Hey all...I'm a newb with the boating scene, I have owned several boats but never had them in the water but had intentions of doing so...I've had 15'-42'...and they all needed work...my newest boat is a 36' Doral 350SC. It has twin 7.4 big blocka that appear to be stuck and not able to turn over.I pulled the head off the inner starboard side and found a rusty combustion chamber. All other cylinders appeared to be in decent shape except that one particular cylinder but that's just one side and another engine to go...my question is I'm looking for a setup better than what I have with it...I'm good with the 7.4's and not looking to build a hot rod motor...mercruiser has square port intake and the small oval port heads. Is there a stock configuration that can be used and not have to run the guts out of the engine at a high rpm. I always messed with small blocks and know nothing about big blocks and what years and configurations breathe well together...the boat weighs around 12k the motors have 725hrs and the cam valley appeared to be super clean when I pulled it apart...Ohh and has bravo 3 drives on it. Not sure of the ratio or prop pitch but I would assume whatever stock configuration was with that boat from the factory...it's a 96 model year and came from the Chicago area and was floated/driven to Jackson FL several years ago and then dry docked for 2 years and sold due to storage being owed...any suggestions???

some pics to start would probably help.

Run the guts out of it at high rpm??? You have a cruiser with bravo 3's, how fast are you trying to go?

The merc 7.4 should spin about 4600-4800 rpm all in, if your hitting 4800 rpm you might try going up a size on props but on a pair of Bravo 3' thats going to get pricey. 750 is getting up there, rebuild the motors stock, check the exhaust carefully, put it together and enjoy it. Its a boat, its going to spin some rpms

I'm not gonna bs...not sure what rpm's it's gonna spin. Just kinda wondering if there is a better combination now than what it came out with in '96...I don't intend to run it hard or build it to be ran hard...I want to enjoy but update what can be...I do have to replace the manifolds and risers as they are full of gunk and corrosion so some info/knowledge would be gratefully appreicated. I can turn a wrench but not familial in this field as to which products will be best suited...thank you for any input

As for the exhaust is there a good better best option for the manifolds and risers...and since i will be in salt water is there any prep I should consider before installing. I was wondering if glyptal would be an option to help preserve the inside of. I believe i read somewhere it's a good idea to replace manifolds and risers every few years. Is this a realistic suggestion???

Baja...boost is nice but on the water (for me) it's about kicking back and relaxing or least trying to get there...I like working on things, but only once. I don't believe a performance build is for me on this project but if I can find components that can help it breathe better and work more efficiently then I am game. I'm having a hard time coming to the realization that I just need to pull them and go through them. The small oval port heads and rectangular intake is just baffling me and seems like there is a better stock option from previous years that can be combined. But those guys at Mercruiser has blown up more engines than I have testing what will and what won't work...should I leave well enough alone and just run that setup?