Got myself an untouched 12g295 head, no cracks, no skimming done - completely untouched - unfortunately no valves or studs in place.
I'd love to put it on my 998 soon( will probably do a complete overhaul: rebore +60 and sw5 cam, lightened internals) which would mean cleaning it up, but until then I'm interested in doing some porting/cleaning up of the casting marks and some basic flow optimisation via david vizard.
I know the 295 casting is already very good and Ive read the posts from russel on modifying a small bore head and I am aware that the 295 head has some more critical areas to be wary of, but what I would like to know from the experienced guys here is if it is worth it on a 295 head to do extensive work or should I just get a 60 grit cone and clean up the insides and remove casting marks?
How much more "value"/flow/power can be achieved by doing a top job on a 295 head vs a "clean up" and is it worth it? I'd like to do as much as possible myself, but the guy who will install larger valves for me COULD do some proper porting at a cost - hence value vs. reward?
Since the valves are out and I will be converting it to an unleaded head, I was thinking of increasing the valve sizes to something close to what keith calver does. 33.3 REC121 inlets and 27.2 exhaust valves. Any thoughts on this or other recommendations?
Anything else worth mentioning?
Anyone have some good articles to read about 295 castings and porting them?