Imco Lower
 

Can I purchase a stock length empty Imco SC lower and put in stock Bravo internals instead of an XR?

I know a lot of people on her are going to tell me it's a bad idea but I've had over 15 years of running including 10 poker runs using the Bravo's from 92 with out breaking gears/shafts. This is with 500 hp and ft/lbs of torque through the drive. I've had the drives once to be gone through and all they required was a seal kit, this was last winter.

I've witnessed and heard horror stories from people with new XR drives and I'd rather like to avoid it as I suspect Mercury is using lower grades of material in the gears now.

I also have 5 Bravo's complete sitting that I can use for parts if anyone of mine fail, so I'd really like to stick to the stock parts if that is at all possible.

Anyone done this yet? I know with some modifications you can mount a sportmaster to a regular bravo top half, and our local performance shop (not a small time shop but to stay anonymous myself I won't mention them at this point in time) has told me to avoid the XR and just use my spare uppers if I blow one anyways.

What are you trying to accomplish? Do you have blowout issues at high speed? If not, it'll most likely slow you down. Switching should not be a problem though.

New boat, it had nose cones previously for 500HP as it had blow out issues.

It's a 30' Regal Velocity, I'm going to put my standard Bravo's on it to start, how ever if I encounter blow out as is expected from the previous owner, I will be doing this swap over the winter if it's do able.

How fast do you expect to run? My experience is, that blowout usually don't occur under 85-90 mph. Maybe prop testing and setup could be the answer. It is doable, give IMCO a call, they will tell you what, if anything, you'll need to replace.

As long as you use the right vert shaft lower bearing and race on the vert shaft you could put ALL stock internals into a std length Imco lower, Smitty

The boat previously ran a best of 92 mph on GPS with 4 blade 30 pitch Bravo's. This was with 550hp 496ci big blocks. With standard drives, that were nose coned. I'd rather just buy a case already with a nose cone instead of dealing with the problems/head aches due to the Canadian winters that seem to occur on a frequent basis.

I am putting in my 427ci small blocks making 510 HP as a start piece so I can have the boat at a poker run in the next week.

Took this advice and slipped the boat in finally last night. I believe I have it over propped, but due to the engine bay being so long I can't time it, for proper rpms, and the gauge I was using kept falling off once we hit some waves.

I'm hoping my tach adapters show up today as they were stuck in Canadian customs, that will make this a lot easier.

What I did get though was 4600 rpm if I believe my tool. I'm going to try again with the tach adapters (I want to run 5500 for these motors), and 80 mph on gps.