VCCA Home Forums GENERAL DISCUSSION General Discussions wondering ...the start of life for my spare 235 built in 1958

So I have this 235 motor and it has a cast date of B=Feb, 5=day, 8=58 and the stamp date is F=Flint, 2=Feb, 7= day and what I thought was an 8 but turns out to be a B= hydromatic which seem to only be used in cars. Stamped only two days after it was cast got me to wondering about the process from cast to assembly. I started Googling to see where it might have been cast at and came across a list of GM plants. There was a foundry in Saginaw Mi. which isn't far from Flint, called Saginaw Malleable Iron also stated Iron castings HQ of Central Foundry Division, opened in 1919 closed in 2007. So that's my guess, cast on the fifth sent over to the Flint assembly plant and stamped on the seventh. The closest thing to an assembly plant on the list of GM plants in Flint was called Buick City. Any way just killing time on a dreary day. For working at GM in the Detroit area for about 20 years I sure don't know much about their operations. Heck I don't even know where we got the blocks for the Cadillac's I helped make.

Hydramatic was used i trucks only. Cars had Power Glide.

what is the stamped engine number.

F207B

That would be from a passenger car with Power Glide.
Engine would be the same for a standard trans. car except for the carburetor and flywheel.

Do you know the difference in the carb and flywheel? I thought it pretty cool only two days difference between cast date and stamped date. This spare motor was just block and complete head which was made four years later but correct for the motor. I found a bunch of parts from another 235 that I bought, a flywheel, bell housing, clutch disc, pressure plate, valve cover, two starters and a head complete with valves and springs. I'm pretty sure they were all off of a 1955 car and without going out to look I think the head last three #'s were 913. My plan was to use these parts on the 1958 motor when I replace the 216 in my 47 Aerosedan ,

Don't want to be nit-picky, but if I recall correctly, I saw a 1956 Chevrolet police car brochure that stated cars with this option got a hydramatic transmission. Was very surprised to read that and made a mental note to remember it.

From another site: Head number 3835913 is for '53-'55 235's. Head number 3836848 is for '56 and up. The "848" is a much more desirable head, for what it's worth!

The 913 head and 848 head are the same except for the casting changes for the valve cover attaching screws on the 848
The 848 head camw with three differnt comprssion RTIOS RANGING FROM 7.5 TO1 TO 8.25. THIS ID NOT REQUIRE CHANGING THE CASTING.

So Gene, the compression ratio for the 913 and 848 heads were the same and could be 7.5 to 8.25-1 ratio? Is there a way to tell the ratio by looking at them? I was glad to find the 848 head because I was told it would have the highest ratio available. If the two are the same heads and both could be any of three different ratios then I will just use the one with the highest ratio if there is a way to tell. Thanks

As Gene posted on Chat January 2011:" The 848 head came on the 1956-1962 engine. The head started with a 8.00 to 1 compression ratio in 1956, raised to 8.25 in 1957. Is the same as an earlier (1953-1955) head except for the method of attaching the temperature sender and the older ones having a 7.50 to 1 compression ratio." I am curious what the temp sender difference is and what needs to be done when changing to the 848 head.

Ok, Thanks. I didn't see his post from Jan. 2011 but I understand now, the 913 head is basically the same as the 848 but 7.50-1, the first 848 in 56 was 8-1 and 57-62 ratio was 8.25-1. I'll plan on using the 1962 848 head and have the 1955 913 for spare or sell.

Chevrolet sold the 848 head for replacement on 1953-1955 models.sold an adaptor for the temp. gauge.If Power Glide engine isinstalled in a stick car a pilot bearing must be installed in the back of the crank shaft.

NO CHEVROLET PASSENGER CAR WAS EVER SOLD WITH A 4 SPEED HYDRAMATIC TRANSMISSION.

Gene, check your PMs.

The compression ratio will be determined by the size of the combustion chamber in the head, larger chamber lower comp ratio. I dont know the calculations but measure the size of the chamber and use that as the final volume then you need the volume of the cylinder with the piston at the bottom of its travel.
Tony