i have a 1990 GS with a B20Z…
queation is…will B17A DC header fit my B20Z…i know ill prolly have to extend my O2 wire…how bout the length on the downpipe???
need to know asap…thx ppl 
Yes, all b-series headers will bolt up to all b-series heads.
Later,
BR
sorry BR…juss need to clarify…
i know it bolts up to the head…but does it match up to my existing cat or does the cat back piping need to be extended :run: or shortened…im putting it in today and i dont wanna remove the OE header and find out it doesnt match up :gay:
thx for the reply
The motor that you have installed isn’t the issue in terms of length - as BR stated, they all fit all B-series motors. Where length to the B-pipe becomes an issue is what year your car is. The B17A DC header will only line up length-wise on a 92-93 DA, so assuming you have a standard 90-91 cat/exhaust steup (length-wise), in your case I think you are going to be a little bit off.
ahhh okok…thx Ive… :werd:
now i gotta grab that RSR extension of Steve :getsome:
thx guys!!!
Ive is right. I missed the part where you said you are going to use the different header. I was under the impression that you were using the one off your old setup.
The header lengths and the catalytic converter lengths are different as well, so the easiest thing to do might be to take your car to an exhaust shop and have them extend your cat for you. Thats what I had to do when I built my engine.
Here is a pic of the difference in cat sizes…
Cut and paste this for original or if above doesnt work… http://www.imagestation.com/picture/sraid45/p6482a678ceea69d65a2109f3ee8c7b73/fcd21dee.jpg.orig.jpg
I dont have any pics of header length differences.
Here is what I ended up doing with my cat when I built my engine…
Cut and paste this for original or if above doesnt work… http://www.imagestation.com/picture/sraid117/pa792aaccab9909a3fe112d3822d5a7aa/f8a4e2b0.jpg.orig.jpg
That pic is of my b18c1 with a 94+ RSR header and catco high flow cat bolted up to my RSR exhaust. As you can see, the cat inlet has been extended by about a foot. I cant remember the exact lenght, but it was around there.
Later,
BR
peeeeeerrrfect!!! 
thx again :burnout: