Hoping i can get a mod to mark this resolved, not sure how to myself. Anyways, I should of just taken Redwidows advice from the start, but decided not to in interest of saving time.Turns out googling till my eyes bleed took even longer, but i finally found it and on eBay of all places...
Anyways summit racing had an auction for my same model number and had the dimensions listed (i wouldn't of trusted it if it wasn't summit, always had good luck with dealing with there website)
Collector Attachment Stock flange
Collector Diameter 2.000 in.
Flange Style Standard
Flange Thickness (in) 1/4 in.
Gaskets Included No
Header Finish Ceramic coated
Header Material Steel
Header Style 4-2-1 two-piece
Motor Mounts Included No
Primary Tube Diameter (in) 1 5/8 in.
Primary Tube Gauge 16-gauge
There is the info if anyone else has the DC sports header model #MHC4001 and needs the numbers.
On a side note, if you are ever searching for DC items, its much easier to Google the model # than anything else, i tried 420a dc header/ DC sports header/ dc header dimensions/ talon dc header, and about 100 other things. Model #'s are ones friend