[bigblockv6]

The way everything is setup with spacing, mounting, bellhousing clearance and clutch assembly the flywheel can only be specific for the GMC V6 light and medium duty applications. Yes possibly a Hyster Forklift equipped with a 305 or 351 V6 may have a correct flywheel. I had a custom flywheel built for my 478 to fit the light duty bellhousing and you would be surprised all the little details that had to be correct in order to make it fit. The flywheel manufacturer didn't machine a relief area on the flywheel to clear the four inner mounting holes from the front of the bellhousing to the engine block, luckily I was able to grind down half the surface face of each bolt to get clearance. As far as the Caterpillar valves go those are an alternative to replace the large hollow stem sodium filled exhaust valves used on Magnum engines. The stock valves can easily snap from over revving and that's why governors where installed in big truck applications. At one time I had a list of Cat valve part numbers but they're gone.