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Rtc 8 Question

J

jr72

Member
I am putting an Rtc 8 head on my Hemi. What can the head safely be milled before having clearance problems. Piston is zero deck with f275 cam. Haven't decided on rockers yet.
 
I have a .280 lift cam in a hemi block, with an rtc-8 head that was milled .080, using a .009" thin head gasket, and the piston is .020 in the hole, I have no issues with piston to valve clearance with this engine. It all depends on how thick of a head gasket you use, and how much you mill the head. If you go with ratio rockers, you would not be able to mill as much off the head or you will have contact. You can mill the head however much you want then mock it up and put some clay or playdoe on top of the piston and rotate the engine over by hand then pull it apart and measure the clay to see how much piston to valve clearance you have, then use headgasket thickness to get enough clearance. .030" seems to be the minimum most are comfortable having. You can also just cut valve reliefs in the stock piston, but gotta be careful and dont cut them too deep and compromise the strength of the piston top. Just my opinion, I have built quite a few of these engines using several different combo's and just about anything can work with the right machine work and patience.

I doubt you will run into clearance issues using the F275 cam as long as you don't mill the head flat down to the fin and dont use ratio rockers
 
Also another thing to check is the proper push Rod length when milling the head down, you might have to use shorter lifters or a shorter push Rod to maintain proper geometry....
 
Assemble with chosen parts, measure valve clearance as described, then mill head, instead of guessing and compensating with thick gasket.
 
Thanks for the information. I have built several stock class engines, This is just my first time trying, I guess you would say mild modified.
 
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