In my 69, with 351w I'm running the
67/73 SMALL AND INTERMEDIATE BLOCK, 390 TO 520 lbs/in
I LIKE EM!
I've got the TCP subs and x-brace, 1 1/8" sway bar with all polygraphite bushings from PST, and the 17" wheels - and it goes through turns sooo nicely.. I haven't done any hard turns over 40 because the back tires start to rub. If your car is mostly street, I don't think you can go wrong. I compensated by getting the bigger sway bar - this way going straight I can get a little more cushion, and when I get into the turns, I figure I'll let the sway bar do its job.