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looks like that to me good luck finding a match!

I wound up measuring mine, it was .010, which isn't bad, as long as I don't have a hunting idle I'll leave it be. BTW, I have found that when adjusting the fuel mixture on a Quadrajet, you get a better idle when you first get your curb idle down to about 600 rpm, to make sure that the engine...

More on Chevy 4.3 casting #s, I think the ones here are just the last 3 digits of the longer casting #, pulled this off of an ad selling reman cyl heads. Casting # is 3rd column from the right.

look here you can find your engine casting # and match the OE cylinder head you are keeping to the casting # in that list to figure out what you need.... https://forums.iboats.com/threads/complete-history-of-the-4-3-liter-with-casting-numbers.693935/ thanks to Scott for putting that together....

Compare the casting #s of the heads, you want a pre-Vortec head to match the other side, assuming it is OK. Now if it's a pre-Vortec head (look at the pick of mine, you'll be able to tell easily) but the casting #s are different, I'm not sure about the rocker arm mounts, I think we have to...

How to do a running test; be careful with the hose clamps watch out for leaks!

I would: Hook up a vacuum gauge Get some light motor oil & a squirt can Run the motor & squirt oil around the throttle shaft for the primaries & observe the gauge. Do the same with the carb gasket & intake gaskets. See which area sucks in the oil and causes the manifold vacuum to rise….

When you measured the pressure was the pump dead headed or did you hook it up so that the fuel went from the pump to the gauge then to the carb? The latter set up is the better way to check fuel pressure so you can get an accurate reading of actual fuel pressure with the engine running. I tested...

What do the center electrodes insulators look like on the spark plugs, black?= rich, white?= lean, tan/grey?= about right. Quadrajet carb….are the idle air tubes clean? Float height? Excessive primary throttle shaft play? That can def cause a vacuum leak. You can check it with the throttle cable...

How about an intake gasket leak either under the carb or one of the actual intake gaskets & maybe an intake valve not seating fully?

You certainly can do that, but keep in mind that you'll probably see mostly Vortec heads that won't work with the pre-Vortec intake manifold. And, I'd still take anything I was going install into an engine I wanted to be reliable to a machine shop to get magnafluxed.

If it's shifting into gear and staying in gear like it should but it stalls when coming out of gear, it could be nothing more than carb adjustment/engine tune. The OMC ESA system is a good system but it requires an engine in good enough tune to run at 600 in gear and 450 momentarily. Also...

https://www.ebay.com/itm/800044960560?_skw=OMC+CObra+tools&itmmeta=01M37AY15A7EDKJZHWS4D0JVQK&hash=itemba46654b30:g:QGsAAeSwtyNogBGa&itmprp=enc%3AAQALAAAA0GfYFPkwiKCW4ZNSs2u11xCUt0UC8fBTTu2f%2FDVbKXHdcoVOjhd%2BSDxeO9W6rcr4yvbLWjelSQDtorcMlLK2gSeOBuii4jP01uEuqda7EKLMmUloD3t3%2BIHIfnJ0H1iqZ2NtW%2FN...

I went back and looked at my Blackstone Labs result on my Cobra drive from 2015. Iron was 369 ppm water was zero. This was based on one season & I’ve always changed the oil at the end of each season. So depending on how long of a run those drives had on the same oil, it may or not be a problem...

The lines inside the valve port could be casting ridges but the one going in between the intake & exhaust valve seat areas looks like a crack, that’s how mine were in the center cylinder of each head.

There are also special tools you can buy that make the set up more accurate.

https://www.marineengine.com/parts/omc-parts/omc-boat-parts.php?year=1993&hp=5.0 It's probably one of the first three in this list....the others have efi.....

PS the model # is usually on the engine, a light grey sticker on either the valve cover or the thermostat housing. While your boat may be a 94 the engine/drive package must be a 93 because the 94 and up drives were totally different, that was the joint venture drive made with Volvo, and is the...

Ok I have had one of these for over 20 years and have done the adjustments myself, mine is a bit different, but I'll try to cover the basics first: first thing, the Cobra shift cable should not have more than 2.5 lbs of drag in either direction, with it disconnected at both ends, more than that...

Sure looks like it. Since one shutter is missing, they don't just disappear, they get melted from an overheat, does the other one look melted, or OK? If melted that suggests it's overheat damage.... One of mine was vaporized, (landed in the bottom of the Y pipe) the other got melted, I had to...