Gmc 270 engine

[SCHRUMGMC]

Where can I buy engine parts such as pistons, valves, piston rings.

What is the best carb to use for this engine? I am currently running a Rochester C 1 barrel

I'd like to find another intake manifold for my 270 as well, I've seen that they make a 4 barrel one.

[whitedog76]

Try Patrick's for rebuild parts

http://www.patricksantiquecars.com/chevy_parts.html

Clifford for 4 bbl manifold

http://cliffordperformance.net/Merch...gory_Code=C250

[OrrieG]

http://www.inliners.org/ would be a good site for you to spend some time on, especially if you want to start adding hi-po parts to the 270. You are going to find that it is very expensive to rebuild these, but knowing the history of the truck you want to keep the engine. I have the same issue with my Chevelle number matching 283, I bought another complete short block that had all ready been over bored because the price was cheaper than buying the .30 over pistons.

[SCHRUMGMC]

I can't find anything on that site, perhaps I am not looking hard enough

The truck still won't run right though

[tmoble]

what's the complaint about the way it runs?

I built a 302 Jimmy awhile back, had a bunch of parts from Patrick, manifold for Holley with Holley 600CFM, some kind of split exhaust manifolds with 2" duals. Rigged up an HEI, tuned the carb abd dist setup, ran pretty good. killer Tq down low, ran out of air pretty early. IIRC, the head was bowl ported with nice comp style 3 angle valve job. Again, IIRC, it was .060 over.

I had to rebuild my engine stand, I thought the dang thing was going to break the head off it. Took 2 guys to set the head on. Freakishly heavy.

It was in a 53 Chevy coupe, 2" straight pipes out the rear bumper. Sounded like it was going to tear a hole in the atmosphere. fun car to drive around.

[dwcsr]

http://egge.com/kit/gm270m56-62/

if they don't have it they can make it.

Clifford make a manifold for the 270

[fourspeedwagon]

Originally Posted by SCHRUMGMC

I can't find anything on that site, perhaps I am not looking hard enough

The truck still won't run right though

click on "our products" then click "1937-1962 chevy/gmc engine rebuild parts" then scroll down past the chevy stuff and transmission stuff and you'll find the gmc rebuild pieces. Not the greatest put together website but I found it---

[SCHRUMGMC]

Heck, I didn't even find that lol. I just can't help but wonder what is exactly wrong with my truck

[fourspeedwagon]

Well, how about a rundown of what's going on with it? There's some smart folks on here (as I'm sure you know).


I'd think that to run a 4 barrel you'd need quite a few other modifications before all that carb would be needed. Closer to stock maybe a good 2 barrel like a 2GC?

[SCHRUMGMC]

I have all new ignition parts replaced in the last year, carbs been rebuilt but it leaks around the linkage and the front brass hole thing. I still think the timing is off a little

It will only run with a choke at times, still think its timing.

[tmoble]

Do you have a timing light?

The throttle shaft and bushing do not contain fuel and can't leak. If the fuel leaking from the shaft it's running down from above. usually find out there dirt or something in the needle/seat, leaky float, too high float level. some along that line is letting the carb overfill, then it drips or runs out of the booster venturiis and leaks out the end of the shaft.

Always and forever, get the timing/other ignition issues worked out, then start fiddling with the carb.

[SCHRUMGMC]

Thanks, I wonder why people say their throttle shaft is worn out?

I may just need a new float

[tmoble]

yes. The shafts can be worn, but this doesn't make the carb start running over. Also, I've discovered the hard way that if something is making the float bowl run over it'll leak out of new throttle shafts too. hot gasoline is very thin.

fix the real problem, it'll stop "leaking" from the shaft. get a carb kit and a float. Make sure there's a good fuel filter in the line. I use the metal can filters, simple cheap. Don't care for those glass ones with the strainer in them.

Do you know which carb you have?

[SCHRUMGMC]

What is the best carb for a 270?
I keep hearing that a Rochester B, will and is nothing but problems. I like mine but it causes problems like leaking

I am thinking about buying a Zenith, the original carb for the truck

[tmoble]

That looks like the original carb, unless it's different for GMC.

I've used lots and lots of those carbs over the years, including a couple Trips setups. If you're having repeated problems maybe you need to farm out the re-build. Are you DIYing it?

I'm not sure what the Zenith carb is, got a link or pic?

I can fix that carb for you if you want. PM me if you want to discuss.

[SCHRUMGMC]

https://www.youtube.com/watch?v=3u8x9xTwXD0

The GMC's 270 originally came with a Zenith, from what I've been told. The Chevy's came with Rochesters

Thanks for the offer man, I sent it to a older gentleman by the name of Roy in Texas and he fixed it but it still causes problems. Its been like this for the last 20 years. Another reason it wouldn't run for my Pawpaw and he parked it. That is the only thing I can think of

[SCHRUMGMC]

Where can I buy a Zenith 1 barrel carburetor for my 270?

[fourspeedwagon]

there was a guy posting rebuilt zeniths on the oldgmctrucks site.

[SCHRUMGMC]

What is the model of the Zenith for the 270

[OrrieG]

http://chevy.oldcarmanualproject.com...559mm0i09.html

[fourspeedwagon]

zenith 11147 but 11475 and 14475 are the slightly newer replacements. Any of these are good for your 270.

[SCHRUMGMC]

I need to find a place that sells them

My Rochester is nothing but problems

[fourspeedwagon]

http://www.zenithfuelsystems.com/dea...#northcarolina

They still make them- the one you need is model 228

[tmoble]

do you drive on extremely rough roads? sometimes this will cause issues with the carb flooding over.

I've worked on/fixed somewhere between dozens and hundreds of those carbs, no problems. I used to have access to a 50's 6 cylinder, I rebuilt the carbs and tested on that engine if they reported as a problem child like the one you're describing. Never had one I couldn't fix. I'll bet it has a bad float.

There's no good reason why that carb should have these issues. PM me if you want it fixed.

Have you looked down in the carb with a flashlight after running the truck and getting good and hot? See it boiling over?

Does you engine have the heat butterfly that directs the exhaust to a hotspot uder the carb? I've seen trucks where that butterfly was stuck, overheating the carb all the time. That'll cause the same problem with a Zenith too.

[SCHRUMGMC]

I highly doubt you could fix this carb man

Where would the butterfly be?
I'll pm you my number