I finally got this 400 tore completely down and I'm seeing some pretty substantial wear and some grooves in the cylinder walls. So now I'm looking to get this bored. Just curious what y'all think about how much. 20? 30 over? What will I gain what will i lose?

 

The less you bore it now the more "meat" you'll have in it if it ever needs to be bored again. Boring 0.030 or 0.040 won't provide a measurable increase in horsepower or torque. My 2 cents worth!!

 

Bore it as little as possible. The less you bore, the stronger the cylinders will be.
Like Canus said, you won't see any appreciable HP increase just by boring. Boring .030" will give you about 6 cu in increase in displacement.

 

Right on! That was basically my thoughts also, but ive never done a rebuild of this magnitude so I'm just looking for some outside perspective

 

As stated, you'll probably never notice it since you a changing a small percentage of one power factor.

Coming from the Chevy side, its pretty cheap and easy to get pistons .030 over, so I'm guessing Ford is about the same. .030 is a pretty standard over bore.

 

Yea summit seams to have a descent set for about a buck fifty

 

A machinest will tell you how much needs to be removed.

 

Yea I'm trying to get off work in time to pay my machinist a visit