351W deck height question

[Pete Whitstone]

Hi all, trying to make a parts list for a new 351w build. It will be a 4" stroker crank, cylinders bored .030 over, for a final displacement of 408ci.

In order to figure out what rod length and piston height would work, I needed the deck height of the 351w. Not knowing a lot about the motor off the top of my head, I was surprised to find that internet searches showed the deck height was "9.480 to 9.503 inches". A span of 23 thousandths, which may not sound like a lot but is an enormous difference when calculating compression ratio.

I'm confused by the spec "9.480 to 9.503 inches". Were there two different versions of the engine, with 2 different deck heights? Surely that 23 thou does not represent a production tolerance... I don't see how you would ever get an intake manifold to line up and seal properly with that kind of variance.

What does that spec actually mean?

Thanks!

[Lima Delta]

Hi Pete,

Check the block casing number.

Sometime after 1970, 351w blocks started being cast with the taller deck.

Edit to say: it was an either/or deck height, not a variable.

[Pete Whitstone]

Hi Pete,

Check the block casing number.

Sometime after 1970, 351w blocks started being cast with the taller deck.

Edit to say: it was an either/or deck height, not a variable.

Thanks! It almost had to be 2 separate specs. The block I am concerned with is from a 95, so I'll have to see what numbers are on it and find a chart similar to that one, but that goes up through all the years.

[Lima Delta]

Thanks! It almost had to be 2 separate specs. The block I am concerned with is from a 95, so I'll have to see what numbers are on it and find a chart similar to that one, but that goes up through all the years.

I'm pretty sure that after the change to the taller deck was made, that dimension stayed the same for the rest of the production history.