Engine Options?
First thing you have to do is actually Identify what you have so we are not doing this blind
Count the valve cover bolts.
5,7 or 8
Chances are it is has 8 which would make it either a 351M or a 400.
replacing whatever it is with a 400.... IMO, would be the best choice as it would be a direct swap.
There are numerous article about making the 400 into a powerhouse of that is what you want.
You can learn a l,ot more about these engines in the FTE engine forum relating to the engine you have.
Now.... go count the valve cover bolts and let us know how many.


