Springs hold to 7000. Obviously my local machine shop is a little rough with the bore though according to the vac readings. Drops off bad at 7200 and its still making power. Guess you get what you pay for. Torque plates work laugh

On another note, tech'd and waiting to race.

1971 Plum Crazy Super Bee. 572 World Aluminum block with a Cope 727 & Dana 4.10 out back. 9.88 @ 138 with a 1.35 60 NA. Dialed back to 10.0’s. 4000 lbs with me in it.