RECEIVED MY BME 50 TODAY FROM CHIEF ,HAS ANYONE USED THE STOCK ENGIE MOUNT FOR THIS ENGINE IN THE EXTRA . IT APPEARS THAT IT WILL WORK WITH A LITTLE DRILLING. THE ENGINE LOOKS GREAT OTHER THAN THE RUBBER SPARK PLUG BOOT, I ALREADY CALLED C&H AND GOT A BOSH CAP AND MODULE COMING. I'LL SAVE THE STOCK ONE FOR A SPARE

I have had no problem with interference with the standard boot. The ground strap is clamped to the spark plug body. I thought about using it but my engine came with the H9 alum mount and you still have to shim the GP mount a bit from the firewall. I probably would have used it as it looks like you only have to widen the holes about an 1/8"

You might want to check the stiffness of the GP mount, it tends to flex to much for my taste, with a large engine mounted on it.

I used it to mount a ST 3250 on my H9 Taylorcraft (I was looking for something big enough to mount it on, but it was a bit over powered), seamed like an ideal match, and lighter than the H9 Aluminum mount that came with the kit.

HOWEVER, when I ran the engine up, the whole air frame vibrated and rattled (like stiff plastic of a drum skin) quite excessivly once I left the ground.

With it sitting on the ground, you could noticably flex the engine from side to side about a 1/2" at the spinner, and every bolt was checked for tightness! I even checked the fire wall as well, which is almost a 1/2" thick.

This engine (ST 3250) might be a little to big for this mount, or something about the combination of engine and airframe, But when I switched back to the Aluminum H9 Mount, there was less vibration, noise, and almost no flexing at all.

My advice would be to go with the H9 mount, based on my own experience, but your's might be different.