Rocker arms: roller rocker, stamped steel roller tip, or stock

[G-NUT]

Any thoughts on what would be best; roller rocker, stamped steel roller tip rocker, or stock type stamped steel rocker?

Stock '85 350 with World Products S/R 170 intake runner, 67cc heads, mild 'RV' cam, performance rebuilt q-jet carb, mild-length headers, th400 trans, stock torque converter, 3.73 L.S. 10-bolt rear axle.

[mattfranklin]

Engine Masters did a great back-to-back-to-back dyno test for many combinations. Rollers gave zero power difference. The only thing that made more power was picking a higher ratio, either for stamped or rollers. I recommend watching the video. Very educational. I'm using Crane ductile stamped in mine, stock ratio, because I'm keeping stock 1970 Corvette parts and specs.

[SunSoaked]

Stay with stock or go full roller. As stated, you wont gain any significant power unless you change ratio. You will reduce friction and reduce wear to some degree, mostly in the valve guides/stems.

[G-NUT]

Originally Posted by mattfranklin

Engine Masters did a great back-to-back-to-back dyno test for many combinations. Rollers gave zero power difference. The only thing that made more power was picking a higher ratio, either for stamped or rollers. I recommend watching the video. Very educational. I'm using Crane ductile stamped in mine, stock ratio, because I'm keeping stock 1970 Corvette parts and specs.

Got it pulled up and I'm about to watch it while eating lunch. Thanks for the reply and insight.

[G-NUT]

Originally Posted by SunSoaked

Stay with stock or go full roller. As stated, you wont gain any significant power unless you change ratio. You will reduce friction and reduce wear to some degree, mostly in the valve guides/stems.

Thank you for the response. I really appreciate it.

[GASoline71]

I have stamped roller tip rockers in my 350 right now. I got them on a good deal from a buddy who bought them and then never used them. Waste of money if I would have bought them new... no significant gain of any kind, and they are noisy.

Full rollers or nothing. But with a mild "RV" cam and those heads... stock stamped rockers would be just fine.

The video from Engine Masters does show a significant gain with roller rockers after switching to a 7/16" screw in stud over a 3/8" screw in stud. The 7/16" studs are less prone to deflection at higher RPM's. So if staying with 3/8" studs and making any kind of higher RPM pulls... it'd be a good idear to invest in a stud girdle.

Gary

[mattfranklin]

Originally Posted by GASoline71

The video from Engine Masters does show a significant gain with roller rockers after switching to a 7/16" screw in stud over a 3/8" screw in stud. The 7/16" studs are less prone to deflection at higher RPM's.

Gary

Yes, I forgot the deflection part. Loved that vid.

[Coley]

Yeah...very good video, thanks for sharing on that.

I have heard about the advantages of the 1.6 rockers....even just having them on the exhaust, although I don't have any experience with that.
I think some guys have added that 1.6 advantage to basically an otherwise stock engine and cam and ended up with a slightly higher valve lift and more power as a result.

What I would be curious about is if anyone knows if a 1.6 rocker can be run with the stock valve cover?....definitive info.

All good
Coley

[mattfranklin]

Originally Posted by Coley

Yeah...very good video, thanks for sharing on that.

I have heard about the advantages of the 1.6 rockers....even just having them on the exhaust, although I don't have any experience with that.
I think some guys have added that 1.6 advantage to basically an otherwise stock engine and cam and ended up with a slightly higher valve lift and more power as a result.

What I would be curious about is if anyone knows if a 1.6 rocker can be run with the stock valve cover?....definitive info.

All good
Coley

Back in the day people used to use Plasticine clay to check for piston to valve clearance with high-lift cams and domed high-compression pistons. If no one responds with a solid answer about stock rocker covers, I think you could put a couple of globs of it on a few rockers, turn the engine over a few revs, and see how close it gets to the cover. And then know that in a running engine it would be tighter when the lifters pump up. Also, there are thicker valve cover gaskets available to help with clearance.

Also, on the rocker issue, the official Chevy Power Catalog (in my late 1980s edition), suggested trying higher ratio rockers. They also said try them on intake alone, exhaust alone, and then together and see what performed best.