I'm posting for one of my friends. He wants to know if a header for a B16A will work in his B18C (GSR)?

 

yes, all b-series headers fit each other.

 

Not entirely, the bolt pattern will match up, but there may be a problem with oil pan clearance. The b16 is 'shorter' in terms of height from the bottom of the oil pan to the header than the b18c. So some people have run into problems trying to bolt a b16 header onto the taller b18.

However, a b18 header will always clear a b16 oil pan, there will be a large gap between the oil pan and header. I have seen people with b16s running b18 headers, and they have lots of room beneath the oil pan, but the header comes very very close to the ground.

 

Thanks I'll let him know.

 

It really depends on what headers you are using. 4 to 1 will not have the clearance but my 421 is ok.