I drove it with the Holley 750 today. It detonated at the same point as with every other road test!

I'm unsure of how I'm supposed to plumb a fuel pressure guage to see it while driving. Am I supposed to remove the hood and run 4 feet of hard line over to the windshield?

I have a few ignition ECUs I can try to see if they make any difference. I am a big fan of testing free parts. I have a Rev-n-nator ECU that I tried last year. kinda funny...I pulled it because it made the engine knock MORE than with a stock ECU at the same timing settings!

Regarding carbon buildup: I guess it is possible, but I did have the engine apart in 2011. I've put about 3000 miles on it since then including 2 road trips of 1000 miles each. If and when I pull the heads, I'll have them ported while they are off. I've wanted to do this for years but always went cheap and skipped it.