400 ci or 350 ci

[Adub]

The truck I just bought says it came originally with a 400. Owner wasn't sure if the engine was original. Is there any way for me to tell?

AW

 

[sled_dog]

on the back of the motor where the trans bolts to there will be a casting number.
http://www.mortec.com/location.htm

then just search here http://www.mortec.com/castnum.htm and it will let you know whats in there

 

[boz42]

if it is a 400 & has the correct balancer on it u can tell that way. a 350 balancer is smoth all the way around. a 400 balancer has a recessed spot that runs almost half way around it.