Anybody ever use them? 572's are being built and I have had a set of Lightnings on another boat and like them. Just wondering if they may have 311 measurements on file.

Another question. I will be ordering a set of Hydromotives but am wondering where I should start. Mills will be close to 700hp but most of my boating is done at 3600' elevation. Should I start with 28" or 30"? 1.50 Bravos

Bear in mind that if your 311 had the Silent Thunder box, the transom holes are cut slightly higher than "normal". I had to have 3 inch spacers made up from aluminum billet when I put my EMI Thunder exhaust on my boat. Be sure to run the water as far back, (seperate if possible) to prevent reversion. Those motors you are talking about are some serious stuff.

I'd probably start with 28's then tweak as necessary. Sounds like it's going to be one impressive 311. Keep us posted. Russ

Not sure about the 311, but I think the beam, center to center on the motors is the same as the 89 272 I had and if thats the case, the lightnings wouldn't clear, I ended up using a set of Bassetts to get the center clearance between the motors,the Lightnings wouldn't clear.(seems to me that the center to center on the 420s that I put in my 272 was 33".Its been a long time ago But for some reason thats the # that sticks in my mind.