I've used nothing but fishing line for years. No gasket sealers at all on Chevys and Oldsmobiles. Just pulled the pan on our 440/512 to replace leaky rear main seal,,,ended up using Mancini/440 source retainer setup. 2 hour job turned into 8 or more. First getting the pan free because the guy that put the motor together used blankety/blank ultra grey,,,and then a few more hours cleaning the crap off the windage tray,the block and the pan,,,a big pita.

Putting it all back together I left out the windage,,,damn going to lose 15 hp at 6,500 rpm,,,and just used the fish line thru 4 bolt holes to hold the gasket in place,,,,which is cut and pulled out when pan is buttoned down. If the rear main leaks again, wiil be a couple hour job.

Problem that I now have is this. I used a Milodon crush proof gasket and arp bolts torqued to 15 pounds. After a few miles of driving, had leaking at rear of pan. Checked bolts,,, all had loosened to less than 5 pounds. I re-torqued and again all soon loosened again. I then tried Permetex number 243 blue thread lock,,,supposedly works in the presence of oil,,,,don't believe it,,,did nothing even after cleaning bolts and bolt holes best I could with carb cleaner. I pulled and cleaned and replaced each bolt one at a time. Loose again.

So now rebolt again with lock washers, pitching arp's regular washers,,,they now seem to be holding torque better,,,,was wondering if so called "star" washers might hold better.

However also the Milodon gasket is squeezing out a bit at the backnear the flywheel cover,,,,and has cracked at a couple of the rear bolt holes. And is oil logged, so am seeping a bit of oil,,,so will be changing it out for another solution. May give the "Performance" gasket a try. It appears to be getting good press on this forum.

Overall a real PITA introduction to big block Mopars and oil leaks,,,,,I do own a 1956 Chrysler 300 B,,,and in 28 years has never leaked a drop. Wonder where those engineers were hanging out when Chrysler went with their wedges and 2nd gen Hemi',,. Christ lost my head again,,,,,the 1st Hemi's were rope sealed.

One other thought on pan bolts loosening. I said earlier that my engine is all bolted together with ARP. These appear to be stainless bolts. I am wondering if this is why the pan bolts will not hold torque(using a high quality Snap On torque wrench). Stainless against the cast steel of a oily block may not give enough friction,,,if against stainless all perhaps would be far better. I plan to call ARP to get their opinion. As to possible issues.

The Mopar pan is so simple( all flat design) compared to Olds or Chevy,,,have not figured why it is so tough to seal, whereas I've never in 40 years had leak issues with them. Is it the design of the mating surfaces,,,or again the arp bolts,,,or the Milodon anti crush gasket? Pan and block surfaces were totally and perfectly clean and pan surface was completely flat. Interesting how Moroso gasket has partially squeezed out at rear,,,but does not explain continuos bolt loosening. Leak is minor at this time and occurs only after mildly hard driving. But still should be zero.

Likely I will post a new thread(with even more detail)on this topic to get some opinions. There are some sharp minds that I have seen since joining this forum,,,someone(s) know..