Great folks to deal with. A few years back we made the decision to restore our original, '67 R-code Fairlane Coupe to "day one". When the car was delivered it was adapted into an NHRA Stock/SuperStock competitor which meant converting to drum brakes/removing all the disc brake-specific parts including the brake booster with 32 actual miles showing on the odometer. With a limited resale market the decision was made to simply store it on a shelf in the shop. Fast forward to 2005, before re-installing all the disc brake parts the booster was sent to Booster Dewey for rebuild. Booster Dewey returned the original booster with a note saying that they had carefully inspected the booster and found it needed "nothing". They were so careful that I couldn't find any evidence that it had been opened and it still retained it's factory grease pencil marks from the OEM assembly line. The most unbelievable part of the story was they did not charge for the inspection also thanking me for permitting them to witness such a historical part in pristine condition. Every once in a while you are surprised when someone does something out of the ordinary.

I you have access to a "spare" trans slip yoke you could remove the drive shaft: you will, mostly, be doing that anyway when installing the new diff., install bare slip yoke in trans and re-run test as before. That will isolate or eliminate the trans as possible contributor. Good luck.

The alcohol content in today's street fuels is said to drastically shorten the life of neoprene lines without the teflon liner. My experience purchasing fuel lines has been that the teflon lined types are normally less than a twenty percent up charge over the plain, unlined, neoprene. Buy from a reputable source and avoid china imports.

There are a few different ways to restrict the oil to the valve train. One of those is restricting the oil coming to the rockers in the passage within the heads which terminates under a specific rocker stand on each engine bank. If reusing the head gaskets is a concern, then you may want to consider preparing the heads for the restrictors prior to install, that way you eliminate removing the heads for further work since it would then only necessitate removal of the rocker shaft assemblies to install the restrictors.

www.arp-bolts.com has an excellent resource available for using their fasteners. You can even call (800)826-3045 and speak to an engineer about any questions you may have regarding an unusual or specific application. I have found them to be one of the most customer-friendly organizations in the performance industry. Engine rebuild is an excellent time to make many of the changes you indicate as those changes can alter the machinists approach to some of the basic operations; i.e. replacing head studs vs. bolts.

 I would caution against "backing out" the screws (toward the bottom of the plate); they are usually very tight and backing them out tends to expand the  slot on the screw and, ultimately, lock them in place via interference. I have enjoyed much more success by simply applying penetrating oil to the top and bottom of the screw and advance the screw upward, toward the carb body (as opposed to "backing out"). In a few instances I've found it necessary to apply a small amount of heat--be very careful. Good luck.

I used "two" of the QuickTime plates. On the block side I used an unmodified plate while on the bell housing side plate I drew an outline of the housing flange interface and water-jet cut the interior away. To simplify later tear downs, using an empty block for alignment and solidly bolting the plate assembly to the flange, I tig welded the two together by tacking around the interior of the cut out plate. Proper spacing was achieved while limiting the overall weight.