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]

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]

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.