Salv Sacco has been one of the main guys building engines though he is now semi retired, based in Brum. His 1550s are based on a 1397 5G Atmo engine built up in a 5GTT or Volvo 343 block (these still have the lugs on for fitting the transverse rear engine mount for the 8G Salv uses his own stepped liners that require the block to be machined to fit. There are other 1550 kits now available that do the same as well as low comp pistons for use in turbos. It is also possible to fit one of several stroker kits that are using Dacia cranks that will allow 1700cc to be reached.
the original 8 motors are different to the 5 motors and a 1255 Gordini lump with original head is a sought after motor as most of them were snaffled up and fitted to '85' spec Alpines that had the 12TS type engine fitted, hence the premium for an original motored 8G, though from a driving perspective the 1550 is probably better!! (and easier to repair or replace!) A Salv engine is a strong selling point for any R8 or A110 Alpine, he is THE MAN!