Identifying 1976 Engine-is it a 302 or a 351?

[orttauq]

Just bought 1976 American Boat Company Eagle 18 foot and need assistance in identifying the engine size. It is a Ford small block that has been modified over the years. It has an Edlebrock manifold that I am sure is not a marine one as well as a 4bbl carb (no idea on make). These boats came with 2bbl from what I have been told. I have read up on all the info here to find the engine tag but it is not in the noted location(s) for a Ford (rear top of block, near head) nor near the starter. I know that 351s have more manifold bolts than a 302 but with this aftermarket intake manifold I can't really go by that. The Mercruiser outdrive has 888 decals BUT the serial number (4228535) does match up as a 233. I did find some numbers in the block right above the starter...would these help?

Thanks

 

[Bt Doctur]

measure the spread of the intaks bolts around 8.5 is 302 and around 9.5 is the 351

 

[orttauq]

measure the spread of the intaks bolts around 8.5 is 302 and around 9.5 is the 351

THANKS! Looks like a 351

 

[Scott06]

THANKS! Looks like a 351
View attachment 369667

yes the deck is taller on a 351 hence the wider intake bolt spacing

Take a picture of the carb, thinking it is an old Carter AFB given the sticker and the fuel inlet location. I would verify it is a marine carb not an auto one... Not sure if the Old carter AFBs (that sticker predates carter selling to federal mogul (late 80's early 90's?), which predated webber making them, which predated Edlebrock taking over the design....

I think this would have had a Holley or Rochester 2 bbl when merc made it but that was before my time

 

[Scott Danforth]

that is definitely an automotive carb. you can see the vac lines plugged

 

[Scott06]

that is definitely an automotive carb. you can see the vac lines plugged

That's what I was thinking too. Somebody was short a vacuum cup assortment ...

 

[orttauq]

As requested:

 

[orttauq]

Yes, It is a hot mess; choke not wired up, all the vac lines plugged with bolts, I am sure that the 4bbl part is not working. I have a winter of work ahead of me but as for the carb it will just be replaced with correct one which requires me finding the right intake.
Thanks

 

[kenny nunez]

If the manifold is a dual plane style it should work out with no problem.
Summit Edelbrock #EDL-1409. 600 cfm @ $573.95.
I am sending you a private message.

 

[orttauq]

Right but I read somewhere that a 4bbl is useless w/o the right cam and heads (valves). These motors turn 4k WOT so it is not like I am going to get more top end RPMs no?
How would I determine if manifold is dual plane?

 

[Scott06]

I think yours is a a dual plane - likely an Edlebrock Performer.

That is not a marine carb. as outlined about would swap it for a Edlebrock 1409. Yes all stock marine cams are fairly sedate in terms of duration and overlap, but usually there was a 15-30 hp diff between 2 bbl and 4 bbl versions of engines back in the day. 1409 is used on 4.3- 5.7 l engines so should be ok for your application

 

[Eric 3.7LX Alpha 1]

That flame arrestor looks like it needs a good cleaning too.

 

[Scott Danforth]

Right but I read somewhere that a 4bbl is useless w/o the right cam and heads (valves). These motors turn 4k WOT so it is not like I am going to get more top end RPMs no?
How would I determine if manifold is dual plane?

I read on the internet that I am a french model.

bonjour

these motors will spin to 4400 RPM and beyond

that carb is not a marine carb and I would replace it or risk

 

[orttauq]

...that carb is not a marine carb and I would replace it or risk

Yep, the whole reason for this post; determine the engine to find the right OE intake to get the right carb back on the boat.

Found this locally but a no go for my motor; https://spokane.craigslist.org/bpo/d/oldtown-intake-manifold-and-carburetor/7529242588.html

 

[Scott06]

Yep, the whole reason for this post; determine the engine to find the right OE intake to get the right carb back on the boat.

Found this locally but a no go for my motor; https://spokane.craigslist.org/bpo/d/oldtown-intake-manifold-and-carburetor/7529242588.html

intake is fine if it is dual plane, which it looked like in photo in post #7 you can see the runners are on two different planes, so it is actually an upgrade as long as you are in fresh water. Salt or brackish will rot a non marine aluminum intake.
just get a marine carb and you are good to go. Eddy 1409 s work very well out of the box.
only thing is if some one replaced the cam with a automotive cam , but if it idles smooth you are likely ok

this is a thread discussing hp ratings on the 351 https://forums.iboats.com/threads/1975-mercruiser-233-drive-351-ford-any-good.645741/

 

[orttauq]

intake is fine if it is dual plane, which it looked like in photo in post #7 you can see the runners are on two different planes, so it is actually an upgrade as long as you are in fresh water. Salt or brackish will rot a non marine aluminum intake.
just get a marine carb and you are good to go. Eddy 1409 s work very well out of the box.
only thing is if some one replaced the cam with a automotive cam , but if it idles smooth you are likely ok

this is a thread discussing hp ratings on the 351 https://forums.iboats.com/threads/1975-mercruiser-233-drive-351-ford-any-good.645741/

Thanks for the info; yes, fresh water only.

 

[ddrieck]

What's with the bailing wire?
Holding the choke full open?

 

[orttauq]

What's with the bailing wire?
Holding the choke full open?
View attachment 369888

Good eye. I will have to see; boat is at the lake but will see when I get back up there. I had noticed that the elecs had been pulled from the choke. Based on what I have been told here I have the correct carb on its way so not really worried....

 

[tango13]

Is this boat a red/white/blue American? I’ve seen a few of your posts and from what I’ve read, it sounds like one I looked at about 8 years ago. I used to own a ‘78, they are great boats.

 

[orttauq]

Mine is green and white. I bought it in Montana but then found out it spent most of its life on Priest Lake, where I have it now.