I was finally able to catch up and talk to my friend that races these Generac engines. He posses a wealth of knowledge about these engines.
First of all, Generac designed and built this engine from the ground up in-house. They then sold the design to Briggs, who then marketed them under the Vanguard brand. Generac continues to manufacture the engines used in their own generators. This is the only V-Twin big block still being made in the US. They use 6 bolt heads. The 4 bolt head V-Twin engines are small block designs, manufactured by Briggs. All other similar size engines (Kohler, etc) are being manufactured overseas. Back in the day, Generac used to sell engines directly, but their sole focus these days is generators.
Generac has a policy of replacing engines under warranty instead of repairing them. My friend was able to pick up a GT-990 engine with 12 hours on in that had been replaced under warranty. The only issue with it was a minute leak from the crank case gasket. It wasn't even enough of a leak to cause oil to run down the block.
My friend and his dad get these engines, and then discard everything but the block, crank and bare heads. Then they bore them out and put in larger pistons, valves, valve train, etc and set them up to run 15:1 compression on methanol. They also discard the OEM ignition coils and run dual Bosch blue coils with dial Mopar racing ignition boxes with individual crank triggers for each cylinder. Spin around 9500 rpm.
At any rate, he's willing to swap out my entire engine for the 12 hour one mentioned above (was pulled from a 15kw generator just like mine) with some "boot", but probably less than what I would have had to pay for a new set of head assemblies. The only thing missing is the oil pump and pickup tube, which I can steal off my engine. Even has a new crankcase gasket I believe. Woohoo!
