Most of the conversions concerning the engine mount utilize a flate aluminum plate that bolts on over the existing rear cover. On this original rear cover, all the plastic is cut away even with the outer edge of the engine block. Warehouse hobbies and other boat people make a complete combination rear cover and mount that is actually made for boats and the mounting portion would have to be modified.

The best model of Walbro is the WA167A with a 7/16" bore. There maybe a used one that has a 7/16" bore that you may be able to obtain locally used a little cheaper? Don't go beyond a 1/2" bore.

The C-H will not give you any noticable amount of increased power but it will save you a little weight. All the 25's & 30's I've seen including my two have the original magneto ignition. The excess part of the plate behind the flywheel is removed. I have C-H on my McColluch conversions though.

The engine is going to weigh a little over 3 lbs.

Enjoy,

Jim