Roller Rockers

[truckster]

I'm getting close to buttoning up the Vortec 5.7 I'm building for my Blazer. It's a .030 overbored block, decked just enough to clean up the mating surface (about .002), RamJet 350/HT 383 camshaft, new Vortec castings relieved for larger springs. I'll be running a Quadrajet and HEI. As I'm putting it together, I started thinking about roller rockers. The ones I'm considering are the 1.6 Competition Cams 1418-16 Magnum self-aligning roller rockers. I have a few questions for the experts on the board:

1. Comp Cams claims a 15-30 horsepower increase with these rockers. Is that realistic? Can I expect a similar increase in torque, especially in the useful range?

2. Are these good rockers? Is there a better value I should be looking at?

3. Can I use these with my stock pushrods and valve covers? (Comp says the valve covers will clear)

Thanks

David

[AcampoDave]

When I googled those rockers I saw roller TIP rockers. They still use a ball and socket type trunion. I put that style (1.5 stock ratio) on my stock 283 because they fit under my scripted valve covers. (The full roller style necessitated the need for the tall covers which was a no go for me.) I did notice a smoother quieter idle and I felt a bit more torque at the moment of engaging the clutch. But nothing remotely close to 15- 30 h.p. My stock stamped steel rockers were very old and I'm sure that once wear and flex were factored in that they probably were not achieving the same valve lift as the new chrome moly roller tips. Mine were not Crane but rather a lesser known American made brand whose name I cannot remember now. They were a bargain and I am still happy with them. But for more performance a FULL roller rocker would be the ticket. Just remember that you would need tall valve covers too.

[truckster]

Thanks for the reply. I realize that they're not full roller rockers. I'm going to be running the serpentine system from the Vortec donor, so I don't think tall valve covers will fit.

I wonder if the 1.6 ratio makes that much of a difference.

[Marv D]

I would definitely NOT waste $ on roller tip rockers. The friction is mostly in the pivot ball, not that little contact across the valve stem tip. Besides,,, @ normal vortec / street cam lifts your only going to gain 0.030" valve lift.

If you haven't measured and PROVEN for a FACT that you have valve to piston clearance for the extra 0.030" lift,,, I'd be cautious. Remember Murphys second rule of mechanical relationships...

[Ironangel]

I've been running these in my big block with no ill effect. In fact, when a bent pushrod guide caused a pushrod to break the roller tip did not eat up the valve tip. I don't think they lend to 20 more pony's but do reduce a percentage of wear and friction on the valve tip. With that said, Marv is correct in making damn sure your piston to valve clearance will allow their use. They should be looked at as wear item and not a HP or torque gain item. ~Ghostrider~ http://www.jegs.com/i/COMP-Cams/249/1411-16/10002/-1

[Tom]

Originally Posted by truckster

1. Comp Cams claims a 15-30 horsepower increase with these rockers. Is that realistic? Can I expect a similar increase in torque, especially in the useful range?

2. Are these good rockers? Is there a better value I should be looking at?

3. Can I use these with my stock pushrods and valve covers? (Comp says the valve covers will clear)

1- Nope.
2- Yup.
3- You need self aligning rockers to use the stock setup

[GRX]

Well, changing from 1.5 to 1.6 ratio will increase both lift height and valve opening speed. Debatable whether that equates to 15-30 HP improvement. Also keep in mind you might need to elongate push rods holes in the heads going 1.6.

Agree that roller tip are largely a waste of money, for the reasons mentioned above. If you really want to eliminate friction shell out the bucks for full roller and poly locks.

[YoungPup1977]

I put a sticker/emblem on the side of my truck stating it has 550 HP......I do not even have roller rockers.....