Mark (Vortecpro) 355 makes about 440hp and 450tq.
I had a modified version in my 65 and it was sweet!!!
Not sure he is doing them anymore but it would be worth checking.
Mike (Wolfplace) is another one that may be able to do something for you.
As far as a lot of these other "internet companies" out there be careful.
I have been burned twice (for a lot of money), and I know Mark or Mike can be trusted to deliver what they promise.