I had thought that prior to 1970, service replacement blocks were cast and prepped (along with being renumbered) for their intended application;
eg: a car with an original 9790071 cast block, would receive a replacement block with the same number.
With that being said, according to my Pete McCarthy “bible”, the 9790071 block was a 1968/1969 two bolt main block casting number, so my initial thoughts were that the block being renumbered meant that it was an SR block intended for 1968/1969 application;
Again according to the “bible”, XH was a 1968 & 1969 full sized/G.P. 400/4bbl-350hp motor.
I think that it might be prudent to take pause and question weather the Pontiac foundry swapped over to the 1970 castings by March 1969 - the block being drilled and tapped for four bolt mains might seem to suggest this.
OR(!)
maybe the early motor mount bosses would suggest this was cast prior to the 1970 change over.
I am thinking now that this block was originally created as a 9792506 casting, but supply demanded that it be renumbered and used as a non-RA engine…
Does the block code ect. look legit?
Does the block have the G.P.’s partial vin on it?
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1970 Formula 400
Carousel Red paint on Black standard interior
A no-engine, no-transmission, no-wheel option car.
Quite likely one of few '70 Muncie three speed Formula 400's left.
1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing)
2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs)
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