Raising Compression Ratio w/ Head Gaskets

I would like to raise my compression ratio, currently calculated at 8.7:1 to ~9:1 if possible. I have a 289 bored 30 over and flat top pistons with small valve reliefs (stock compression ratio - 9.8:1). I have switched out the stock heads (54.5cc) to a later year with 64.5cc.

I have no plans to tear the bottom end apart.

Does anyone know who makes the thinnest head gaskets and should I also mill the heads to achieve this?

Thanks.

Not sure but I think that the average max gain by thin gaskets is about .5. Same for milling heads but then you get into milling the intake to fit and then valve train geometry stuff. Possibility of valve to piston problems too.

you will get the best results if you go back to early '60's heads; either the 55 cc oreven better, the 46-49 cc heads. hipo heads with flat tops were 10:1 motors with the 46-49 cc heads stock. all oem heads have the same porting potential, its just that you must remove more metal in the ports of the early heads.
[addsig]