Before turbocharged cars became so popular ,people who had normally aspirated cars and wanted more power mainly went down the route of higher compression engines, stage 3 cylinder heads, hotter cams,free flow exhaust manifolds and twin side choke webers or dell-orto carbs. It was a tried and tested method of getting more power and when I first started modifying my 2wd Saff 25 years ago I was suprised when the tuner said he would be lowering the compression ratio to get more power!! It seemed at the time strange to me but was the accepted route to take with a YB engine. Times have changed and turned full circle with some people now building high compression YB engines. No doubt Mark Shead will be able to explain why?