Generation IV External Engine - Need some info on 6.0?

I just bought a 6.0 lq4 and i have some stock 5.3 heads layin around. Would the 6.0 run like crap with these heads. Im just tryin to get my ta runnin and im on a tight budget. Thanx

It would raise your compression and it would probably run a little better.

It would raise your compression ratio, but it would flow worse due to the smaller intake/exhaust valves.