1965 426 wedge

[Kirk Morgan]

You can use the 440 block with a approved 426 piston as long as you are not .080 or more on the 426 bore and the block has the same deck height as specified for the 426 block.

[Coleydog]

Just looked at both specs 426 has a 2.015 comp height .042 deck with a .020 gasket. 440 has 1.94 ch .027 deck and a .021 gasket. No 440 piston has that ch except the 6 pac but it has valve pockets, a no no. So it’d have to be a .070 over 426 piston with the right numbers on top. What a can of worms.

[Paul Precht]

Originally Posted by Coleydog

Just looked at both specs 426 has a 2.015 comp height .042 deck with a .020 gasket. 440 has 1.94 ch .027 deck and a .021 gasket. No 440 piston has that ch except the 6 pac but it has valve pockets, a no no. So it’d have to be a .070 over 426 piston with the right numbers on top. What a can of worms.

The 413 industrial or motorhome blocks are the way to go and they are everywhere for a very reasonable price then get the correct approved 426 piston. There are 440 motorhome blocks around that have very little wear and if you get one finished to within 1-2 tenths taper and roundness with the desired hone finish at 4.325" the .005" over standard ring set will make it by a hair, you'll still need to use the approved 426 piston, they'll make it whatever size you want.

[Coleydog]

Back in the mid 70s my Max had a bad cylinder so I found an industrial block out of a 60 ton crane, it was a very strong block.

[Adger Smith]

MH or Industrial blocks have a water hole for spark plug cooling passages that are in the MH or industrial heads. They are easy to spot.
If you find a block try to get one that has the Dash end number(-1) closer to one or zero.
The higher the dash number the more mold/casting modifications. Closer to zero or 1 is usually a block that has been cast matching the original prints. A -1 could be a lot better core than a block with a -15 on it.
Sonic testing is important

[GTX JOHN]

I thought they only used the block castings ten
times 10 times before retiring them but that was a longtime
ago.

[Steve Stasko]

Originally Posted by GTX JOHN

I thought they only used the block castings ten
times 10 times before retiring them but that was a longtime
ago.

I've never seen a big block with a higher number than 10. The only one I ever had trouble with was a '65 -1 casting 440 out of an Imperial. It was stress cracked all through the lifter valley.