I have a 300 I6 guessing that it is a 1985. Not very positive the motor mounts; I purchased will not line up. The Bronco is 1985. How do I find out the year of the block by looking at the stamp on the block? I'm thinking of 're-building it next year . It's basically a weekend driver. I have heard of pulling around 300+ hp out of one and I think it would be pretty cool. I have looked at alot of threads but I need to know how to go about doing it. How to choose the right pistons, mild cam, what to do about the head, rods , etc. There is no-one around here that will do it so I'm gonna attempt to do it myself😯 I have also looked at crate motors also. Idk Any info will be greatly appreciated

 

The BIG problem with the 300 is the cylinder head and you will never get even close to 300hp without a much bigger head or with forced induction and a heavily ported stock head.
The block casting number will tell you what vintage casting you have, it won't tell you the exact year the engine was built but that's not really important anyway. Casting numbers can be decoded by following the link at the top of this forum.