Stamped across the top of the block in my Shelby are the words M-E-X-I-C-O. My car has a Mexican block in it. What is a Mexican 302 block?
Ford of Mexico manufactured 302 blocks for cars made in Mexico. And these blocks were stamped with MEXICO on the top. No US production line Ford cars came from the factory with a Mexican block engine installed. The blocks were available in the aftermarket in the US. Apparently, this block has more nickel in the casting. This alloy content of the iron block makes it a stronger block.
So how would a Mexican block end up in a 1968 Shelby Mustang?
Well, rumor has it that in 1968 Shelby American offered a very special small block engine in their GT 350 cars. 1967 was the last year for the Ford HiPo engine. The stock 1968 Ford 302 was a 230 HP rated 4 barrel. According to this internet rumor, Shelby American one upped Ford by installing a special prepped 302 based on the Mexican block. Click here to read a version of that story in the middle of this Wikipedia page.
Or the only other way I could have that block is the first owner had an engine problem and ended up replacing the block with this one. I didn’t know about this block until long after I had the car so I never asked the first owner.
I did talk with the SAAC 1968 Registrar about it. He told me that internet rumor is exactly that and Shelby American never installed a new engine in the 1968 GT 350’s. Mexican block or not.
I’d take SAAC’s response as truth since they are the experts on early Shelby American cars. But I still have a Mexican block in my car. So had it been broken it was not the original engine anyway based on SAAC.