bobbarry

My completely-stock 72k-mile '71 270hp 350 idles very nice with the original #3663152 camshaft, but with its .390/.410 lift it runs out of breath in about the mid-range.

Along with refining the carb and timing, I was considering the extremely-inexpensive upgrade ($60 through Summit) of fresh stamped rocker-arms, but with the 1.6 ratio rather than the stock 1.5's.

This would bump the lift up to about .415/.437; still below the 350hp-cam levels, but better than the lowest-lift cam Chevy ever put in a 350, and still not taxing the flow capabilities of the stock iron head.

I've seen one person on the forum with good results from a 1.6-ratio upgrade, and basically everybody else recommending a cam/head/intake swap to any question about improving performance. Thank you in retrospect and advance for all similar advice; I recognize the levels of performance to be gained that way, and may some day do the whole package, but for now my priority is simplicity, low-cost and retaining the very smooth idle and everyday driveability.

So what I'm looking for is first-hand experience from anyone who has refined their 300hp/270hp/L48 motor's performance, or anyone who has installed a 1.6-ratio rocker on a low-performance engine and been disappointed.

Vette79C3

I did a complete top-end rebuild and installed the 1.6 full roller rockers as part of the build. I can not give you a first hand opinion on the difference between stock 1.5 and full 1.6 roller rocker upgrade but I can say I did it because it made sense for me to. It's simplicity alone to me was worth it. You do get a small increase in performance probably not noticeable. They are much easier to adjust and more accurate.

wiseman79

I've gone from stock rockers to 1.6 roller tips on 3 engines, each time I did it when changing valve seals. One was my 84 vette with otherwise stock CFI, one was my 88 blazer with stock 350, and my 78 trans am with a mild 350. I could tell a difference each time, even the blazer which had 38's. Nothing major, but a little peppier from mid range on up. I never added regular 1.6's only roller tips so don't know which helped most, the extra lift or the roller tips.

Ganey

You will get a minimal difference w/ 1.6 & your cam. 1.6 were made for tuning.
It's possible to get a day & night difference w/ a cam.

TODD C

im not positive, but wont there be a pushrod clearance issue without elongating the slots in the heads. i know its a quick swap on the engines that used self aligning rocker arms. comp cams makes a tool called the louis tool that uses a hand drill and a 5/16 drill bit to elongate the slots, but id want the heads off the engine for that.

bobbarry

Thanks! That's the kind of first-hand experience I was looking for.

I'd love to build up a stock-looking motor putting out about 300hp to the rear wheels, but I'm going to drive it as-is with minimal mods because it's just so sweet the way it is now.

glen242

What is your RWHP now? You gotta have a base line to figure any gains.