Have 2 short blocks sitting in the garage and one will go in my car until a suitable replacement can be built. They're both 305's but let's not get into that debate. 350 will be in the works unless I can snag the 454 a friend has in the back of his shop. Question I have is it worth spending the extra money to put the roller motor together? If there's a notable benefit I'd do it, I just don't know the impact a roller cam has on performance and if I'd see any benefit. Heads I'll use have 58cc chambers. The roller is a 1990 (I think), flatter piston tops, missing the spider, lifters and retainers, 1 piece rear main. Other is a regular old LG4, 2 piece rear main, standard dished pistons.
IMHO, the weak points of the SBC have been a high potential for cam lobe failure and numerous places that become leaks easily. The late engines killed those problems... Also IMHO, the parts you need are plentiful at swaps and you don't have problems with lifter replacement as you do with flat tappet.
I picked up a 305 roller for 100 bucks, and I plan on using it for a long time. Only problem is my th350 converter is too big for the 153 tooth flywheel.
I got a flex plate from a 305 one piece rear main seal engine,it measures slightly over 14 inches in diameter,isn't that a 168 tooth? Anyways,it from a 91 truck 305. factory roller cam is better for real performance cam.Flat tappet is fine for a moderate cam.Some flat tappet cams are nitrided now.That and oil with a little zinc will make the cam last ok.
The last couple of Chevys I built for myself have been roller motors. I'll never fool with flat tappet stuff again for a real performance engine.
Ive heard at rpm you dont gain anything, because the roller has to speed up and slow down, so instead it just floats on the oil. believe barney navarro was one of the guys who said that
The roller lifter does allow for the use of faster opening and closing rates especially on the Chevy with it's small diameter lifter.And the cam will certainly last longer when using a lot of lift.
If it's doing that, you're not taking advantage of the roller by running higher pressure valve springs. Having raced both solid lifter and roller lifter motors, I'll not own another with a solid lifter cam in it. If nothing else, you drastically reduce the amount of maintenance attention the motor demands. I went from lashing the valves every other race, to lashing them before the first race, and again at mid-season. Solid lifters wear like a mad bastard, rollers don't. Plus, you can really increase the valve spring pressure with the rollers, which then allows you to run more radically ground cams and to turn the motor tighter. Our solid motors would top out at about 6800 rpm, with the valve train being the limiting factor. We ran the roller motors up past 7800 rpm consistently, and the only thing stopping us from turning them tighter was the rotating assembly. A roller will let you use that high dollar rotating assembly to its fullest, without the need for a rev-kit (or in our case, 'cause rev-kits were specifically not allowed), and it will continued to do so long after a solid lifter motor has worn the lobes plum off the cam.
I'll never run flat tappets again. Rollers give you free power with the cam design advantage, and there's no zddp oil concerns or flat lobes with roller engines. Less friction, less heat, less problems, more power....what's not to like? ~Scotch~
Junkyard note: I used to pillage in the dumpsters of scrap engines...All of the filthiest engines in there were flat tappet SBC's, which leaked from every joint unless put together by someone really crafty. All the cleanest were late SBC's...they really fixed those gaskets and seals and the rails of pans and covers! We probably wouldn't be out of oil now if they had attacked the obvious problems in 1956...
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