I'm building a supercharged 383 and need to know what ratio rockers I should be looking for. I'll probably get a custom cut blower cam and Comp Hi-Tech push rods, not sure on length yet, but what about rockers. I can get a good deal on cromer 1.65 rockers, but I've heard of people running 1.7 and even LS7 1.8 rockers with success. I'm going with taller valve covers so clearance is not an issue.

 

I did a Comp ProMag 1.52:1 ratio with proform covers. Also, selected a CamMotion blower cam (231/ 240 @ 0.050/ .536/.560" lift on 110* CL/ 114 lsa). I put all the lift into the cam and run a low ratio rocker. I did run Crane SA rockers, but, the ProMags are more rigid and had larger trunion bearings. I also use an AFR HydraRev kit to load the lifters onto the cam. I recommend to verify the lifter keeper engagement on the lifter @ max lift. The HydraRev also ensures that the lifter will not float and disengage from the keeper (common with valve float). With the gm LT1, it would be better if the keeper had more "flat" engagement on the lifter. Also used a 7/16 stud with lock-tite. App... 97ss 383 - D1 - M6. B.

 

You can't choose the rocker ratio independent of the cam and springs. In general, if you are changing rockers, 1.6:1 is a good choice if it is compatible with the cam and the springs. Ratios over 1.6 on typical SBC heads get into interference between the pushrod and the head and this leads to the need to do some grinding on the head, and so on. I am not sure why you decided on the Comp Hi-Tech pushrods, I don't buy from anywhere but Manton for high performance pushrods. Good advice, good service, great product, fair price.

Rich

 

Well, I'm buying everything as a package deal for a great price so some of the stuff I will end up selling to help recoupe and save up for the parts that I want/need.

Like I said, I am just trying to get an idea since my plans are not set in stone yet.