Its the first thing noobie comp safari guys do they look at how much extra BHP is achievable (WoW) Its thrown away after the first event. Same goes for a Cams. I don't think well setup SU Carbs limit the V8 much I thought they were good for quite high BHP if setup right. The Edelbrock inlet manifold and carb is quite expensive and perfect for fast road cars no good when being thorwn around offroad or steep climbs and decents apparently. Splutters and dies. SU Carbs all the way IF setup right, engine given a good full service, slick 50, and a decent pair of filters fresh oil (TD oil higher temp range) that is more than most people do. If you did this every 6000 miles or less if you plan on taking it to africa. Good service will be better than most old spunky RR's and Disco V8's.
I am in a similar situation. I have a newly built EFI 3.5 engine that runs sweet but sitting in an 88 coil chassis. I have fitted to my 80 inch a 3.9 that will be on Su's (has been run previously but I've not heared it as yet) problem is somone spent £600 on the engine and fitted a "Kent Cam" Unfortunatly Kent make loads of Cams Fast road (High Rpm and no low down torque) and other cams more suited to an offroader (that has bags of low down torque but doesn't produce the power at the higher end of the rev range) and without knowing what one or measuring the lobes its impossible to say so I have to bolt it together and see. No doubt the bloke that built it saw the Achieveble BHP and went for the fast road cam which will absolute ****e for trialling. This is noticable when you watch some triallers Rangies because they have to rev the arse off the engine to get it to go anywhere. Whereas the offroad based cam will pull shead loads right at low rpm as low as 600RPM and will not die or stall. I'm no expert with this stuff just what I have picked up and it makes sense to me and have no reason to doubt it in any way.