I am replacing the engine in my sons 1970 F100. I know that the engine is a 78 351w, do I need to know what it came out of before ordering the longblock? The dipstick is in the front right side of the block. I will be replacing the intake and carb also so I'm not too concerned about the intake matching up.

 

If you want a new longblock that's close to what you have, just the info that it's a '78 should be sufficient. But you might want to consider getting an earlier one so you get the better heads, unless the rebuilders are particular about getting a core back that's exactly the same as what you bought. Might be able to upgrade for a little extra moola. '78 was not a great year in terms of heads. Low compression, smaller valves, low power...'70 through '77 were much better.

 

1978 did not have a 351w stock. they only had 351m

 

Thanks Tigerdan, I am not returning the old long block. I will take your advice about an earlier year.

 

you better make sure you infact have a 351w.

 

I'm sure it's a 351w my wrench tracked it down and the guy I bought it from confirmed when I got the truck he had changed the engine.

 

instead of taking someones word , i would count the valve cover bolts. the number of bolts is unique to all the series of engines. see if you have 8 bolts.