My current job on my 1975 450SL rejuvenation involves replacing the troublesome exhaust manifolds with the integral catalytic converters...

I have seen that the recommended fix is to replace them with pre-1975 "cat-less" manifolds. The problem however seems to me that the pre '75's do not have the provisions for the EGR fittings on the left manifold. Is the EGR system just ditched/plugged, or should I use a catless manifold from say a '79which has the provision for the EGR?

As I've finally got the injection system running pretty good, I am afraid of deleting the EGR for fear that I'll throw off the damn injection system...Can the cat manifolds be replaced without throwing off the D-jet system??

Also- The early manifolds that I have seen are single piece and do not have the expansion joints. I've read that these manifolds are prone to constant cracking due to the inability to expand/contract at the rate of the aluminum heads...should I be concerned about this, or is there another pre '75 catless manifold that actually HAS the expansion joints???

Thanks.

J.G.