Been told hot rodders like to do this swap.....
How hard is this to do? Like what is all involved??
and will this swap increase fuel economy?

 

The pistons on the 12 valve and the 24 valve have different combustion chambers. So, if you do the swap, you also have to swap the pistons. You will also need the 24 valve configuration exhaust manifold, and various minor parts. Then you need custom injectors and a set of spacers that will place the injector at the proper spray pattern for the revised combustion chamber. The cost is substiantial, and around $6,000 for parts alone.

I have done a number of conversions such as 24 valve head and pistons in a 12 valve with a P pump; and the conversion of 24 valve to a 12 valve head, pistons, exhaust manifold, timing gear housing, and P pump. Frankly, they are all a waste of time unless you have a particular speciality application in mind and a whole lot of money to burn.

The reliability of aftermarket VP44 injection pumps and electronics has improved in the last few years to the point that you can acheive power and economy gains on par with a 12 valve with simple plug and play boxes and a new injection pump (or two).

There is no good reason to ever drop a 24 valve head on, and 24 valve pistons in, a 12 valve. That is taking giant steps backward and into an area of lower reliability because of an inherent problem in the 24 valve where the head cracks between the exhaust valves when the power is turned up and a load thrown on it.

 

I am talking a 12 valve head on a 24 valve motor...you have it the other way around.
My brother has a 92 engine ...a good one...and he has a 99 24V truck. The mileage stinks with the 24v motor and he is thinking about putting the 12v head on the 24v motor to pick up sopme fuel mileage.
I told him he is better off switching the entire motor.
Them 24v motors stink as far as I am concerned. This is why I sold my 2001 Dually HO 6speed and purchased a 97 12v 5 spped truck .
I wanted the reliability and economy only the 12v can offer.

 

The same thing applies, you still need the 12 valve pistons with the swap. The injectors on the 12 valve head will work just great with the pressures of a VP. He will need a custom set of injection lines, and a means to handle the fuel return, but that is pretty simple. However, by the time he swaps the pistons, I really do not see what was gained.

One thing of which you need to be aware. Under the federal EPA statutes, you can really get sideways after the first of next year with an older motor or older non-OEM certified parts configuration in a newer truck. The penalties will be severe, right up there in the thousands of $$$.

If the 24 valve is in good shape, just do the tuning fuel box thing and buy a new VP44 and a decent transfer pump when the originals crap out. The cost will be way less.

 

Gotcha.
What is this "tuning fuel box thing" ????
My brother just coughed up the blood for a new VP44 (still feels the burn)
I guess you answered my question on the swapping deal. Not really worth it at all.
I guess if it(the head swapping) was simple and easy and beneficial,everybody would be doing it.