Rebuilding a 65 273..I need some help.

AJ/FormS said
from; Large valved 273
"See here for a 675 chamber on a stock 273 bore; you can see the shadow line of the overhang of the chamber. (The white disc is a simulated 2.02" valve head.)"
Here you can see the distance between a 2.02 and the 1.5 exhaust valve is pretty far apart; looks to be ~.200?
An .188 is only .07 smaller on the radius or a tic over 1/16 inch. I think it's easy to see that 1/16 off the cylinder side of the white paper disc is still not inside the bore, even if you add the .030 for half the overbore
In other words your bores will have to be notched even for the 1.88s.

View attachment 1715860798

Yup. I'll stick with the 1.78 as long as they aren't sunk. It runs perfect so I assume they freshend up the heads when they rebuilt the engine. This is all I have to go by as to what was done to it. An engine tag.