If its for a road car just dont have straight cut gears they will drive you nuts!! if I was you I would go down the T5 route which will be much cheaper than Quaife internals? There is a Class A Morgan running in the Morgan Challenge race series in the UK which is pushing out about 360/380 BHP quite happily on a T5 but this would be very close to the limit!!!
Talk to Peter Mulberry at Mul fab he can supply the bits to connect the T5 and might even have a box?? (UK) 02476 397666 or pmulberry@aol.com
www.mulfab.co.uk
Racer