I prefer the Edelbrock after working on so many on boats but... I think the Holley will be the better fit on a stock 312. Boats don't usually have all the carb tuning issues that we have on cars but the smaller Holley should still be easier to set up for the 312 and you may be able to get a little better milage out of it, never hurts as boats get notoriously bad milage.

1956 Fairlane Victoria (ORREO)

 

Overlooking Beautiful Rimrock AZ

So my carb choices so far are either the Holley marine 450 or 600 or the Edelbrock marine 600. I need some opinions. I can get the Edelbrock for almost half the price.

that picture brings back memories. i had a 1956 richards 23' open boat that looked almost the same. i put a 850 holley double pumper on that 312. it was a little over fueled but it was the best sounding boat at the dock. it ran great. a 600 cfm would not be too big as long as you jet it right. remember you're under a load most of the time. always use a spark arester.

 lincoln/merc. y-blocks &mel's                                                               bucyrus, ohio.

Look on the back and front ends of the alternator, if there is screen over the vent openings it is a marine unit. Starter also needs to be marine, this usually consists of sealing any openings to the inside of the starter such as gaskets under cover bands. The Holly carb was used on many older 302 Fords and should work fine, they are available as a reman. Don't forget you will also need a flame arrestor to go with the carb. Marine distributors do have a gasket under the cap but they also need to be vented. Some have a screened vent in the side but I have also seen some with a 90 degree elbow installed in the side with the opening pointed down. I haven't looked but would assume there is some form of screening in the elbow.

1956 Fairlane Victoria (ORREO)

 

Overlooking Beautiful Rimrock AZ

I will make sure to look at the distributor and alternator when I get it home. The boat is stuck at the current location until the snow melts. I will also look into rebuild kits for the carbs. The prior owner got so fed up with the carbs, that he bought a newer OMC 350 to replace the 312. Luckily he never got around to installing the 350. The engine not starting consistently was the main issue he had with the engine. So it might be more than the carbs.

Someone recommended that I install a Pertronix Ignitor in the distributor. Would this be a good idea?

From what I have to been told I’m the fourth owner of the boat (1959 22’ Chris Craft Sea Skiff) and the motor is stock and has not been rebuilt. Overall the boat is in great shape and I can’t wait to start working on it.

The distributor is probably a Mallory single or dual point without vacume advance. There should be a rubber seal ring under the cap. I picked up two of these a few years back and got a lot of good parts from them. Most boat motors don't have a lot of running time on them. From the picture that motor looks either repainted or really fresh.. Could be a real score. Is there by any chance a rebuild tag on the side of the block? 

The carbs are the same at the Vette Blue Flame 6cyl from 54/55. Check on the scrub sites for rebuild kits. They are one barrels and work very well for the boat application. I wouldn't worry about them. They should have spark arresters on each of them. Usually a small brass air cleaner type assembly that mounts on the valley cover and carbs. I don't see them on this engine but someone out here probably has some. It's hard to tell without opening the engine what size it is. My last ones were a 292 and a 312 mounted side by side. One was a reverse rotation engine. Thats normally done in twin engine rigs. Easy to tell the rotation by pulling the front cover. If it has a timing chain its normal, if a gear drive its reverse. Chuck in NH

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

I had a Holley marine carb on my previously installed OMG 460 King Kobra.... I believe it was a 600 or a 650.



I think a 450 on a 312 would work just fine.



That alternator doesn't look like a marine unit. (It may be) Make sure you have a mechanical advance distributor. Vacuum advance is not normally used in marine applications. You'll want to also ensure that the dist is completely sealed.



I don't think there was an SAE J1171 spec back when that engine was new.....

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1955 F-600/272/E4OD// Disclaimer: No animals were injured while test driving my F-600 except the ones I ran over intentionally!

---------------------
This post was created using OpenSuSE Linux x64 and Firefox

I officially purchased the boat today. The engine is in an enclosed space, and I'm guessing (and hoping) all the parts are marine grade. The boat is in storage until the weather gets a little nicer.

I would like to start buying parts now. I have found a few used ECZ 9425 B intake manifolds, and I'm still researching what carb I should get. The holly marine 450 cfm http://www.holley.com/0-80364.asp is my top choice so far. What do you think? It's designed for a 302, will it fit and work? The Holly is pricey, so if anybody has another choice let me know. The Edelbrock marine 600 cfm is cheaper but it sounds like it might be a little much for a stock engine.

Howdy,



You can easily use the Holley Marine carb of your choice on that engine. The 450 should work fine for a stock engine.



This is an enclosed engine compartment isn't it? Make sure that you're using a marine type fuel pump and that it has an electrically sealed alternator, distributor, and starter.



If you're using a mechanical fuel pump, does it have a clear hose running from the pump body to the carb? (if not, you run the risk of Kaboom!) The hose is to alert you to a leaking fuel pump diaphragm.



You can probably put that marine manifold and side-draft carbs on ebay and sell them too.



Pictures!!





Regards,





Rick


-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1955 F-600/272/E4OD// Disclaimer: No animals were injured while test driving my F-600 except the ones I ran over intentionally!

---------------------
This post was created using OpenSuSE Linux x64 and Firefox

I’m in the process of buying a boat with a 312 interceptor with dual side draft Carter carbs. The past owner had trouble with the carbs and couldn't get them to run correctly. I would like to rebuild the carbs or replace the intake with a 4 bbl intake with a modern marine carb. It seems that the stock intake with the side draft carbs can be a fire hazard and are difficult to adjust. If I were to buy an ECZ 9425 B intake what size or brand of carburetor should I buy? I would like to buy a new marine Holley or Edelbrock with an electronic choke. How many CFMs would be adequate for a stock marine 312? Is 600 too much? Holly sells a 450 cfm marine 4 bbl. What modifications would I have to do to get the intake to fit and run? I do understand I might have to add height to the engine box. Thanks for your time.