[summitflier]

I'm sure you'll get several opinions on this.

As for the TH400. No problem, many of these trucks came with them. I ran a TH400 in mine until a couple of weeks ago. They're bulletproof for hi performance applications, not so great on gas mileage.

It would probably be easier to switch to a carb setup. But what's the fun in that? The Throttle body will give better response and gas mileage than a carb.
Some throttle bodys set up pretty high. (I don't know which setup you have) and require a raised cowl type hood for clearance.

Simply going to an electric fuel pump doesn't always work either. Make sure you get one that specifically has enough pressure to support fuel injection.