the boss is machined flat for a "dog bone" shaped piece that fits over two adjacent lifter to keep them from spinning. 8 dog bones total, holding the 16 lifters. Next, the center of the block has three bosses, tapped to hold down the "spider", which is a sheet metal piece with eight arm to hold all 8 of the dog bones in place. Finally, since the lifter-to-cam interface is flat, or no tilt like the flat tappet, the lifters do not "hold" the cam toward the rear of the block. Therefore, the cam now has a retention plate bolted to the block behind the timing gear to keep it located front/rear. Factory roller cams, and aftermarket replacements, have a step machined in the front face of the cam for the retainer plate.

Aftermarket, "retrofit" roller cams are made to fit blocks made from either flat or roller cams. Which is, it does not require any of the roller cam specific features on the block. The lifters have a bar pairing two lifters together. The bar slides side-to-side to allow the lifters to go up and down independently, but keep from rotating. To keep the cam in place, there is a button installed after the timing gear which pushes against the timing cover to keep the cam in place in the block. And behind the timing gear is a torrington (flat) bearing to prevent the gear from wearing against the block... from the higher force the button is applying, than flat tappets would. These aftermarket cams do NOT have a step milled into the front of the cam.

If your block is made for a roller cam, you can use either factory or aftermarket style cam and lifters. You can mix and match factory cam with aftermarket lifters, or vice-versa.
If your block is made for flat tappets, you must use an aftermarket cam AND lifters.
Of course, you could use a flat tappet cam/lifters in either block. But, since motor oils are lower on ZDDP (zinc additive) these days, and ZDDP is a friction modifier that reduces wear on flat tappet cams, going with a roller cam is more recommended.

Well its all in the combination and not any single part that optimizes power. As u go larger in duration the low RPM power tends to sag without an increase in compression. But keeping the same duration numbers and changing over to roller cam it depends on the full duration numbers to compare them. A short flat tappet cam with <270 degrees duration is gonna be hard to beat - bread and butter cam for street driven car for decades. This is because the flat tappet accelerates opening on the lobe ramp faster than a roller cam. The legacy mushroom flat tappet cams where the mainstay of even NASCAR. But the roller cam has greater velocity opening on the lobe ramp. And >270* duration it starts to make more power than the flat tappet lifter cams.

So for what u are asking u need to look at how u want to drive/race the car and what trans/gearing/manifolding/exh/smog equipment u decide to use.

A 2.73:1 axle even with a 700-R4 trans is gonna need help off the line. Im thinking a short cam here well under 270* full/advertized duration and like on a 112lsa. Its gonna run out of breath around 5,500rpm but on a street car but it would be much, much more fun to drive than anything larger. Comp cams has lots of short flat tappet cams that are whole lot cheaper than a retro roller cam. Now u can find short retro hyd roller cams but the only advantage would be u wont have to worry 'bout wiping a lobe on break-in. I really like the Comp #12-256-4 or maybe the #12-388-4 for your car. And the Crane Cams #113501/113502 or maybe the #113901/113902.

Again its the combination that will optimize or even reduce power if done correctly or incorrectly. A better intake would help but the TBI intake by Edelbrock is not list as an application for your camaro by Summit for some reason - dont know why but it would match up to a short cam nicely. That and a set of long tube headers like 1 & 5/8" diameter would match your power band well with that cam. BTW a single 3" exh pipe and high flow cat aint all that bad - not the best but thats why those dual pattern cams i mentioned with the added exh duration work well in your car.

Thats enough for now and if u have more specific questions just ask.

Swapping from a flat tappet to a roller cam is more expensive because of the cost of the lifters but a roller cam is a much better design.

There's less friction but the amount of friction created by a flat tappet may only be seen as a small difference in HP on a dyno.

The roller cam design allows for more aggressive ramps to give more area under the curve while keeping much of the cam grind specs the same. The ramp design still has limitations based on the lifters used. OEM style roller lifters have a very enclosed roller wheel compared to aftermarket lifters. The open wheel design exposes the wheel more to climb steep lobe ramps.

Roller cams and lifters can easily be swapped around. With a flat tappet cam, once the lifters have worn into the cam lobe, those lifters can only be put back on the exact same lobe they came off of. A bad flat tappet lifter can be replaced with a new one on a flat tappet camshaft but a new or different camshaft can not reuse old lifters from another cam.

You can buy a new or used roller cam and install new or used roller lifters onto it. Neither wear into each other.

As mentioned above, a roller block will have a guide which keeps the OEM style roller lifter from turning in the bore. A non OEM block needs lifters that use a link bar to hold 2 lifters together to keep them from turning in the bore.

Although the roller lifter body is slightly taller, pushrod length is the same however as with any cam or head swap, proper valve train geometry checking is required.