[purple gas]

What is your budget and what is your goal are the first 2 questions to answer.
Do you want to go racing & doing lots of smoky burnouts?
Do you want bragging rights? " It's got a Corvette engine"!
Do you want decent performance and no trouble dependable drivability?
For work I used to drive a 2004 -2500 chevy, van . Got it brand new and put 500,000 Km on it. Didn't handle very good but off the line and passing performance was impressive to say the least. Freaking amazing actually even with 3,000 lbs of meat in the back running AC and a Cooling unit. I've wanted one of those in my 67 ever since.
I talked to a few guys this summer running bone stock 5.3's. They say plenty of power, lots of torque. Really fun to drive.
I just bought an '02 Silverado for a daily/ winter driver. It's got a 4.8. with 160,000 Km on it. Sure doesn't have to jam of a 6 litre but I'm not pulling a trailer and I'm too old & boring to do burnouts. If that drivetrain was in my 67 it would do what I need as good or better that the HO 305 with headers & Edelbrock goodies bolted on to it.
My mechanic / car flipper buddy says 4.8 is undesirable because they're no good for towing. Might be true but it's fine for groceries and the odd trip to the lumber yard.
quick google search on 02 Silverado Specs.
4.8 - 270 HP, 285 Ft. lbs
5.3 - 285 HP, 325 Ft. lbs
6.0 - 300 Hp, 360 Ft. lbs.
There's other options out there of course. Me, I'm looking for a running donor for my truck, either a driver or a write-off. If I score a 6.0 that'd be cool, if it's something a little smaller that would be fine.
It's suddenly winter here and wednsday I nearly got smacked at an icy intersection. If I had I'd have bought back my truck from insurance and I'm sure the 4.8 would serve me nicely in my 67. I'm not looking for bragging rights or smoky burnouts.