[TonyMadrid]

I don't know the history of the block or whether you have had it miked. If not, my advice would be to take it to a machinist and have him bore dial gauge the cylinders to make sure it wasn't already 30'd over. Also have him mic the crank and rod journals to make sure they weren't already turned .010 or .020 under.

If it still has a stock bore and stock journals then have him flux the block for any cracks. If it's okay, then you're good to go with a 30 overbore and turn the journals .010 under.

One other thing you have to be aware of with 351W blocks is that the earlier blocks (I believe from 1969 to 1972) have a shorter deck height. This must be considered when choosing a cam to insure that you have enough valve to piston clearance. If it's one of the older blocks and you chosse a stout cam you may have to cut valve reliefs in the pistons.

If you look at the casting number of the block (on the side just above where the starter would mount) you can determine the year of the block. If it starts with a "C" it is a block from the 60's; if it starts with a "D" it's a block from the 70's the next digit will tell you what year within the decade it is, e.g., a C9 would be a 1969 block, a D4 would be a 1974 block.

Hope some of this helps.

Tony