The Stovebolt Site Forums The Parking Lot Big Bolts 1956 GMC LCF motor

My '56 GMC 350 lcf motor is stuck. I'm trying to find out what motor I actually have 270 or 302 and is it one worth rebuilding ? I looked for the #'s and I found
these : GMC4 2135412
Can someone tell me what I have ? Thanks in advance.

Where did you find that code on the engine.

On GMC 6-cylinder engines, the engine size is usually pressed into the block as part of the engine serial number code (to the rear of where the distributor goes into the block).

1946-1954 270

Those #'s are on the intake side of the motor.
So would this be a good candidate for a rebuild or is this one of those early ones that is a splash oiling.

I don't think any of the GMC engines were splash oilers but even if they were that would not make it a bad engine. A zillion Chevies ran and still run that way and give great service. I really don't understand the widespread and I beleive misunderstood bias against those engines. They were every bit as good as the flathead F*%ds and Chrysler engines of the day. And now everyone seems to want a flathead V8.

Have you looked on the backside of the glovebox lid? My 57 GMC 370 LCF has all kinds of info on a tag riveted on the lid. It tells me mine is a 270 engine, cab 1762,Tranny GM type SM420 4speed and lots of other stuff including rear end,spring leaves, ectra. I have found out that GMC numbers are nothing like Chevy.
Wayne.

It is best to use codes on the engine to ID it.
Engines get swapped.

The 270 is an excellent engine. It is a full-pressure/high-pressure engine.

However, even the 216 and early 235 engines with babbetted rods and dippers were not really a splash oil engine.

Thanks for all of the input. I'm definetly going to rebuild it.

So did you figure out what you have based on the stamped serial number? Do tell...

Mike B

The numbers on the block come up 46-54 270.

I thought all the lcf's came with V8 engines?

GMC's are not really called LCF by GM. That designation was for Chevy's. GMC's were called Short Conventionals in the sales brochures.. And yes they came with 6 cyl. 270, 302 and another 6 I can't remember. Also v-8 engines. A lot of the engines were Pontiac, mine says Pontiac in the glove box.

A 350 would have been born with a 270 if its a 6 cylinder. The Pontiac in the glove box refers to Pontiac MI. It was the 400 series that got the 302 engines. However, as Tim said, almost anything from a 228 up to a 302 could have been installed because they all bolt in. Scrape the flat part of the distributor boss and see if it looks like it is factory machined. If so, The first 3 numbers will be the displacement.

LCF's came w/ 302's, had one, hard to remove, look by the starter, on a machined pad, right side of engine, SN starts w/ displacement, i.e. 302xxxxx. What trans do you have? All 228, 236, 248, 256, 270, 302, were, from the start, full pressure oiling, starting in '38 when that engine was introduced. Good oil sys. mod tips for full flow oil filter, etc., avail.

My GMC LCF 370 w/270 engine, has a big curved pipe and hose attached to the carb and the oil bath breather is off to the side mounted on a bracket.
Is this the original setup?
Thanks.

Did the Chevrolet LCF's just come with V8's?

Yes