Shaving N42 head maximum amount without cam tower shims?

[MX500]

I'm shooting for a compression ratio around 9:1, up to 9.5:1 would be nice, but not necessary. I plan on boosting my car up to about 10-14 PSI in the future so I can't go too high on the compression. I have a spare L28/N42 longblock from another project so I'm not worried about taking too much off this head. How much should I shave of the head to achieve this ratio? .040"? Will I need cam tower shims if I shave the head this much?

 

 

 

 

Ideally, I would like to shave the head the maximum without needing lash pads or cam tower shims. I only have ~90,000 on this engine so the timing chain and everything is still relatively fresh. I'd like to do this the most cost effective way possible. I've heard Norm (12 second SU dude) mention people running up to .080" shaved without cam tower shims with new timing chains. I don't want to go over 9.5:1 compression, so I don't think I'll need to go that far.

 

 

 

 

What is the maximum amount I can shave the head without using cam tower shims? Will I need lash pads? I need some more details on this. I'm pulling my head off tomorrow and taking it to the machinist friday so I need help as soon as possible.

 

 

 

My set up:

1970 240Z, 1977 JDM L28 with N42 head (NO INJECTOR NOTCHES!), Comp cams 280S grind (.460 lift 280 Duration Intake and Exhaust), 6-2-1 header, 3" exhaust, 1977 4-speed, 280ZX turbo clutch.

[stprasinz]

I was told .007 of max before needing shims.. never tried it though... I thought the tensioner would be able to take up the slack, and as long as you could get the cam timing correct.... I wouldn't see why you couldn't. But back to the origibal statement I made... I was informed a max of .007 before shims needed... But .015 is the thinnest shim I know of? shave .008 off and shim it .015 makes less sense than shaveing .010 offf and calling it good to me...... Oh well... good luck.