There's a $100 difference in the 3/4" and 7/8" long tubes from TSP, and if it's OK to run the 3/4" headers with my mods then I'd much rather prefer that route.

Mods include an SLP lid, long tubes, an O/R Y, LM1 cat-back, a 3,800 stall, and 4.10 gears.

 

You could run the 1 3/4" just fine. Plenty of people on here do. But you'll likely leave a few ponies on the table. Also, if you're planning on any kind of heads or cam swap later, do yourself a favor and get the 1 7/8". Remember our motors love to breath big, in and out.

 

Yeah it wouldnt be anything you would even notice. You would gain alittle on a h /c car though.

 

With H/C, small gains will be there but will be minimal.

1 7/8 isn't really NEEDED until you go big cubes or FI.