Thread:

How to tell the difference between a tall deck and a short deck 454?

Running on Empty, The actual measurement is from the flat of the deck to the center of the main bearing bore ( center of the crankshaft ). A standard (short deck) block measures 9.800 inches, (just a little over
9 3/4 inches). A tall block measures 10.200 inches (just a little under
10 1/4 inches).

Originally Posted by ColeTR2

I have never heard of a tall deck 454 only a 427 If you want to build a big cubic inch BBC I'd just go get a new after market block. Once you do all the machine work on a old tail deck block you will find out it's only a few hundred more for a new block that's way better. And you can make it even bigger.

If you can swing the budget, a big +1 on an aftermarket block... I'll NEVER run an OEM block ever again. I just finished my first tall deck BBC, turned out pretty nice. I found a Bow Tie block used for a reasonable price, so they're around. With a tall deck aftermarket block, it's real easy to build a 632 with off the shelf parts.
We used spacers on the intake so a standard deck intake works fine. IMHO they look a little jankey but I can live with it.

mortec.com only has 90-91 IV being of any deck difference and my bolck is a 76