Would there be any problems with putting 1988 460 fuel injection on a 429 equiped with the 460 FI heads or a pair of heads form a 429 MD truck such as a F700? Will the ECU be able to tolerate the reduction in engine displacement?

 

You may or may not have to adjust the parameters within the EEC, I haven't tried that combination and generally 5-7% mismatch is okay with Ford stuff of that vintage and you're right at that limit.