rear spring help please

[jamon8]

I have a 69 1/2 ton 2wd

the front end is from an 84 deisel with a 6.2

I have not set the front end down but I know for sure that the 350 that is in my truck is much lighter than the 6.2 that the springs in my front suspention were designed for

I really dont mind the truck sitting a little high in the front end but I have to do something with the rear end before I put the bed back on the truck.

will the 3/4 ton HD springs make my truck sit a bit higher in the rear and if not what do I have to do to make the truck sit level

thank you