Personally, I'd go with the LT1 right now. It at least bolts in much easier, wiring it is the only pain. The LS1 shares jack squat with the GenI/II blocks - I suppose it's an SBC, but only because it's not the 496 Vortec. There is the advantage - if you wanna pay out the nose for the special block - of being able to punch it out to a 427! Imagine that...a 427 that weighs less and fits in a smaller space than the old smallblocks...
But the Optisparks on the LT1 are total crap. Whatever you do, DON'T LET IT GET WET. I bet it's less of a problem in our trucks than it is in Camaros, though. But these things still suffer from ignition problems like mad.
And I honestly doubt accessory mounting is going to be that hard. Have you ever seen the space the LT1 fits into in a Camaro? If GM can cram all of that into the Camaro (half under the windshield to boot!) then it should be no problem getting it into one of our trucks at all.
Plus, if you want mad power from the LT1...buy the LT4 HOT kit from GM. Cam, lifters, heads, rockers, and an intake. Basically, most of the top end, heh. But you could be looking at well over 400hp with that setup, on pump gas.
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