I'm willing to bet 40 PSI Is EXTREMELY far out of the effiecency range of that turbo and will yeild VERY high egt's and not the HP you are looking for. However it does seem like if a set of lighter/stronger rods and pistions could be made you would be in good shape. If you are looking into new pistions there no reason why you shouldn't shave a point or two off that compression ratio tho. That will allow you to handle the boost you want and keep the head gaskets in tact. I don't know to much about multifulers but I don't think one or 2 points of compression will effect the multi fuel status. I know i have put vegi oil in an older ford diesel, don't they run around 16 to1?
If I was willing to try and figure this out I would but I have been thinking there are lots of small tweaks that you could do these motors to really make them alot better. I don't even have a deuce but if I get one I'll be looking for a spare motor to mess with.
A few things I have been thinking about...
1. Drop compression slightly... I'm not sure what a heavier gasket + alil polishing would yeild... need to take the time to do the math here. Unless someone smart wants to jump in.
2. Port/polish up the exhuast manifolds and all piping turbo related. Also ceramic coat them or thermal wrap them. This will help in turbo spool up and make your horsepower useable sooner.
3. Bigger intake, There was a thread about the big K&N filter.. This could never hurt if these vehicles are being run around farms and town, not the deserts and extreme conditions.
4. Intercooler, to not effect spool up to much (mount as close as possible to turbo) a water to air cooler could be made. I have no experience with W to A coolers but I know they run them on pulling trucks so they should be plenty (if built right) to cool the charger air
5. water injection.. only problem is this takes you back to raising cylinder/compression forces...thats one of the things we were trying to bring down.
6. Anyway to bypass coolant flow to the intake? I'm not familar enough with the set up so I'll ask. I don't see any problems with is as most of the US probly doesn't need this.. (guys up north which seems to be alot of you, how hard do these trucks start in the winter?)
I had a few others but these are just off the top of my head. Anyone feel free to comment on these. My theory is that on a motor not making huge power a combo of many small things will actually yield a noticeable change and make the truck more fun to drive.