Hi we started with a 220 rolls for the very first one then a 265 then a 290 which i was told wouldnt go in but it did of coarse as its the same block.It was early days then with the conversions rolls engines were cheap and plentiful. The 290 waqs a bit large power wise but if you were sensible it was ok, i sold one to a guy that i had run for 2 years within 3 weeks he had smashed the diff and broke the gearbox rear mountings.Any engine will go in within reasonas for adaptor plates the petrol bellhousing bolted up to the rolls the biggest problem was flywheels and clutches.If i was going to do one today i think i would use a 230 gardner which is basically a 201 which is an uprated 180 with a blower on, but having said that i am a gardner fan.Mike