Rubber mounts

Hi Guys. Doing a mini cleanout and found two unused rubber mounts with "C538-276B Jul 88" stamped on them. They are approx 3 1/4" diam. The rubber part is 2 1/4" long and bolt end to bolt end is just under 5".
Any idea what they are for? Thanks. Rod.

Are they Mackay parts? I'll take a look in my Mackay-Silentruba catalogue to see if those numbers come up .. a pic would help ..

Blackwoods have those things,mind they are ruthlessly inefficient (Blackwoods that is).You could also go to the wreckers and get them off Hino exhaust stack mounts.They use them as isolators,they are good for mounting small petrol engines (like a 5hp Honda),and they also use them as exhaust mounts.The bigger they are,the bigger the thing you can mount on them.

HC - I've searched through all my Mackay-Silentruba and Kelpro catalogues and come up with a blank. Even the P/N cross-references don't show anything like that P/N. There are similar size and shape Mackay rubber mounts, but they appear to be slightly different in dimensions. Surprisingly, neither Mackay nor Kelpro give any info on dimensions .. just pictures and P/No's.

The Mackay and Kelpro part numbers are a pretty basic "letter followed by 3 or 4 numbers". All the Mackay P/No's start with an "A". That P/N almost looks like a Ford P/N, but it's still not right.

Best I can suggest is that the mounts are a heavy duty isolater for specific useage either on exhaust systems, tanks, or small engines .. and they may be a product of some overseas company.
The P/N indicates they possibly could be off a Jap or even an American or Australian truck, and they're for a specific use on that truck.

Volvo (Australia) used that sort of part as gearbox mounts on the 86 & 88 when making non standard arrangements, such as updating to 16 sp box in 8 wheeler etc