ls engine swap

hi,
I would like to use ls 6.0 vortec for my restaured 77, with a th350 and stock transaxle.

somebody allready do this swap?

first, I thinking about a fuel flex and driven by wire trottle, but will I have enought space for oil pan, for hood, engine mount wil fit?
ls to th350 mount and tuning?
stock transaxle will be strong enought?

thanks for advice.

I have done this swap on my 1981 Buick Lesabre which is a B body car with a similar amount of room that you have. Using Flex fuel is fine as long as you have a spot for the fuel sensor whether it is on the fuel rail or the sending unit depending on the set up you use. Drive by wire is easy as long as you can make the pedal assembly fit where you need it. You will not have enough space for a stock truck oil pan unless it is highly modified. I used a Holley oil pan number 302-2 and I like the way it fits. I was able to clear the stock hood on my Buick with a stock Gen 3 truck intake without the cover. No doubt the car intake would give you more room but if you are using a truck for the 6.0L engine the car intake will complicate the water pump/belt routing situation. I used the stock clam shell mount on the frame with new Energy Suspension inserts with Holley 12643HKR motor mounts on my engine.
Putting the LS engine to a TH350 is easy. The Gen 3  6.0L engines I have used have a spacer on the crank to support the TH350 torque convertor snout. From what I can remember the flex plate will bolt right up to the TH350 torque convertor as well.
It is hard to say if the stock transmission and rear axle will be strong enough. If you drive easy it will likely take it. If your transmission has a million miles on it and your rear axle is a 7.5" open diff and you want to do burnouts all the time it probably won't.

http://77-79capriceimpala.forumotion.com/t717-my-new-project

This is the link for my build thread. It is kind of two builds in one. I started on one car and jumped to another.

What is the engine you are using coming out of?