Fuel Economy . Ls1 vs 6.2 Diesel

Question; what would be cheaper to run . an Ls1 or 6.2 Chev Diesel! Hypothetically, both engines are being considered for the same application i.e. put into a mid 50's US based pickup. The intended use of the truck is as a everyday vehicle with the odd tow here and there. I have owned a 6.2 before (since sold) but never really took much notice of the fuel usage. Suffice to say, I was ok by it. The figure 6.3km's per litre of diesel rings a bell though. And if this is correct, then it was got from averaging a tow trip (tandem transporter trailer loaded one way only, with full sized sedan) from Palmerston North to Auckland return. That works out to be around 16/100 L/kms! I know RUC (in terms of running a diesel vehicle) currently costs me $0.04 a km. The 6.2 wasn't a grunter in the towing department but it held its own ok and was more than adequate for everyday running around. I have never owned, used or have any mates with a Ls motor, so don't know what they go like but would suspect they go well (like real well, lol!) but am interested in their economy. Even comments (along the same theme) re use of a 1UZ in the same application are welcomed also. Ta. Oh yeah . self imposed limitations, due to the intended use of this vehicle - there is no emotion involved whatsoever when it comes to the selection of a motor except that its got to make the right sound, perform adequately and be the cheapest bang for buck . so no suggestions about putting in 6BT's 4BD1T's 1HDTs etc. Probably all better suited, but none make the right sound, lol!

Never towed with an LS1 but had one with 6 speed manual in a 2000 commodore. Around town saw me getting 13.5L per 100km. And open road saw me at 9.5L per 100km. Im not light footed and dont worry about how much fuel I use. if that is a good indicator of the fuel usage vs driving habits.

towed a furniture trailer to christchirch from nelson think it worked out at 15l per 100km

woops that was with a ls1 in a vt commodore

My 6.0L in the VE Commodore get 16-17L around town, weight 1800kg

The non-turbo 6.2 are not great engines. hence why there are brandnew cylinder heads available for them. they tend to crack them due to bad heat dicipation around the exhaust ports.
LS1 would be my choice for several reasons.
Lighter being alloy.
6 bolt mains, so strong bottom end.
Newer technology (so to speak).
Aftermarket parts are plentiful if you decide to do a little work to it at some stage.
Are relatively economical being EFI.
Dont require RUC being a petrol.
Smaller in physical size.

I am currently looking at bringing a Chev pickup back later in the year for my father & will be fitting an LS1/4 stage auto (or TH350) to it. Also HOPEFULLY strapping a Duramax & Allison auto on the tray for another project I have.
This is only my opinion but I would'nt have even considered using a 6.2 diesel. horrible rattly old things.

Bang for buck would have to be the Toyota V8 though as they're incredibly cheap.

Gents, thanks for the insight provided on your Ls1's, petrol 8's have come a long way in terms efficiencysince the days of carbed 350's in the 80's aye! Guider1 agree, the 1UZ looks like a starter in the petrol stakes . I still like 6.2's though, lol! Thanks all.