Head help....

i tried to duplicate your engine on the computer-dyno and it seems to me that your car set-up, including engine, is very efficient considering the specs given. that tells me your current heads are very good and might have been worked-on like porting/milling (??). but even in spite of this, substituting a set of stock edelbrocks in place of your j heads in my program, i believe your car could go 0.1 second faster in the eight mile or slightly better with them .
I did some some work on the heads. I opened the intake ports and smoothed them a bit after gasket matching. Cleaned up the bowls and exhaust too. Maybe the work I did helped more than I thought it would. I still wonder if more timing wouldn't have made a big difference. I think it was set at 32 degrees total all in at 3 to 3200 rpms.