Conversion to V6 is pretty straight forward as the engine is an option Gerry offers. Assuming the chassis isn't set up for it he offers a conversion kit that consists of the V6 mounting brackets for the chassis (3 off), the brackets that bolt to the engine (2 off) plus mounting bobbins and brackets for the engine steady bar. The gear linkage upper mount needs repositioning too. In addition there are two spacers to mate the Alfa driveshaft flanges to the Beta driveshafts. You'll need a new exhaust system and engine management system too. If you need a recommendation for these changes there's a fabricator in Widnes who has done a few now.

Guy