I have some original Navarro heads going on a '49 Mer c flatty. The guy cleaning them up shaved off a few thousands. Should I use doube gaskets? They were already higher compression than stock. Also, would you advise that I use copper? Any sealer? Can't remember much from the 50's/60's! Thanks!
Most of these heads were not that high on compression to start with. Just make sure you have enough valve clearance. When installing I use Copper Cote spray, it has a tackiness to it, spray both sides. Wait a few seconds and install. torque as you would normally. You shouldn't have any problems..--TV
Put some clay on top the valve, screw down the head {with no gasket}, turn the motor over. take off the head and check clay..How I do mine...
You can't have too much compression (ratio) in a Flathead-that's the main thing in giving the feel of power. As long as you've got adequate clearance over the valves and pistons, go for it.
You cannot have too much space between piston and head or engine will have poor performance and sensitivity to pinging regardless of compression... just like a SBC! Also, obviously too little will result in instant destruction. Put on heads with no gaskets and rotate engine a few times by hand. If heads don't move you have enough not to break parts (about 050). Next, gaskets in, tighten down a few nuts, rotate wit clay or aluminum foil balls stuck to piston tops. Measure crushed area. You want about 050...more and you need to mill a bit! Gasket crush in tightened condition is very small factor. Use used gaskets if worried.
The combustion process in these requires turbulence, generated by the rising piston forcing the mix out of the quench area above piston into the area that remains open between piston and valves...lackof this needed turbulence affects all sorts of performance factors. Chevy lost rack of this in the 1970's, and produced lots of 350's that could be outrun by 1200 cc imports due at least partly bad piston and chamber design...
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