I just picked up a 429 which I intend to build to tow. It will be going in a 78 F250 4X4, 4 speed manual. The engine casting numbers are as follows;

Block D1VE A2B
Head D2VE A2A
Intake D3VE 9425 A1B.

This will be a long time build and would appreciate any suggestions which would provide adequate power and long term reliability. The truck will tow a large 5th wheel approx 5000 miles a year. Other than that I will use it probably no more than 4000 miles around home. I figure I can save on not buying a new truck and put the extra cash into the 5th wheel and the build so go ahead and suggest anything that is relevent to towing issues. CR, aluminium heads vs cast etc. Thanks in advance

 

Gear ratios? Over drive? Max min towing speeds? Weight of 5 th wheel? tire size?

 

First thing I would do before anything else is get rid of those heads, they are the open chamber heads that are very prone to detonation (pinging) this is niether good for towing or longevity. On a low rpm torque engine the D3VE heads would be a much, much better choice.
That block is fine, but something to consider is a 429 will usually sell for more money than a 460, and the 460 with the longer stroke will make more torque down low were you really want it for towing, not that the 429 can't make good power because it definatly can, it's just a thought in find someone to give you enough money for hte 429 short block, that you can buy a 460 long block with the better heads already on it.

 

Find a 460 from 73-87. Like Monsterbaby said the heads are better the stroke is longer and pistions are cheaper.
Leadmic