Z06-Dave

I know its a good idea to measure clearance, and I will do so before I install the heads but I want to make sure there is a 99.99% chance this setup will not cause any clearance issues before I get them milled.

2003 Z06

230 228 cam
112 LSA
Lift .592 .571

I'd like to have the heads milled for 63cc chambers for a little more compresion. Maybe it's even unnecessary?

Anyone run the AFR's with an X1 cam?

SDB

iTrader: (7)

milling the AFR 76 cc down to a 63 is a lot of milling.....I think AFR is coming out with 62cc version of 205 and 225....I would wait and use those. Call Tony Mamo at AFR (ext. 109 I believe). I milled my 225's down .036 and measured everything, but my setup is totally different than yours.

Z06-Dave

Tony is a busy guy, I don't want to bother him until I HAVE to.

I guess since I may swap the cam in the future (bigger), I should just let the heads alone, better to be safe than sorry. I can mill them later if I really want to.

Dave

PREDATOR-Z

62 cc shouldn't be a problem.
My advice is run a tight quench .040>.045 Cometic and mill accordingly.
Reverse split cams love higher compression and chamber pressures.
Try to get as close to 11:1 as possible with good clearance.
Also the less you mill the more flow you keep, that is another reason to get the slim Cometics.

BTW for every point more in SCR you get ~ 4% more hp. So let us say that you're leaving 12>15 hp on the table.

ArKay99

iTrader: (1)

You didn't say what AFR's you have. I have the 205's with 66cc chambers. If you want to go to 63cc you would only have to mill .018". Also you didn't say what advance your cam is ground at. I can tell you that I first milled my heads .010" at first and had a 224/228 .581"/.588" 112lsa at +2. I mounted the heads on .040" gaskets and the pistons were .004" out the hole. My measured clearances were .110" intake and .138" exhaust. I then redegreed the cam straight up and had the heads milled another .020". I notched the pistons .065" and had .135" intake and .137" exhaust. I guess you can make some general interpolations from that, but I would say that if you want a good tight quench, (on stock deck height) and use a thin gasket to get it, you will be very close on the intake valve with that cam and .018" milling given a +2 to +4 advance.

Of course this is all speculation unless you measure...

PREDATOR-Z

There is a guy on here that runs X1 + 5.3 stage 2E heads, I can't put my finger on his handle name.
If 5.3's fit, AFR should fit (remember .015 more deck height than stock casting.), but again measuring will tell you for sure.
Do not "if" when it comes to quench, just do it. I wouldn't go over a .045 gasket. Then mill within clearance limits. .08 intake and .10 exhaust.

Tony Mamo @ AFR

iTrader: (13)

Dave...

I'm never too busy to help out...One of the main reasons I do spend the time on these boards is to try and aid everyone using our product so their money spent will realize the greatest gains possible in each of their individual applications.

Regarding your questions, I think 63 cc's (an .018 mill as Predator Z informed you) and an .040 gasket will work very well. That should yield you right at, or slightly under 11 to 1 compression.

Concerning your piston to valve, I can tell you with a fair amount of confidence that it will clear but you will have little or no room for error in the event the engine flares up in the water box, or you miss a gear, etc. My guess is that you will have .060 - .075 or so on the intake. I would be curious as to your results. If you would consider notching (which I would recommend to be safe), I would mill the heads to 62 cc to compensate for the small reliefs you would cut into the pistons. I usually reccommend that people not wanting to notch stick with our tried and true 6016 cam (224/228). Anything larger, especially on a tighter LSA, starts to get questionable (concerning P to V), not to mention you are much more likely to tag a valve into a piston if your P to V is tight with a hydraulic roller performance motor (versus a solid valvetrain which is more stable at high RPM).

Hope this helps....

Tony

Z06-Dave

Thanks for all of your help guys...

I ordered the 66cc heads last night, talked to Tony, and decided to go with 64cc milling to be on the safe side, with .040 gaskets. He explained I'll leave a little HP on the table by only milling to 64cc's but I am more concerned with safety than big dyno numbers, it's simply not worth the risk to me.

Can't wait to bolt them on! From what hear and read, these heads rock!
10's here I come!

Dave

JG853

I have my AFR Heads milled to 61 CC. I know guys that are milling to 59 cc. I use all of LG's stuff. I have a .045 cosmetic gasket. I do not race or anything, but with that cam, I believe that you could go to 59 cc.

PREDATOR-Z

Please read ALL posts one more time. No flycut. 63 cc will be tight 59cc will require flycut.