I'm ready to put the lifter galley plugs in my 440 and I can't decide which sealant to use. The last thing I want is to have a leak between the block and trans. I really like the old Indian Head Shellac, it dries solid and I had to heat it with a torch to remove it in the past. Or should I use some fancy expensive Permatex thread sealant 521 good up to 10000 psi. The thread sealants all seem to say they stay pliable...is that good?