Iroc n roll

I want to test your knowledge on corvette valve covers. I want to know if the height of the old valve covers fluctuated over the years or if they pretty much stayed the same. I'm concerned with the pre-86 mostly. And also, along the same lines, can the GMPP 1.6 rocker (from the hot cam kit) fit under stock height covers as long as the oil dripper or baffles are removed? Thanks, any info would be helpful.

Iroc n roll

Also, if you guys know a good corvette board that would know this I'd be obliged if you could post there or direct me to it.

Swapmaster

Production valve covers are pretty much the same height through
the years on the SB Chevy. GM rollers will not fit under standard
valve covers and the dippers may get in the way on the taller
covers.

Buy a set of Crane or other rollers that will fit under the stock
valve covers.

Iroc n roll

Aren't the Cranes and GMPP rockers the same only one has a bowtie and the other is yellow? I know they were made by Crane.

Swapmaster

They probably are.

cfabe

www.corvetteforum.com

Vader

UROC 'N ROLL,

Yes, and no. Yes, the GMPP and LT4 aluminum rockers were manufactured for GM Powertrain by Crane Cams.

No, they are not the same. Other than the obvious cosmetic differences, the trunion bearings are heavier, the rockers are thicker in the trunion boss areas, and the webs over the valve tips and push rod areas are thicker. GM Powertrain searched for a mass-produced rocker for the LT4 and found nothing suitable that would withstand their warranty test. The Crane Gold Race rockers were close, but GM Powertrain recognized that these rockers were weak in the trunion and both end areas (basically, weak end-to-end). Rather than risk numerous warranty claims, they asked Crane to redesign the rockers for Chevrolet. Crane obliged, adding material in the weak areas and increasing the bearing sizes. The rockers are heavier than the "regular" Crane Gold Race parts you can purchase at speed shops and through mail order/web order outlets. They are a different size, and only the "good" ones have teh BowTie emblem.

Since Crane had basically acknowledged to GMPP that their "regular" Gold Race rockers have some shortcomings, I would advise using something different. Comp Cams offers a few varieties of forged CrMo steel rockers that are lighter, stiffer, smaller, and far stronger than the Crane aluminums or even the GMPP aluminum (Crane/Chevy specials). The Comp rockers are self-aligning (requiring NO guide plates), are fully rebuildable using common bearings, and are offered in both 1.52: and 1.6:1 ratios, and in both 3/8 and 7/16 stud sizes. They reportedly fit under stock rocker covers as well, although with some possible oil baffle interference (you may have to remove the oil baffles).

Look for Comp Cams P/N 1317 and 1318 for 3/8" stud sizes.

Just thought you might want to know...

Vader

...and who are you callin' OLD?

Iroc n roll

LOL...Vader my man, laying down the info. The comps look great but it just so happens that I scored a great deal on some GMPP 1.6 rockers. I was hoping I might be able to use some vintage vette covers. Some people say they run'em fine some people say they hit their covers. It's a pretty bizarre situation. That's why I was wondering about slight variations in height, but I guess most production covers are the same. It could be the lift of the cam right? Maybe guys with higher lift cams hit, while lower guys don't. Either way, I think I'll go out and get some tall valve covers