Commodore

There is a ebay ad that says that it is for a V-8 Oldsmobile or Pontiac engine. See link. http://www.ebay.com/itm/Nicson-Marine-rear-motor-mount-101-14-Oldsmobile-Hardin-Marine-feet-jet-boat-/161573360674

Well, there are these guys, Rocker Arms Unlimited. http://www.rockerarms.com/

Then and Now Automotive can rebuild your mount. http://then-now-auto.com/nors-vulcanized-motor-mounts-rubber-products/ Here are some photos showing how they do it. http://www.picturetrail.com/sfx/album/view/8316977

This is the one you say does not fit. Are you sure it's not just stuck together with rust?

Well, I can tell you that there were 39,200 V8 Biscayne's sold in 1966.

The 1954 Packard was positive ground.

I think this is the car he is speaking of. As far what its price goes, there is no price guide on the Biscayne, too rare. The price for a 1969 Impala hardtop coupe with a 327 is given as $11,266. This by Hagerty Classic Car Price Guide. I would not restore it. A car is only original once. http://www.ebay.com/itm/Chevrolet-Bel-Air-150-210-Biscayne-1969-biscayne-327-all-original-48-k-miles-rustfree-barn-find-no-/321563311780?forcerrptr=true&hash=item4adeaabea4&item=321563311780&pt=US_Cars_Trucks

It's for Ford Six Cylinder COE and Delivery trucks. 1950 - 51 F3 Parcel Delivery (H engine) and F5 and F6 COE (H engine).

I can tell you that GM discontinued that part in November 1990.

It looks like to me that these tanks were never used by a OEM, just aftermarket. See link a description of operation. http://books.google.com/books?id=HFLmAAAAMAAJ&pg=PA500&lpg=PA500&dq=Byrne-Kingston++tank&source=bl&ots=VgIgvkgIWO&sig=NzuqhzlKmFC6IC6Sqa_oLYUTkBY&hl=en&sa=X&ei=8rNNVKfaHozwoASW3IHgAQ&ved=0CCMQ6AEwAQ#v=onepage&q=Byrne-Kingston%20%20tank&f=false

OK, here is the Front.

You might try these people, SMS Auto Fabrics. http://www.smsautofabrics.com/

The problem with it being 1942 Pontiac is that the bezel is different on the 1942. See photo.

See this forum post. http://forums.aaca.org/f169/valves-guides-316495.html

Herschell-Spillman also made a V-8 with 3" or 31/4 bore and 5" stroke. See link for an article on it. http://books.google.com/books?id=sotMAAAAYAAJ&pg=PA928&lpg=PA928&dq=herschell-spillman+engine&source=bl&ots=O0BE-MlCld&sig=Bjn5h8STYqTlPalUYNI2TVHbibo&hl=en&sa=X&ei=IOA9VLbgJsngoASB64CADA&ved=0CEwQ6AEwCDgK#v=onepage&q=herschell-spillman%20engine&f=false