You need to have new valve seats put in, if the springs are old I'd replace them as well. Most people have had good luck with the 75 or 73MM maf. I've got the 75 and I think it's just right and I'm using F/I on my car to boot. You could always send the heads off to Kinger and they can do all the work of the valves plus do a full port and polish job to really make it flow.
Rick
