So - pulled the deck - prepping to do stringers. Before I start hacking into the boat - I want a technical plan, to include motor/drive layout. Things I know.

1. Bravo gimbal setup and 350 motor
2. 350 - 400HPish

Things I don't know

1. Type of drive, Bravo 1,2,3
2. X Dimension
3. Stringer height or placement - (Based on X dimension)

Anyone have any thoughts or engineering know how to setup the boat properly? I am replacing the transom anyways so I have some latitude, but its dependent on the height of my stringers. I will need to factor all the dimensions in prior to rebuilding the boat structure. Any thoughts or suggestions?

Thanks!

Eric

Added a couple of pics...

Nice project.

The freeboard looks very shallow. You may want to keep the motor low & use a shorty drive instead of raising your motor.

B1 on the drive.

hmm - I was looking at a B1...So what shorty would you recommend? I have been looking at 1.5 gear ratio bravo upper. As far as the motor- What would the min space recommendation between the pan and the hull? If that would be a good recommendation, I can use that to set my stringer height...surprisingly the motor I have doesn't have an oil cooler. It has the cool fuel system and the power steering oil cooler, but no oil cooler. Something I may have to invest in.

I've had this boat underwrap for about 1.5 years waiting for the right time to play...finally got a house with a garage last april...so here goes!...


So with all that...whats a good recommendation for x dimension, or drive draft? Really wrestling with this one...

Keep it simple , xr upper Imco 2 inch shortie and tackle next project

that is a small boat. i think a Bravo will add unneccessary weigtht to the stern. alum manifolds and Alpha set-up will be a lot lighter.

Unless your planning on running more than 400 HP I'd run an Alpha SS, I believe the factory is about 7-7 1/2" below the keel, my 18 was 7 1/2" below factory with a Bravo, many are running Alpha SS's on the 16 and 18's with good results with more power, find ya an alpha SS and cut at the factory X and you'll be happy, might try posting your questions on Donzi.org bunch of knowledge there on the Donzi Classic's. No way do you need a Bravo XR with 350-400 hp in this hull, it only weighs 2,400lbs!! The Alpha SS will be faster than a Bravo and -2" and should withstand that modest power easily!

A thing to consider. Many things have happend with props since '74. The stock x has probably been around 14½". Very common x. I'd be very surpised if you saw any handling issues in terms CG if you raise it to 16". Then run a shorty. Either the Alpha SS, if you can find one,,, or the Imco -3. Remember, you can always space down when dialing in, it's quite harder to do it the other way around. Besides, the Donzis can run with high x dimensions. I know there's an 18 running an Arneson drive. All in all, use the prop technology available today and get the gearcase out of the water. If you do, your boat will be pretty fast for its size and power, consider upgrading your steering with either hydraulic assist or full hydraulic. The stock Merc steering sucks for performance boating and your narrow hull can have chinewalk issues if your steering is sloppy. You'll never regret it and you don't wanna swap ends at 70+ mph.

Sweet project. Keep us updated on this one.

I'll keep u updated...In the process of data collection and research. This weekend - looking at transom / stringer removal. At this point the drive will be a stumbling block. It pretty much determines the height of the strings.. So many variable....Thanks so much for the help and guidance so far!