X vs J- flow differences?

toolmanmike said
It would be interesting to find out what the engineers at Mopar did to create the casting differences. Next time I see Radar (Roger Luctenberg) I will ask him if he did any porting for the OEM. I know he was on the B1 team and when he worked at Gary Ostrich's shop they did experimental work for Chrysler Corp.

I have ~’73 to ‘79 Small block development correspondence between Tom Hoover and paid consultants’ “experimental work”.

For small block heads, it’s mostly X head, street T/A, race T/A, W-2/2.5/3. There is a “360 production” head in the notebooks from 75 or ‘76. IIRC, the casting # wasn’t listed.

I believe the effort/development was focused on whatever classes Chrysler (Hoover) wanted to focus on.

Below is a 894 X-head BTW. Note tested by Mullen in early 1970. Attached to the 1973 document for reference.