The above item must comply with the Historic regulations regarding period modifications. To be more precise the manifold must be as used in rallying in period. This would include bore size, shape and configuration.
In all cases the onus of proving a modification as being period rests with the competitor who must submit the required documentary evidence if required.
Ford Escort BD Exhaust Manifolds.
There are a number of manufacturers of the above manifolds. These vary in shape & size. The method of connecting the individual pipes vary also. They may be connected by sliding joints which may be a spring or bolt fixing
The pictures below are of a manifold clearly showing the individual pipe configuration. As can be seen in picture no 1. Cylinder 2 & 3 outlet pipe’s exit the cylinder head and passes over no 4 outlet and then go down.
Number 1 & 4, 2 & 3 join together to form the 4 into two and then two into one outlet.
There are manifolds that clearly do not comply with the period specification.
The pipes rise up from the cylinder head and then down. They resemble a bunch of banana’s.
This manifold has not been proven to have been used in period.