The 327 would be a better choice for a turbo app. The bore/stroke on the 327 has a lot less side-loading, plus, the stroke is so short you can rev 'em pretty hard without tossing a rod. It's pretty hard to toss a rod out of a 350 also, but the 327 is just hard core. If you're gonna go all top-end balls out power with no real desire to street, do the 327. I had a high duration, low lift cam in my '65 327 and it was laying down a solid 350hp and taching out to 7,000 RPM all day.

If those 327 heads need valve seals and springs, you should just invest the $150 at Clearwater Cylinder Head for a trade-out on those heads for some fresh ones. Best case scenario they're 1.94/1.50 heads, so it's not like you need to worry about losing something valuable. It'll save you time and energy, plus, you'll have new, tight heads. While you've got 'em off, do the lifters, the head gaskets, and any other gaskets that engine needs. A FelPro gasket kit for an SBC costs about $40 at Discount.

Seriously though, if I were you, I'd take the 327 out of the car for the weekend, drop the heads off, clean and paint that engine bay, toss the $40 gasket kit in the engine, and degrease that block before tossing it back in. It'll look like a million bucks. As long as the rings are good, a new set of gaskets'll have that thing running like brand new.

With that 350, I hope you had those Vortec heads worked. Stock, contrary to popular belief, they flow kinda like shit for any high performance applications. They'll make one hell of a torque monster, but at high RPM/high lift, they kinda lose their flare. Sounds like they might be good for a forced induction setup though, especially with a milder cam for the turbo.

Blah blah blah, preach preach preach, if you need any help, let me know. I'm pretty handy on old 60's Chevy engines.