347 Pontiac???

I just got a Pontiac, its a 57 with a 347 in it. This is a first for me, never owned a Pontiac before, Apart from having a few chevy engines, first time I bought a car without a blue oval on it.

Is the 347 a decent engine or ? What about hop up stuff? was there much stuff made?

Any inherent problems with them that I should look out for?

 

347 is a great engine; a friend of mine up the road has one in his 57 2 dr hdtp with three deuces. I'll ask him about inherent problems, since he has two 57 Pontiacs.

 

There are still Offenhauser and Edelbrock intakes for the '55-'60 bolt pattern floating around at swap meets, and the camshaft stayed the same design forever, so cams are no problem; however, you won't find headers to fit '57 heads.

 

The Pontiac V-8 has the greatest interchange of any V-8 engine ( inclu chev).
It is a good motor though small. Many of them have forged cranks too.
If your main bearing are decent, save them to re use as new ones can be pricey. You can bolt any Pontiac head to that block, then use any intake that fits the heads. simple, simple.

Steve

12th annual Pontiac Heaven coming back to Phoenix in 2010
www.pontiacheaven.org
8th annual Nostalgic Show and Go! coming back to Phoenix in 2010 www.nostalgicshowandgo.org

 

I had a 57 Pontiac a few years ago that still had the original 347. It had never been rebuilt or anything and it still ran GREAT. Did not smoke, knock or anything, fired right up and purred like a kitten. The only bad thing about it was that it had an exhaust leak and the fact that it was a midwest car, the bolts were so rusty that I could not get them out to fix it. I drove the car for a couple years with no problem. I sold it a couple years ago when we were trying to sell our house to buy a bigger place but the market went in the dumper and my house did not sell and now I don't have the Pontiac. So, we sold it for nothing. Cool car.....post some pics of yours.

 

One of the guys that I worked with back in the late 60s raced circle track running a 347. He preferred it over the more plentiful 389 engines probably because of the shorter stroke.

 

Thanks for the advice. The car is a Safari, I just picked it up from the docks today. It is the one Sled was sellling here on the HAMB. Will post up some pics over the weekend.

 

Not true. At the Norwich swap meet a couple years ago I bought some Pontiac headers off a guy who was selling everything cheap, took them down a few spots to some guys who had all sorts of pieces from parting out a '57, I set the flange from one to the ports of one of the heads they had laying there, and they matched up perfectly. Bolt on. I think the only real difference is 55-56 have smaller ports, but the '57-up have the usual D-ports.

The problem in a '57 is there is very little room between the starter and the steering box, the stock manifold dumps at the front in fact because of that. You can sometimes work around it, especially if you convert to a Saginaw 605 steering box and slip some U-joints in your column, but guys have managed to fit center or rear dump manifolds into these.


'57 I believe is one year only main bearings, possibly rod bearings, would have to get the book out to be sure. But they're a good reliable torquey motor, heck they ran 140 mph at Daytona Beach in the speed trials when they were new, as fast as the Chrysler 300s. Most of your direct interchange is 55-60, the transmission adaptability is real limited short a 58-60 manual bell (which lets you run most any newer manual trans) about all that bolts up is the early hydramatics. If the Hydro works good, don't abuse it and it should last a long time, they were a good design.

 

Pontiacs....can't beat the old engines....I race the piss outta then......389 and 421's are my favorites......ask Nuncie in NYC!!!!!

 

You had to mention Safari.......Now I am slobbering all over the keyboard.

 

The 57 Pontiacs have holes from the outside of the head (has a little "doughnut" around it) that goes directly to the exhaust valve stems. No filtration of the air sucked into the valve guides. There was a factory fix consisting of lead plugs to pound into the holes. Something to keep in mind if you wind up tearing into the heads.

 

Question regarding the round center ports on the 347 manifold and the little tube that runs through there. What is the port's purpose? Is it a water jacket? I'm baffled. I ask because I recently picked up a nice 58 manifold but the little tube that runs through that center port is cracked.

Decided to resurrect this old thread after it surface in a Google search: I've a freshly built 347 in my 57 Catalina before the previous parked it for a few decades. The motor was a former tri-power but after the rebuild they stuck a '56 manifold and 4GC on it. I'm wanting to upgrade the manifold to 57-59 style to use a Carter AFB.

 

Sounds like the heat tube for the automatic choke. Outside air was drawn in thru the tube, heated in the manifold and plumbed to the choke thermostat housing. If you're not running the hot-air style automatic choke you can remove the heat tube and tap and plug the holes in the manifold. You might also be able to find an electrically heated choke thermostat to replace the hot-air version and also eliminate the heat tube.

 

If you want to keep the stock choke setup, replacing that little tube in the manifold is not that hard to replace. Need to remove the manifold to do it obviously.

 

That port provides a path for exhaust heat to warm the base of the carburetor for better cold weather performance. One exhaust manifold has a Heat Riser Valve that (when working properly) closes up when cold and slowly opens as the engine warms up. When the engine is cold, and the valve is closed, the exhaust gasses pass from the closed off exhaust manifold, through the passage under the carburetor to the open exhaust manifold and out the exhaust system. The little tube provides warm air to the choke housing to actuate the thermal spring that slowly opens the choke.
As someone noted, that little tube can be knocked out and replaced or knocked out and the holes tapped and plugged if your new carburetor has an electric choke.

 

Thanks! Bob. Those were the technical details I was looking for. The flapper valve in the 347 does work but I converted the choke to electric so I won't need that setup. Looks like I'll work on removing that tube and plugging the holes sometime over the winter.

I should add, before I found this Poncho, I was mainly a Mopar guy so these GM setups are foreign to me. LOL.

 

Thanks! I did convert the choke on my current 4GC to electric and will stick with that setup when I swap manifolds so the choke heater won't be needed.