new guy with some questions

[fakesnake]

Hi guys,

I'm new to the old GMC scene(I've got a Ford and a Dodge) and I've got a few questions.

I just purchased a 71 GMC 5500 flatbed for my business. It has the 478 V6 with a 5 speed in it but has some nasty knocking going on in the engine. I have a line on another engine and was considering doing the swap, or else rebuilding the one I have. I like the idea of having the original size engine in the truck but I'm also not completely against putting in something different. It will be used on a daily basis and the bottom line is that it needs to be relaible.

My other option is going with a big block v8 which are a dime a dozen. If I go that route, is there any way to mate the v8 to the existing 5 speed or will I have to go with another tranny as well.

If I replace the V6 or have it rebuilt, what kind of life expectancy should it see. Also what is the availablility of parts to do the rebuild. Most of the driving is around town hauling a bobcat and equipment but it will also see highway duty from time to time, especially next winter. I've heard that these engines really don't like revving too much so I am considering swapping out the rear for something a little more highway friendly.

What are your thoughts on this? Keep in mind that the most important thing to me is reliability, not originality. It is a work truck and will never see a car show or anything like that.

thanks.