Good Morning Everyone,

I have a 26' 86 Nova 2 with twin merc 350s and Alpha 1 Gen 1 drives. I just pulled the starboard engine due to having 0 compression on cyl #2. I pulled the head off last night and found a bent exhaust valve. I am looking for a little guidance as to what others have done. I am toying with the idea of an off the shelf ready to run aluminum heads (AFR or Dart Pro 1) since I don't have the GM Vortec heads. I want to pair this with an aluminum intake manifold and an Edelbrock 1409 600cc carb. My question is, is do you think its worth the money? Any noticeable power gains? Does the extra power affect the reliability of the Alpha one? I read they only are rated to around 300hp. I was planning on leaving the bottom end stock if all looks well, just a hone, cleanup the pistons, new bearings, rings ect. The boat maxs out at 55 mph. Id love to get a little more out of it if I can whiles its out, and then do the same build to the port side engine in the spring. I'm torn between putting a little bit of money into the boat if there's noticeable gains, or just get a head job and slap it back together.

Thanks

Dave

First thing I would address is why the exhaust valve bent. It is likely from a leaky exhaust manifold which can rust the valve stem causing it to stick, hence PTV contact.

An AFR or Dart Pro 1 head is a lot of money for a stock bottom end. I would not do those heads unless it was a bottom to top build with appropriate cam etc.

it's a boat so 10 or 15 thousand should net you around 3 or 4 mph gain so to me it is not worth it. best money if you are wanting to change heads is go to a vortec head and aluminum intake. smart money for now would be to just get the heads redone right and go enjoy it.

If you are not going to do a camshaft and other upgrades to the bottom end then you will probably be very disappointed. How many hours on the engines ? Are they using oil ? If not I would leave them alone and get the heads rebuilt and get back to boating. And like Trash said the first thing you need to do is find out why the valve stuck open and got bent.

The Gauges show 200 hrs on the boat. From what i was told it spent a lot of its life on a trailer in a barn. I've owned this boat for 3yrs now. Haven't really done anything but routine maintenance The engine is very clean inside so far, doesn't burn oil. I plan on machining some blank off plates for the exhaust manifolds over the weekend and pressure testing them, per Trash's recommendation. The only thing that was really "wrong" with this engine was someone put a Holly 750 Street car carb on it (port side is factory Rochester carb) and its been running super rich. I've been planning on converting both engines to the Edelbrock 1409 600cc carbs. The boats been running so i kept kicking that can down the road, so that's definitely getting done. I do not see a witness mark on the piston which is a little confusing to me. I would assume I should see something from a valve hit. The valve is maybe 1/16" from shut. I appreciate all of the feedback. You guys confirmed my thoughts on the head situation. Going to get some quotes on a head job and fix what I've got. Sometimes its hard to talk the gear head out of me and do the sensible fix. I've thought about doing a cam but only if needed i guess. I cant say this will be my forever boat so I am trying to balance how much money I pour into it vs performance out. Id love to hit 70 and that will never happen in this boat.

The valve might have just stuck open. Usually that is from running lean but it may have been a little tight from the factory. Or if it has been running real rich it could be carboned up. The Vortec heads are famous for the intakes sticking due to the valve guides being too tight.

I am doing a set of those heads right now for one of my Marina customers and they are going to have about $400 in the pair but they were in kind of crappy shape. I cant imagine yours being any more than that. Your machine shop can measure the guides and do what is needed to get you back on the water.

Usually if there is water coming in from the manifolds it is pretty obvious. The exhaust ports in the heads will be rusty.

Personally as far as the carburetors go I would try to find the correct Q-jet to match the other engine. You really cant find a much better carburetor for that application.

Good to know Bill, Ill see what i can find on FB Marketplace or Ebay and just rebuild them. The port engine runs fine with the factory carb! If it isn't broke don't fix it! As far as the valve goes its the exhaust valve that's stuck. I haven't pulled the valve out yet. Visually I haven't seen signs of water from the Head gasket, exhaust manifolds or intake manifold. No rust in the exhaust manifold or exhaust ports on the head.

You will likely not see witness marks on the type of PTV contact I commented on.