I might swap a ZC into my 88 civic (I just have to convince my dad that its a better idea than getting a stock motor FOR THE SAME PRICE ) And I was wondering if I could use my old headers so that I won't have to get the exhaust welded together (I'm not sure where the exhaust would be cut on the new motor). Ideas?

 

You can use your old exhaust manifold, just make sure you port match as one of the exhaust ports is a smidgen off compared to the standard D-Series head.

 

Does anyone sell a custom downpipe that will bolt to the ZC header and my exhaust?

 

Yeah get a 92-95 Civic Si or EX downpipe or a 96-00
Civic EX downpipe, it must be a 2-1 downpipe then just order 2 Round crush gaskets for the Downpipe you get.

I have used a 94 Civic Si downpipe on my 88 HB with no prob.