pre cat exhaust manifold variations

[Iain G]

My 92 pre cat Griff near side exhaust manifold has cracked yet again and having been repaired twice already is now beyond recovery. However, I have managed to obtain a second hand re-manufactured one, it has arched tops to the manifold to head flange exhaust ports, whereas the original manifold has flat tops to the ports. Also having problems with manifold bolt alignment and it would seem I might have to open out the bolt holes in the manifold flanges. Anyone got an idea why there is a difference, does it matter?

[2 sheds]

The arched top was used to work with stage 4 heads, JP had all the flanges pre cut and used these for all Griff / Chimaera manifolds, it sounds like you have one of these systems, they will work and match your heads OK, they can be a bugger to fit, at worst you may need to enlarge 1 or 2 of the bolt holes.
Tim

[Iain G]

Thanks Tim, have had a go at fitting the manifold and now believe you are a master of under-statement and very polite about the job! Yes, I need to elongate at least 2 if not three holes. I'm also now a little concerned that the steel gaskets may not seal correctly as the raised sealing face on them doesn't match the shape of the manifold ports, what do you think?

[2 sheds]

As long as the gasket matches or is bigger than the head port shouldn't be a problem.

Tim