Deck clearance

[Doba76]

Anyone here know what the deck clearance on a 400 is? Mine is running absolutely perfect right now, just planning ahead for some future mods and don't feel like tearing a head off just to check. I've heard 3 numbers, .125, .121 and .080 below the deck.

 

[XCELLR8]

The 77 400 I took apart to put a cam in, measured .109" down from the deck. A 76 400 I tore apart for rebuild was .112" down IIRC.

 

[5.7 hemi]

Zero deck that 400 and stroke it!!

 

[gkent]

"perfect" and "efficient" are two different things. Ideally you'd want the compression to be only low enough so as not to detonate on pump gas. So with iron heads you can figure around 9.5:1. Now crunch the numbers and figure what that deck height "should" be.

 

[moper]

They are way down in the bore. All you really need to know is they actual measured static compression is about 7.8:1 with factory casting heads.

 

[XCELLR8]

Keith Black makes a pistion that is .100 taller for the 400 block. KB240 is the pistion number and they come in over sizes too.