whats the stock thickness for the gaskets on a 289? the ones on here look huge almost like someone put 2 under each head? someone told me they were .045 ? whats the thinnest i can rn without bashing anything up?

 

Uh- if the previous owner did that - i would suspect either a warped head or block. The double gasket trick is the ghetto fix versus a deck and mill.

Be prepared for a trip to the machine shop before just re-installing them.

Why are you going in there?

 

nah i looked after i pulled one off it was just the outer edges of the gaskets flaring out - :/ oh well. - why was i going in there? head swap :| gt40p's

 

I wouldn't go over .040, otherwise quench gets too large and you'll detonate. That's not true of a built engine that has negetive deck clearance, where the piston pops out of the block at TDC so you have to run a thicker gasket. On a stock engine though, you'll have several thousandths deck clearance + gasket for quench.