[special-K]

I would look at your ultimate end use and go from there. Chose what you feel would be best for your 500-1,000 mile trips.

I have an extremely s....l....o....w moving '67 SWB project I too am building with spare parts. It is a old school build because that's what it's all about for me. If I want an LS-powered SWB I'll buy one that came with one. All these swaps going on just to have different sheet metal when you have it all with turn-key factory reliability either from a used truck costing not much more than the swap or a roll off the lot new truck that is truly modern. Chevy/GMC SWBs are and always have been super cool, with a crowd that follows.

Ok, back to my project. It will be an era, meaning '65-'75, mild custom hot truck. Nothing on it you wouldn't have seen on a truck when it was a few years old... same as back in the day. I'd like it to have a rake and 10" steelies on the rear, except I want to hit the rod runs, shows, and do general travel all over the country. I'll be retired before too terribly long and this will be my cool travel machine. So, I'll want to be able to do four or five tire rotations and I think a level drop will be more comfortable when driving all day. Next is the 327/M22 combo and I love gears with grunt. Although I intend to travel off the interstates whenever possible, I don't own an oil well and you can't avoid running on the interstates at times. So 4.10s (my favorite/and gears was where it was at in the day) are out. And since I'm compromising there, might as well skip 3.73s and go to 3.42s. 3.07s are too tall for the 4spd and have no pull. While I'd love to sneak a Gear Vendor unit under there, I'm not sure I can make that happen. 3.42s, IMO, are on the line where you can roll along well in straight drive or go with O/D and have the grunt to stay in O/D. So here I have this super cool rock crusher I can't wait to throw the shifter on, but realize I could get serious coin from a '65 Pontiac A body owner who needs it and slap a T-5 or Richmond 5spd in. Looking at my ultimate end use it would make sense to go O/D. Not that I haven't been running my trucks (8-lug/4.10s) down the interstate traveling interstate at a steady 75-80 all day long for as long as I can remember. To be honest, I don't drive that fast anymore, even with O/D. But all those trucks were built that way from factory. Building from the ground up I have a chance to built to better suit the use

In all this, my intent is to show how it is important to consider the ultimate use. If you don't share the passion for for the better days these trucks came from and want to run it out 10 or more hours a day and don't own your own oil well, the LS would seem the better choice. I would go with a 4.8 to get the greatest advantage from modernizing... way better fuel economy. Big blocks like fuel and are from a time when fuel cost 10% of what it does today