Bit of interesting XPAG engine data / tuning information here
http://home.modemss....seley/xpag.htmlInteresting that the standard MG TC engine only had a max of 54 BHP and even in full race guise a max of 83 BHP pretty poor even for a 1250 cc engine given that it was quite a tall ( seemed to need a bulge in the bonnet of a VI to clear the rocker cover ) and large cast iron power unit.
Even the 1500cc version the XPEG in the TD2 and TF was only worth an extra 11BHP from its bigger bore.
"Most of this difference - which, believe it or not, could be felt - was due to a change from 3 cm SU carburettors to a set of the same make with 4 cm venturii, coupled with a raise in compression of 3/4 of a point or a jump from 7.25 to 1 up to 8 to 1.
Slightly stiffer outer valve springs were also used. The XPEG engine differed from the late XPAG only in bore size, a core change allowing a bore of 7.2 cms used in that block as against the 6.65 cms of the earlier model.
In virtually all other respects the XPAG and XPEG engines were the same, even unto the stroke. Flywheel horsepower of the larger stock engine was listed at 63 at 5000rpm, though careful balancing and selective assembly eased this up to about 65 maximum at 5200rpm.
One of the nicer aspects of the pre-1956 MG engines is that power increases could be made in small, easy stages governed mostly by the energy of the builder and the state of his bank account. There were actually five operations, or stages, of power increase for either engine, the final or full-house treatment delivering about 85bhp at 6300rpm on 90 octane fuel. With alcohol this last operation could produce well over 110bhp at the same rpm figure, using the smaller 1250cc engine as a base of operations."
Peter Gammon (1500cc Lotus-MG) shapes up to pass Clive Clairmonte in the 2 litre Clairmonte Special in 1954 
