If they are the cheap ones with a hump off ebay they are 1 5/8" x 2 1/2". If they are the real obx headers i think they might be 1 3/4" x 3", but not positive on that second one..

 

restricted boost reading are misleading as said before. You cant figure 10rwhp/lb boost if half of your boost is built by backing up and not flowing thru. Kinda like fuel pressure when your using nitrous, Make sure to set it flowing not backed up. lol

 

OBX have 1 5/8" primaries, 2 1/2" collectors, and 2 1/2" y-pipe.

 

so they are decent long tubes then, how much of a difference would it make on my set up by going to a 1 7/8 - 3" collector as oppose to my obx headers?

 

are yours the ones with the hump off ebay? if so, yes there would be a decent improvement up top with a bigger header on your setup..

 

i got them off a guy here locally for $150 bucks but yeah they have a hump on them.
what are some good headers the doug thorley tri y ? or the dyna maxx ? or what do you guys recommend?

 

American Racing Headers, 1 7/8" primaries, 3" collectors, 3" y-pipes to 3 1/2" outlet.

 

http://americanracingheader.reachloc..._id=5437795169

 

any one know the sizes of Pacesetters?

 

Pacesetters are 1 3/4" primaries and 3" collectors & Y.