glw165

just got this 79 f150 4x4 guy said was a 400, but how i know for sure without tearing down? has rattlin maIN bearings, and for correct crank i need to know which i have>?

dirtcrew51m

Identical motors only difference is the stroke.

Aaoxen

Hey, you should be able to tell by the vin. It is locate on the drivers side door jam. There is also a sticker that is on the driver side of the valve cover that should say 400 CID. However, the engine could have been swapped. This makes it hard to know because the 400 and 351 virtually look the same. One subtle difference that the harmonic balancer on the 400 is slightly thicker.

bales74f1

Did ya figure out what it is? Only way i know how to tell without tearin it apart would be takin a plug out and try to measure the stroke using a piece of wire