I need a good running small block for my 68. Would anyone know what years I can use? I am looking for 351, 302, 289 engines. Are there differences in what will work with the Mustang? I am using the stock C4 trans.

 

I'd look for an 85-up 302, set up for a roller cam. Get the mileage and performance of a roller cam without the higher cost of the retro-fit roller setups. Or a late model roller 351. Either way the roller setup would be prefered from a performance and reliability standpoint. It's getting harder and harder to run flat tappets with the oils these days. The later model blocks don't have provision for the mechanical clutch linkage though, so if you ever convert to a manual then you'll need a cable/hydraulic, or an adapter bracket for the older mech. linkage.

 

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Thanks for the help.