[DeTomaso] 4-bolt Mains

[B. Seib]

During the Ford Pantera program, 1971-74, engines for Panteras were lifted
straight from the Mustang/Cougar engine supply line. The 1971 351C 4V had 2
bolt mains and closed chamber hi comp heads with a small square bore
Motorcraft 4300A carb. In 1972 Ford needed to lower compression to deal with
low octane unleaded gas. They retarded the cam timing, added a large 700 cfm
4300D spread bore carb from the Boss 351 and raised the rpm at which the
torque peak occurred. As a margin of safety, they used the Boss 4 bolt main
block too. This was an attempt to minimize the HP losses by raising the
stakes. In the end, most experts said the 4 bolts were nice, but unnecessary
in virtually all conditions except the most extreme racing efforts.

The Panteras destined for North America all had these carbs and engines in
order to be EPA certified for sale here. Sadly, despite Ford's efforts, they
were not as perky as the 1971 models, but not as neutered as the Chevys in
1972-74.

The small number of Euro cars sold in 1971-74 probably had engines picked
from the same Ford supply, but could have had modifications made by
DeTomaso...

What happened once Ford left and DeTomaso had his own way is someone else's
guess.

Barry




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Rich hoppe1 at cox.net
Sun Dec 29 15:56:57 MST 2013


I was a gearhead in the 60’s.
My opinion is Ford added 4 bolt mains to clevelands to stop the chevy guys
from saying they had a 4 bolt engine and the clevelands originally were not.
The 350 chevy’s needed 4 bolts to keep them together the Ford’s 351C did
not.