I am currently running a 1978 F-800 dump with a 477cid mated to a 5-speed eaton trans. (about 4 mpg) I am looking at swapping in a 1984 210 horse cat 3208 mated to a spicer 5-speed.

How difficult will it be to do this?

Fuel mileage?

Can that 3208 have a turbo installed relatively easy?

What kind of power gains can I expect?

The cat is a reman and has no blow by. How long can I expect it to be useful?

Any positives or negatives of the 3208?

Is the spicer 5-speed a good transmission?

 

This may be the wrong area for this type of question. You don't say where you live, but find a bigger city near you. Contact the local Cat dealer + ask him these questions. If he doesn't know, go to a bigger city + ask the same questions.
The 3208 is a very heavy engine. It will get 3 - 4 mpg, naturally aspirated.
Turbo is a good choice. Twin turbos even better. I'd contact Performance Diesel Injection, or some like, performance diesel people.
The 3208 is an absolute beast. A foundation puller, if you will. The trick is finding the right shop that will set you up the right way. Shop around for Cat dealers in logging country. They will know what you have, + what you think you want to have.
Two Co's that come to mind. Fabick Cat in St.Louis. Any northern Pa, or WVA Cat dealers, Louisville Whayne Cat. There are many logging operations around KY, S.IN. + S.IL.

 

The 3208 Is a solid engine indestructible i myself am looking for A Ford L8000 Twinscrew w/3208. I used to work in a diesel shop but have never heard of anyone swapping a diesel in place of a gas. The 3208 was used in wide varity White Farm Equip used them in their 4wd tractors (4-150,4-175,4-180) and 2wd 2-180, New Holland used them in many of their combines. Oliver used the earlier verion the 3150 in the 2255 tractor. Many truck builders used them in their trucks from Ford to GM to Diamond T yes I just seen a `74 Diamond T today w/3208 I thought Diamond went out in the 60s. Also power units and several other apps. I dont know of any problems with the 3208 but personally i wonder how they get by with such a small oil pan my White holds 6 or 7 quarts but ive never had any trouble the ony bad 3208 ive ever seen was used and badly treated it smoked so much it filled the shop but had so much oil pres it disconnected the hookup to our diagnostic gauge out. We just rebuilt it and never had a prob. Ive never installed a turbo on one but a cat shop can certainly do it if u want to pay for it, I have heard power of 230 on naturally asp and bet they could be higher, but with a turbo ive seen 290 and 310 wrote on shop tech sheets. there is plenty of room for a turbo but of course all parts should be specificaly made for that app. As for length of use the highest mileage ive seen (keep in mind speedos are commonly swapped out in heavy duty trucks) was 670000 Id bet it was much higher.