If you have cast pistons, I might not go over 100 HP, with hypereutectics 150, and forged I have no fear of going 200 and up, if all the other pieces of the puzzle are in place. Main girdle support, ARP rod bolts and so on. I run a 100 HP on my 302, right off the line we are wide open. Never had a problem. Check my plugs after every pass. Keep an eye on the timing. 2 degrees retarted for every hundred horse. On my Coupe I had a Jacobs Mastermind. Came on real slow, and the flow of the NOS increased as the RPM's came up. Reached the 100HP level at around 5K. Compression ratio on both cars is around 10.0/1.
As far as the gear box, look at the Lentech AOD. They install a valve body, so it is a normal shift pattern, rather than what you describe. I run a ATI C4 in my 65 FB, but it almost never sees the streets, so gas mileage is not an issue. If you need more info on Lentech, I have some articles on their tranny's and phone numbers.
Ron
Almost forgot, I have a 68 FB on my site, you might get a kick out of...so far a 5 year project but almost done.
www.rfedd.bigstep.com
[This message has been edited by Ron1 (edited 03-31-2000).]