Hello gentlemen I'm a newbe here I have a 91 W150 I'm rebuilding
Block is junk will I be able to use a block out of a early 80's truck
And change intake . Or do I have to get a 88 to 91 block .Can
Anybody lead me in right direction thanks

 

Might consider upgrading to a magnum.

http://www.magnumswap.com/

http://www.magnumswap.com/using-la-parts-on-a-magnum/

 

I would upgrade also.

 

I had an 89 W250 awhile back, and it had the throttlebody injection intake on it. The only difference between the older blocks and the 88-91 that I can think of was the newer blocks had roller lifters. I ended up getting a block out of a '79 Ram for my '85 but I wanted to stay with the carburator setup for price and simplicity. As far as I know you should be fine getting an older block and re-using your intake. However I agree with the guys above that said to just upgrade to a magnum.