i think ill need to flycut my stock pistons. im milling my afrs down to 60cc. then im installing a .045 cometic gasket with pistons .008 out of the hole. cam is fm11 228/230 .585/.595 on a 114lsa. just wondering how deep i should notch the pistons. pat

 

Pat, I think you may be ok. We did an AFR setup recently that had the heads milled .024" and we used .040 Cometic gaskets. The cam was a 224/228 .581/.588 114+1. We measured .094" on the intake and .125" on the exhaust. Since you are using a .005" thicker gasket that should put your seat height pretty close to ours. You can still go about .014" on the intake so I would measure it before you cut. It would be a shame to have the heads milled and then have to give 2cc back to cam. I have read that minimum p/v is .080" for the intake and .100" for the exhaust on these motors/heads/valves. I'm interested in how you make out. BTW, I haveread that you can take out up to .100" on the pistons and stil be ok. Watch out for hotspots though.

 

how do i measure it???

 

You need to take a pair of springs off and put in a pair of low tension springs. I got a set from Pace performance. I think Summit has them also. They are about $6 a pair. You'll also need a dial indicator and stand for it. Again Summit or Pace. You'll need a spring compressor to get the installed springs off. Be careful when doing this as a mistake can send a keeper into the 5th dimension. Once you have the light springs on you can put a gasket on and place the head on the gasket. Tighten the head down with a few bolts, not tight, just enough to flatten the gasket. Your cam should be in and degreed along with the lifters and pushrods for the cylinder (usually#1) that you are measuring. Also have your rockers mounted on the pushrods, but only tightened to ZERO lash, no more. I recommend doing this with the gasket on since your pistons are out of the hole and you won't be able to move the piston past TDC without it because it will top out on the head. While you are SLOWLY turning the crank in the direction of run take your finger and start pushing the valve down by hand and letting it up. At some point the cam will start to lift the rocker and push down on the valve and the piston will be getting closer. As you keep turning and pushing you will find the point that the valve and the piston are at the closest. When you get to this point set you dial indicator as close as you can to the top of the valve point on the rocker and zero it out. Then push down on the spring until you contact the piston. The dial indicator will read the p/v.

 

my diamond forged -2cc pistons