I have a Chris Craft Stinger 390, i was thinking about changing drives on. I see #3's on here pretty cheap, what do i have to buy other than drives? Will my transoms work? Should i run something else, or keep the originals. I plan on running 650 to 700 hp. I guess a better question would be what would it take to get it up to 75?

What engines and drives do you have now?What props?How many rpm will it turn at wide open throttle with those props?

500 hp 468's,23 mirage, and it is supposed to run 61 right now, I have not checked it yet. IT is turning 4800 rpm. I have some motors in can get my hands on that would make 650.

With the 23P props you would have to turn 5800 rpm's to see 75mph.That's with 1.5:1 gears and 10% slip.25P prop 5300.What drives do you currently have on there and what gear ratio are they?There is a site called PROPGODS.com which has a prop calculator you might want to play with.Whatever rpm you come up with your going to need the engines to put you there.4800 rpm with the 23's should be right at 62mph.

They are the stock trs, they have been rebuilt. i can put the motrs in front of it but don't think the drives will hang. i am not sure whether or not to put speedmasters on it or not.

I always heard Mercury rated them good to 550HP.However I've heard others say their good to 650-700HP.I guess it depends on how you drive them.Hard takeoffs in a big heavy boat kills them.I think I would stay with the TRS's ,put nosecones on them and different engines.If they don't stay together you can always up grade.

I with you on the try it and see if it will hang deal, but i know where a complete setup for 3's is that i can get for four grand. I think the drives and transoms i have have value probably enough to buy the other setup. I am trying to get some different opinions. I am also curious how much power 3's will handle. I have a buddy that races, so i can get decent deals on motors they outgrow.

In order to go to number 3 drives, you will have to replace your transom assemblies with SSM style transom assemblies, the TRS are different. ALso, the transmission would need a ssm tailstock, again different from TRS. Then the engines would need to be moved back a inch or two i believe. While doing all this, you would probably want to raise the propshaft heights to see any performance gains. The TRS propshafts are probably well below the botom of your hull. With props today, you can take advantage of higher drive heights.

It would be a project. Not that it cant be done, as it has been many times.

Now, if you went with Konrads, they would bolt on to your transom/gimble housing, and be stronger than a #3, and also would raise your propshaft, which might be worth 3-4mph just by itself. If your gonna go that route, i'd get in touch with "biggus" on here. He works directly for konrad, and is very knowledgeable when it comes to the TRS/ konrad conversions.

That 4 grand i was talking about was trannies steering and drives, and transoms. I wonder what konrads are going to set me back?

Konrads are 9K each.Drive only!! I think if I could get 2 complete #3 set ups drives,trannys,transom assemblies for 4 grand I'd jump on it!!