Dual bolt pattern - when discontinued?

[aribert]

I know the dual bolt pattern started in '66. When did the smaller pattern get discontinued?

 

[xctasy]

I know the dual bolt pattern started in '66. When did the smaller pattern get discontinued?

We recapped this one about 5 years ago. Its a difficult one to answer, as there are no hard and fast rules with Ford i6's.

Technically, in 1980 when the low mount starter block was being phased in, the blocks were no longer capable to fit pre 1967 trasnsmissions.

All 1968 to 1980 blocks are small pattern capable if the flywheel is hooked up, and the block flange is redrilled for bolts and dowels with the older 2.77 transmission in place.

Since eventual destinations of any given Ford 170 or 200 engine varied, both sets of holes were in the casting from 1966 to 1968, but the smaller set were not reliably drilled in after 1968. Some cars up to 1972 still had them drilled.

 

[aribert]

I'll answer my own question for others for future reference. Just bought a '78 200 engine. Block has the dual mounting pattern. THe small pattern, as used for the 2.77 trans early on, is also used for the C4 auto trans mtg (thru atleast '78). Some searching after I posted the original question, implies that the dual pattern exisited from '66 forward for all high mount starter 200 blocks.