Could you use the B1's and just not set them on kill? OU812 did a thread on some basically stock B1's (mild cleanup, valve job etc) that kept a reasonable port volume, but still flowed alot of air (380's?)that you wouldn't have to spin the day lights out of your 499 to make good power. That way when you get your aftermarket block you can set them on kill at that time.
Edit: here's the link
https://board.moparts.org/ubbthreads/ubbthreads.php/topics/105599/1.html I own the B1's you speak of and I chose to put a new set of indy -1 325 on my 512. My plan is an all aluminum 588 with the B1's eventually. However it is going to cost me close to what I paid for the -1 just to get the Jessel rockers fit correctly on the B1's. If budget is not an issue build a big one that can can utilize the big big runner and will run clean on the stop. If not stick with a smaller head and go out and kick some Chev 632 butt!!!!!!
I don't know how Sheldon Gecker used to do it back in the day with the King Kong Daytona. It is my understanding he ran small cubes and big B1' Heads?????
I bought my - 1's of Dwayne and he reused all of my valves and springs to save me a few bucks! Worked out great.
