hey everyone. I finally have scrounged up enough money to upgrade my rockers to full roller rockers. My question is: for my motor (summit racing aluminum heads with max valve lift of .480 and crane 2032 cam with duration at 270 int./276 exh and lift at 0.452 int./0.465 exh) would it be wise to do 1.5 ratio on intake and 1.6 ratio on exhaust? I had someone suggest it, but wasn't sure if that would be a big help to my engine or my quest for more power. I also have an Accel base and SLP runners which I plan on port/polishing in the future. Thanks for any and all help!

 

Do the lift with the cam, IMO. Now you are talking full rollers, not roller tips, right? Either way, if you're changing cams, get the lift and profile you want, then run 1.5/1.52 full rollers. Should be less side movement on the valves.

 

Cam is important, yours isn't maxed out, even more important is what kind of porting do the heads have. It may be better for you to go 1.6's all around. Whoever you bought the heads from should be able to give you some advise (unless it's just a retailer, in which case you need to speak with the manufacturer). The cam manufacturer could help with this as well, I personally haven't had a great deal of success with Crane's tech, but it's been awhile.... worth a try since you already have the cam and the heads. Keep in mind that a good set of springs should be included in your swap budget even if you decide to stay with 1.5's.

 

You stated the max lift on your heads is .480. If you were to switch to 1.6 rockers, you would be beyond that, .483/.496. Otherwise, I'd say go with the 1.6's.

 

ok thanks guys. i'm going to go with the 1.5's to be safe. its not a race car and i'm not an engine builder. I have talked to summit with regards to their heads and it would require new springs to make 1.6's work, and new pushrods. I think this will be safe for the build of the engine, and if i ever want more power from this platform, i'll look into better heads/cam. thanks everyone