budget drag strip car build Q's
The J-heads were port matched to the Performer intake? So did he braze them up to make them smaller or open up the intake? The regular Performer has 318 size ports and small runners. The first thing I would do is eBay that intake and either get something better. A Performer RPM at a minimum or a good single plane like the Torker II or Strip Dominator would be a better match to your goals. If this isn't going to be a street oriented car, definitely run the single plane. With 4.10 gears, a GOOD converter, and moper's cam advice, you should be able to get into the 12's no problem. Don't even think about a spool if you are going to put license plates on this thing. A Sure-Grip and SS springs should be plenty to hook up that combo with sticky tires.
Cast pistons are the limiting factor on your short block. Shoot for 6000-6500 RPM.