The 1009 bore size was originally design for the 426 and 383 4.250 bore size so they are marginal to no good on 440 and 400 blocks bored over size scope twocents
I've used a bunch of them with no problems on the deck sealing with out the receiver grooves they, Fel Pro, recommend when using them up

Last edited by Cab_Burge; 09/29/20 02:03 PM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)