I think aftermarket aluminum heads may be better. My reasoning is that adaption may be more expensive.

 

4V Iron heads are not as expensive as they once were, but adapters are. Good aftermarket aluminum heads flow better at low lifts, but are quite expensive by the time they are built up.

I thought the chinese were selling a cheaper aluminum head, but I haven't heard much about them.

 

Adapter plates. MPG Heads ask for scott. 303-762-8196. Or check into pricemotorsports.com . I use mpg parts and componets for some of my ford projects. Scott is a very smart dude when it comes to cleveland builds. He's also been a top finisher in enginemaster builds several times if your familiar with enginemasters competition. Good site to check into if wanting to see 400fords perform and win. their kinda extreme versions of what we would want to run but interesting combinations. I use scott because of his experience with high elevation tuning, he is in Denver Colo. I'm building a 4v 400 ford for 4wd. Also one thing not being mention's is your carb set up. For low end torque you need a annular style booster in carb. Down leg boosters and straight are OK but annular really help your lowend. It has more holes in booster to help vaporize your fuel quicker. If you check into holley truck avengers carbs this is standard on boosters on fronts. I like the annulars for low end and street running. If any more question on carbs for 4wds towing just drop a note. Quick fuel has a nice annular carb 750 that I've been looking at for my build. People will say this is to big but its back to tuning. I also run 1to 1 linkage setup on carbs for 4wd for smooth towing. Acts kinda like fuel injection in a way. I know I'm gonna get beat up on this but been running it for about 7 yrs and built many other setups and very happy customers. If serious on carb stuff drop me a note and I'll help in any way. I like to see our fords run strong especially 4wds.