Interesting thread that can at least shy people away from spending good money on maybe not such a good head..

If you have an engine that has been fine and you need to do a gead gasket or similar and find your heads under the 138.6 then there really isnt any worry..just re fit,its very unlightly to go wrong seeing as it hasnt already..

If your doing and big power engine build then find the best you can but these days id say anything over 138.5 is a result..

Niel roper and others im sure can drop valve seats and the like also so can save another life there



cheers danny