i recently blew the motor in my 85 truck. got into some really deep water and sucked some up. few days later it pitches a rod through the block. before the motor blew it had a wierd power loss like it was hard to keep up with traffic, i assumed it was just whatever the water did so i ignored it. here is the issue... the donor truck i got for the motor ran great it had a bit of a skip but a tune up fixed that. i pulled the motor and stuck it in my truck and it runs a lot better there is still something wrong like something holding it back and i cant figure out why its so slow. it did the same with both engines and the new motor drove great in the other truck.... i am so frustrated with trying to get my truck to move with traffic.it will only do about 40 in third rapped out and doesnt have the power to carry 4th

 

Are you sure the timing is set right? Did you flush the tranny/t-case/diffs after the water fording? repack the wheel bearings? Is it carb or efi? Any codes? Auto tranny or Manual?

 

its carb, manual and i didnt flush anything yet... the diffs were low and starting to make noise so im going to fill everything with new fluid and see what happens. the rear diff used to spray out the vent on long trips and i never really payed attention to it until now. the new motor has about 125 to130 pounds of compression and a good carb and good spark. just couldnt see a little water slowing it down that much.

 

Okay, well from now on, if you suck water into the engine, as soon as possible, the sooner the better, pull ALL the plugs, and crank the engine over a bit, some water should shoot out. Dry the intake as best you can, and you should be okay.
Did you reuse the old air filter? Its possible it could be dirty. Can you describe the "power loss" anymore? like...vibration, a weird humming noise, etc., kind of thing? How similar to the first motor does the implanted one lose power?

 

it does make alot of humming noises and vibrations. exact same power loss the new one just has a little more throttle response... just overall a better motor

 

well im pretty sure what is causing my power loss, my rearend decided to lock up on me today... there was a pretty bad snow storm today and i had just put new fluid in my front and rear diffs and i had it in four wheel and i was on my way down a pretty big hill and the rear end started grinding really bad and locked up... any advice on things to watch for or take into consideration on changing a rear end or finding codes for gear ratios? thanks for all the help so far