If it was me and numbers your talking of running I would build a methanol injected one building your own manifold and build a flying toilet type deal, Wayne on here built one for his 305 pretty neat have a look on his build thread on here,or stick a shot of gas in it as plenty of off the shelf bits, along time ago I remember getting 350hp out of a sdi unit and perks was the same weight as the pinto it replaced, just remember rovers have a lot of choice with compression, heads etc and cheap ish, if you want to stick the magic in it the cast stuff has to go me and my brother were looking to do a nitro rover fc but gone for different engine but still not the normal if you know what I mean good luck dude.