Basically comes down to 2-3 categories:
tri-y for ground clearance issues or the d.i.y sucker at home performing all work on the car at home.
1 3/4 4 into 1's for those willing to put up with clearance issues & heat all for the better sound & top end...mild cam & head 5.7/6.0
1 7/8 for those that just want crazier sound & top end power,clearance/heat issues even though more suited to 6.2 or strokers,f/induction.
Thanks but while it may be good info for readers, this has really moved away from what I was asking, I understand the differences between the choices. I have actually already had Tri-Y Pacemakers before I had 1 5/8 4 > 1 shorties. I personally wouldnt buy Tri-Y again over the CSV shorties (which were the pick of the bunch). I also have no interest in 1 7/8 headers. I am only looking at whether I move from my shorties to 1 3/4 4 >1 for my H/C LS1. Its mainly to free up some ponies, even if only a few but not pushed all the way to the top of the range like the 1 7/8 tend to do on a 5.7 (US guys love this option though).
So, the exhaust port question came into it, a basic point that seems hard to find an answer to surprisingly. However, clearance is an issue. Some say there are clearance issues with long 4>1, others say its brand dependent. This is what I was looking to try and work out. If its too much I just keep what I have, I wont swap to the bigger exhaust. Its been useful, I am now looking to check out the Hurricane headers which I forgot all about.
Cheers