The Stovebolt Site Forums The Parking Lot Big Bolts 235 six or not?

I want to know how to determine what size six cyl engine my truck has in it. It is a 1956 Chevy 6500 with a six cylinder motor. I want to determine if it is original and what size it is. The data plate gives a GVW of 16,000 lbs. and lists the horsepower ratings for both the 235 and the 261. What numbers do I need to look for to find the size and the year? Thanks for the help.

Find the 7 digit block casting number then go to www.inliners.org casting numbers page and look it up.

I don't know how it works with the later models, but in the '40's and early '50's models, all you really need is the letter prefix off the engine serial number, then check it against the page that cletis linked to.

Do you have any Captain's bars over the starter? I you do, then it's a 261. If you don't, odds are it's a 235, but not a certainty. Then it's back to the numbers.

from truckedup:
"58-62 261's used in trucks have 1/2 inch pipe thread oil ports on the left [driver] side, no 235 has these"

Bill

The serial numbers from '54-'56 are different than the '40s and early '50s numbers (and '57-up changed again). Look for the engine serial number stamped on the pad to the rear of the distributor. If it's a '56 engine, you can check the suffix on this page.

Let me get out and see what numbers I have. I think it might be original because the truck is relatively low mileage and the engine appears to be the original yellow color without any sign of anything being disturbed. It was built in Atlanta according to the VIN and has spent it's entire time about 40 miles away until I took it to South Carolina. I bought it from the son of the original owner but he was'nt sure what size the engine was. The truck sat in a shed type building for years and hasn't been registered since the mid seventies. I am the first person to ever title it because Georgia didn't title autos in the 50's. It has power brakes I think but the master cylinder and booster are separate from each other. The vacuum line runs to the intake and the brake line appears to leave the master cyl and run into a small part behind the booster then to the wheel cylinders. It also has a vacuum operated 2 speed rear axle. I'm more familiar with late sixties and seventies Chevy's with V8's but the truck is fascinating and I'm getting a real education on this site. There will be a lot more questions about things as I go through the different parts of the truck. I do appreciate all of the advice and help.

If the engine paint is original and it's Yellow, then it should be the 261. The 235's were gray.

Mike

I'm glad now! I checked the numbers like you said and it is a 261. The number was 3837012 and according to the list it was 1955-1957 so that covers mine. Now I need some parts. I'd like to find a correct original oil bath air cleaner. Does anyone have a picture of the correct one?

I have a picture that red58 sent to me. I'll see if anyone has any parts for sale.