will a dc 4-1 header for an si hurt performance in my b18b?? i was really stupid thats why! i bought a header for a si and installed it on my ls.. i felt a little power.. butt dyno!! i thought all dc headers have all the same sizes.... is it really that bad if i keep em???

 

No problem at all. As long as it fit good.

 

soo it doesnt matter if the tube sizes are diff?? the ls ones are bigger than the si ones.!! jus to clarify things... thanX

 

tube sizes? they are all the same... just made to fit each car differently...

 

the primaries are not thesame! the si header is smaller!! thats what i thought too, but i guess were wrong....