pdd

iTrader: (3)

when i get my afr 205cc 66cc heads should i mill them or just through them on as is.

Slowhawk

iTrader: (12)

Keep them at 66cc..

HumpinSS

iTrader: (1)

why? WOuldnt he be shooting for like 11.0:1 for the street

Tony Mamo @ AFR

iTrader: (13)

If you don't live in CA or AZ I wouldn't hesitate for a minute to mill them down to 62 cc's or so....with an .050 head gasket your just under 11 to 1, with an .040 gasket your just above it. Even in the 91 octane states (which I happen to live in) I still advise a compression bump if your trying to get the most out of the head swap....it just takes a very good tuner to minimize knock retard etc., but the AFR chamber design seems to show better resistance to knock anyway. Either way you go, you will be smiling.....

Hope this info helps you out...

Tony M.

pdd

iTrader: (3)

thanks for the info

rsmith

Tony, Thanks for the reply to some of the questions we have about your new heads. My question relates to valve to piston clearance with the lifts & timing events that are close. I thought I saw posted that unmilled your heads have the valves farther away from the piston than on stock unmilled GM castings. If this is true how much milling on the AFR heads to equal stock GM casting valve clearance. I hope this question is understandable to help figure out how much milling would be needed to make valve clearance. This could help the ones that have a cam that is recommended for unmilled stock heads.
Thanks,

Tony Mamo @ AFR

iTrader: (13)

RSmith...

Your very welcome....To answer your question, you will have .010-.015 additional piston to valve clearance with an un-milled out of the box AFR 205 versus a STOCK LS6 head....but I would never NOT check P to V and assume your OK. Keep in mind, an LS6 head is 65 cc's so you would have to mill .006 off the AFR to have the exact same compression ratio....Now you have .004-.009 additional room at the same chamber volume. Hope I'm explaining it properly for you to understand.

Bottom line, the AFR 205 should yeild close to the same P to V as a stock LS6 head (and maybe a little more), and P to V must ALWAYS be checked unless you like rolling the dice with expensive engine components.

Regards,
Tony M.

rsmith

Thanks Tony, I also feel that checking p/valve clearance is a necessity, but it is best to have a handle on it going in as opposed to being on a disaster course. Seems like it could have a bearing on head gasket thickness, and possibly retarding cam a couple of degrees to help set p/v clearance when real close. Piston notching jigs for LS1 engines are hard to come by in Missouri. Computer tunes are like wise hard to get in Missouri too. What head gaskets have .040 thickness & what are .050 thick. I think the 62 cc milling of .024 from AFR heads less .010 to get even with LS6 = .014 actual difference between 62 cc AFR & 65 cc LS6 GM heads. The .050 head gasket could correct .010 if valves were too close which should work if necessary. Does angle milling ease valve clearances any and get cc lower?
Thanks for the good info on your products ~~~ looks like I will be getting milled .024 for 62 cc chambers.