273 commando Build

Jumping in....on my 273 Commando's and a recent purchased low mile 1966 273 with a casting # 28xxxxxx....it does show up in a book as correct for a 66-69? block . Now both my hi-po's were apart but of a stock bore hence the low mile 273 2 barrel motor purchace.
I wanted to go with the later cop 318 heads - 83/86 #4323345 which are 1.88/1.60 and flow at 75cc...sure some notches....sorry can't add anything to the gasket issue....
The 2/3/65 block is the original to my S car and was cleaned up for a stock rebuild some 30 years ago. 20180410_182808.jpg 20180411_124337.jpg 20180410_192724.jpg plugs. The 28xxx block came out of a 1966 Valiant wagon...