Hi Chuck...sorry I didn't see this post earlier this month until Rick posted to it.
I suggest either the BHJ Dampner or the Innovators-West Fluid Dampner. The innovators-West has 360 degrees of timing marks and the BHJ has sufficient for timing. Both are SFI rated and serialized. The only additional machine work for the Innovators-West is removing .400" from the front of your sleeve behind the dampner so the pulleys will be in aligned. It's not rocket science. The 427 dampner is neutal as is the flywheel. Both of these dampners have the correct three bolt pattern for March Pulley systems too. They both have crankshaft bores that are slightly smaller than the standard snount on your FE crankshaft and the shaft has to be measured and the dampner carefully fit for the correct press. Also the Innovators-West requires a .400" longer 1/4" key. (any hardware store for 1/4" keystock and a hacksaw/file)
Innovators-West is manufactured right there in Kansas!
http://www.innovatorswest.com/
Regards, George