1cm

[tubman]

Since this is said to be an original truck with an untouched engine, the combination of 1CM heads and a three-bolt carburetor has always bothered me. How about this scenario? The trucks had lower compression heads (8RT) than the cars (8BA). Maybe they ran out of 8RT heads and substituted 1CM units. The concurrent year Mercury's had a larger chamber because of the longer stroke. Everything turns out as it should, and the line keeps running.

Unfortunately, that would make it a 239. I think you going to have to measure it to satisfy all of the inquiring minds out there.

[Will D]

Can you see any casting marks on the block? Like "C1BA"...if so, good chance it has a 4" crank.

[Beater]

Originally Posted by tubman

Since this is said to be an original truck with an untouched engine, the combination of 1CM heads and a three-bolt carburetor has always bothered me. How about this scenario? The trucks had lower compression heads (8RT) than the cars (8BA). Maybe they ran out of 8RT heads and substituted 1CM units. The concurrent year Mercury's had a larger chamber because of the longer stroke. Everything turns out as it should, and the line keeps running.

Unfortunately, that would make it a 239. I think you going to have to measure it to satisfy all of the inquiring minds out there.

i live in the land of mercury trucks. you are the first one ive ever heard say that the trucks didnt come with the 3 bolt 97. i have about 400 trucks lined up, and there is exactly 1 truck in the yard, mercury or ford, that doesnt have the 3 bolt carb on it