This is manifold has had a high performance coating applied to it.
Standard bore LCB (1-3/4"id) that is ideal for very hot small bore engines, for standard to high performance 1275's and for street 1380's.
There is NOT enough clearance room when fitting to old cars with rubber couplings which foul. Using QL5000 type couplings will help but reshaping of manifold is still required in most cases.
Also available is a Stage 2 manifold with larger centre pipe for increased engine capacity, see C-AEG376.