[DeTomaso] 73 vs 70 head differences

[Doug Braun]

Just a curiosity, but I was comparing my pair of 73 open chamber 351C heads
to my 70 closed chamber pair and noticed the following minor differences:

The ‘70 heads have an additional accessory mounting hole at each end of the
head (I wonder what accessory the holes were intended for)?

The ‘70 heads' pushrod holes are 1/2" diameter while the ‘73's are 17/32".
I would assume this was to increase the pushrod clearance.

Doug Braun
blue 73L #5505