what is the reason for the cylinders being longer(6 1/4) in a D9TE block and 6in in a D1VE block??Which is the HD block?Which one to build up??Thanks

 

I assume you are talking about the bore height from the bottom of the bore to the top of the block. It may be because of where Ford increased the deck height of the block to decrease the compression ratio from the early 460's on to the newer ones. I don't know. According to a book I have, the deck height was increased from 10.300 inches to 10.322 inches. Between this and increasing the cc's in the heads they dropped the compression from 10.5:1 to 8.5:1

Superdave

94 Ford Aerostar XL 3.0L
82 Ford F250 4x4 XLT,400 CID,C-6 A/T,8700lb GVWR. Black & Silver

 

Longer cylinder bores provide more support for the piston. This keeps the piston more squarely in the cylinder at the bottom of the stroke. This should reduce wear during high power conditions.

Ludis