I am thinking of going with 6.2 prechambers in my 6.5 heads on the 98 I am putting together. From what I have read with the smaller 6.2 prechambers the fuel speed is higher when it leaves the chamber and results in a substantial gain in mileage. I am not going to be towing heavy loads with the truck mostly just driving. So any increase in mpg is what I am going after. Now I don't want the truck to be a complete slug. Some things I read says that in fact it improves performance. The only thing I do no for sure is that my 6.2 does a lot better on fuel with lower gears than my 6.5. What I was wanting to know is if any one has done this and what the results where?

 

i have also heard that the 6.2 precups help mileage but i kinda doubt they will add performance since there are guys boreing out there precups and reporting better power. but try it out see what happens.

 

Well that is the one big difference between 6.2 and 6.5. My 6.2 gets in the mid 20's and my 6.5 has never broke into the 20's. I read on some other places that the smaller chambers bring out more of the bottom end of the engine and the larger ones are top end. Which would make perfect sens because my 6.2 also lugs at the low end better than my 6.5 but has nothing off the bottom. Banks swears the turbo on a 6.2 will out perform a 6.5. I guess I would know the answer to that if I had not procrastinated and put the turbo I have on my 6.2. I am going to use the 6.2 percups but have not decided whether to put them in my 98 heads or use the whole 6.2 head. The 6.2 ran bigger valves in the head but I don't know if it would be enough to change anything. I would just like to find someone who has done this and what there results where but I guess thats one of the problems when working on a 6.5 nobody knows anything about them.

 

good flowing heads never hurt engine perfromance so i would stick them in the 6.2 heads.

 

Yea I am kind of debating that. I have a set of 6.2 heads that I have ported polished, pined the cracks in and have new valves for. The only problem is finding some one to put the seats in the heads without welding the cracks. I think for know I am going to put them in the 6.5 heads I have and save the 6.2 heads for the next block. I am planing on building another 6.5 or 6.2 to replace the 506 block in the truck now. All that might change though because I am going to pick up another set of 6.2 and a set of 6.5 heads from a friend and it just depends on the shape of them.

 

i got a 6.2 that i am rebuilding wat do u guys know about puttin 6.5 heads an exhaust and intake off of the military 6.5 that has the turbo on top will it fit on a 6.2 ive heard it will and if so im sure it makes a nice improvement on performance and sugestions would help alot

 

It will fit as far as improvements I don't know if you will gain much. The 6.2 has bigger valves than the 6.5. It's not much but a little bigger. And I am not sold on the fact that bigger prechambers means more power. A turbo 6.2 will perform as good as a 6.5 and get's better fuel mileage.

 

x2 whichever has bigger valves use that pending inspection of course

 

i dont know anything about the military turbo set up, is it the same as the vans?
if you dont have a/c you can just use side mount 6.5 set up.

 

Yea it's the same as the van's. A side turbo will clear the a/c. The only problem with putting a center turbo on a truck is it wont clear the fire wall.