I'm running the PRC 215s (60cc) with the MS4. I'm about to go in for a tune before long and I want to do everything possible to get the most out of my stock bottom end. Right now my pistons are untouched. Would it be worth pulling them again to flycut the pistons and mill a little off the heads? I think right now I'm just a little over 11 to 1. I'm leaning more towards no but I thought I'd ask. Thanks

 

That cam moves a lot of air, so yes I think it would be worth it to shave the Heads a little. Would make a good combo with that FAST intake too.

 

each 1 point increase in compression is around 3% increase in power.

 

What head gaskets are you running? Where's your quench?

 

Did you measure your PTV when assembling? Flycutting isn't going to get you more power (actually maybe a little less due to lower CR) but it will ensure your engine will run safely and reliably. If you didn't measure, I'd say yes, pull them because that's a big cam and if you went with cometic .040" gaskets, you probably have very little PTV.

If you measured and the measurement is good, I'd say leave it but I value my time A LOT. Also, milling will increase your CR but then you will need to flycut and that will decrease your CR so the 2 may kind of balance each other out making it pointless to do.

 

If I remember right they were .040 MLS gaskets. I didn't measure. TSP said everything would clear.

 

If they were Cometics then they probably were. If they were GM gaskets then they are .051, and at that point it may be better to flycut. I believe the additional quench will negate the slight loss of compression (which you COULD make up for by going 59cc)

The only question is where will your DYNAMIC compression be at that point. Sounds like its time to get on the horn and talk to Matt or Aaron....

 

As it stands, if you have a Cometic .040" in there:

Static Compression Ratio 11.62:1
Dynamic Compresion Ratio 8.48:1

Flycutting .080" (which is equivalent to ~1cc) and a mill down to 58cc would net you:

Static Compression Ratio 11.79:1
Dynamic Compresion Ratio 8.60:1

So a little bit of a bump.

57cc would be ideal:

Static Compression Ratio 11.96:1
Dynamic Compresion Ratio 8.71:1

 

yes to both. piston to valve clearance is good. and these engines love compression, like Jake suggested 57cc would be nice. puts you right at the optimum dcr for pump gas with minimal to no timing adjustments needed and the tight quench will help you to resist detonation. setting it up this way doesn't produce much power on its own, but what it does do is allow you to extract the full potential from your setup. efficient combustion events = more power = good.

and make sure you check ptv when you're putting her back together, both with an indicator for depth and clay for radial clearance!!!!