Mine was like this when I replaced it this time last year, the flanges of the two header crossover pipes met the collector flange at a slight V angle. �I was able to use some Permatex Copper Spray Gasket (recommended by one of the Advance Auto guys) and load up the mating surfaces adequately for a good seal. �Still holding. �

After I was done, someone wisely suggested that I should have belt-sanded the uneven mating surfaces to try leveling them and had I thought of this before testing successfully I'd have done so. �Try belt-sanding first and use the copper stuff as insurance.

Also, the other reply about loosening everything up and tightening it all incrementally is a good idea in any case. �That way, you do not preload any single piece in the wrong position.�
Stephen

--- On Wed, 8/29/12, Gregory Smith <gfs@GREGORYFSMITH.COM> wrote:

From: Gregory Smith <gfs@GREGORYFSMITH.COM>
Subject: '88 Exhaust help
To: vanagon@GERRY.VANAGON.COM
Date: Wednesday, August 29, 2012, 11:52 AM

Hi gang,

I
 recently had to replace my header pipes and 2-1 manifold.� I'll spare
the horror stories of getting the old rusty parts off.� Except to
mention the one broken stud that took more than 4 hours to coax out
using heat, PB Blaster, vice grips and patience.� And a sawzall is sure
handy.

Anyway, the new pipes and gaskets are great, but I can't seem to get the
dual-pipes-to-manifold joint to seal, where I have a noticeable leak.� 

I think I need to loosen everything and start tightening at this
particular joint, but any suggestions are appreciated.

Gregory Smith
'88 Vanagon GL

Smith Design Studio
Small Building Company
Olympia, WA
360-239-0429
gregoryfsmith.com