Thinking of going LSx

I'm set on buying a roller that has a big block in it right now with a Turbo 400. Would it cost/benifit me more to go with a 3.8 or a 4.1 or just go LS and add some boost?
thanks,

If it doesn't already have a turbo 6 in it, doing an LS motor would be cheaper and run a lot better. Sell the BBC, keep the th400, turbocharge an ls motor, and go buy some adult diapers.

What would be a good turbo to go with it..Whats the best way to go as far as tunning/ecu

This.

Nice..My buddy is selling his 87 Gn, Has 40k orig miles, a few mods for 14k. The guy selling the roller wants 8k. Would I get in 6k with the turbo ls1 swap?..roller in pic.

Without details on the BBC, I doubt anyone could be very accurate in making the "guesstimate" you are asking for...
Obtaining a market value on it would be a way to answer your ??
Turbo size?? Pretty much is answered once you decide on the LS combo............

turbo size is gonna depend on what motor you run, how high you are going to spin it, and how much power you want to make. I have a truck 6.0 sitting in my GN right now, I'm going to run the stock longblock, maybe change the cam and rod bolts, and that's it. It will get around an 80mm turbo, which is pretty small for 364ci, but it's a street car.

You could run an 88, 91, or 94mm on these motors pretty easily, just depends on what you want to do with it.

As far as 6k, it's probably going to end up costing more than that. Depends on how much of it you do yourself. I bought my 6.0 for $750, 4.8s and 5.3s can be found even cheaper. You could possibly do it all for less than 6k, but keep in mind your transmission, fuel system, mounting, and turbo hot side costs.

I bought EFI live from a member here, that's what I am going to tune mine with.

The big block isnt sold with the car..Its sold as a roller. So im pretty much asking whats more cost effcient/hp wise.. boosted ls1 or 3.8/4.1

"I'm set on buying a roller that has a big block in it right now"....I guess that's what mislead me.
As others have said... LS.

There's a nice looking GN with a 6.0 LS motor and a bunch of suspension upgrades in the Cars For Sale section. It looks like a real good value, and its all done. Just sayin.