Some 235’s have the oil filler cap in the middle and some have them up front. What years had which? I’m thinking this might be a general way to differentiate whether you are looking at an old motor or a newer version motor if you can’t see or get to the casting number easily..
Chuck 1950 Chevy 1/2 ton (all original) 1951 Chevy 1/2 ton (future streetrod) 1941 Chevy coupe 1938 Chevy coupe streetrod
my ability to distinguish them at all completely fails and I rely on casting numbers
Old 235 is A dipper like a 216 and has 2 bolts on top like a 216 at least that’s what I’ve been told, not sure I have ever see this engine in person, it should have a filler at the front
Then there is a 1-2 years of a First full pressure 235 that still has two bolt ontop valve cover like 216 with filler that front I have about 4 of these engines and it’s a work horse, it’s the default engine in all Canadian 1953 Chevy and gmc products except the big 3 ton gmc which got an actual gmc engine
Someone should make a comprehensive identification guide hint hint -s
The oil fill cap position has more to do with the type of air filter the negine was originally equipped with than any magic wand to identify the engine, plus the valve covers will swap on any engine with the 4 valve cover screws around the perimeter. Casting numbers are hard to swap unless somebody is really good with a cutoff wheel and a welder! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
This might be what you are looking for. As earlier posted, valve covers can be easily switched, however I would consider them as a quick indicator until I checked the block numbers.
"general way to differentiate whether you are looking at an old motor or a newer version motor"
Yes but in the case of picture #1 there is a 59-62 valve cover on an engine that has the older Carter W1 carburetor and also the horn mounted to the intake manifold. This tells me that the exact year of engine manufacture is suspect. The engine could have had a dented valve cover and a previous owner swapped it out. The engine serial number, block & head casting dates and numbers are better identifiers if you are seriously wanting to determine the year(s).
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
"This tells me that the exact year of engine manufacture is suspect. The engine could have had a dented valve cover and a previous owner swapped it out."
Maybe so, but the newer version valve cover would need four attachment screw holes drilled into an older head?
"The engine serial number, block & head casting dates and numbers are better identifiers if you are seriously wanting to determine the year(s)."
“The 1954-62 valve covers with oil fill in the center are for cars, oil fill in front is found on trucks.”
That’s similar to what Jerry said above. I *do* know the air filter is substantially larger in a car vs a truck, so GM probably had to move the filler cap to get out from under it.
RdsLessTaken, thanks for posting the pic of various valve covers. I’ve seen it before but forgot about it.
Chuck 1950 Chevy 1/2 ton (all original) 1951 Chevy 1/2 ton (future streetrod) 1941 Chevy coupe 1938 Chevy coupe streetrod
"Maybe so, but the newer version valve cover would need four attachment screw holes drilled into an older head?"
Tim, you and I are 180 degrees out. I was thinking, why an older W1 carburetor and maybe older intake on an newer 235 engine?
Paul, I would appreciate it if you can provide a reference on the "car only" center oil fill information. The reason I ask is more for curiosity. Most likely the design change was due to lower profile hood design for 1959 cars with 235 engines. I've read postings at other websites that SOME 1959-62 "era" trucks with 235 engines came out new with center fill position valve covers. Maybe GM simply got rid of old inventory valve covers by installing them on new trucks. Maybe when the supply of front fill valve covers was low enough, they simply switched over to the center fill for trucks.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
Tim, you and I are 180 degrees out. I was thinking, why an older W1 carburetor and maybe older intake on an newer 235 engine?
The older 216 parts bolt right on to the newer 235, so someone had a bad engine, bought a new long block and swapped all of the old bolt-on parts onto it...done all the time!
Mike B
Mike Boteler
1956 Chevy 3100 Resto Rod 1952 Willys M38 Army Jeep 1983 Jeep CJ7 Laredo 1984 Jeep CJ7 +++++ Silver Spring, MD
Odd ball me, running an old style 216 valve cover on my 261! All you need to do is remove two rocker shaft bolts and replace with 'STUDS' from 216. But that's really not the issue here, as stated engine serial number and cast numbers tell the true story.
Even with the 2 bolt valve cover, Ray Charles could figure out that there's a late model engine in a pre-54 truck. I'm getting pretty close to putting my 258 cubic inch "216" together, one that looks original from the outside. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Would someone please explain to me why the 1954 cover has vents and the later covers do not. What would happen if you ran the '54 vented cover on a later engine? What would happen if you ran the non-vented cover on the '54 engine?
"The older 216 parts bolt right on to the newer 235, so someone had a bad engine, bought a new long block and swapped all of the old bolt-on parts onto it...done all the time!"
I refer to the older 235 as one from 1941-49 (mostly military trucks) and 1950-1953 cars & trucks. A "newer" 235 as one from 1954-62 cars & trucks.
The intake ports of a 216 are smaller than the 54-62 235 so fabricated alignment/adapter rings are needed (turbulence?) but a 216 carburetor is undersized (run rich?) and may need modification. The water pump, in the picture, looks like a shortened shaft 1955 2nd or later design so the 216 water pump wasn't used. The water pump pulley and belt doesn't look to be 5/8" (216 truck) so I suspect the 216 crank dampener was not used. Generator or generator pulley changed? The distributor cap looks to be a 216 and if the distributor is a 216 then the drive gear needs to be change to match the 54-62 235 camshaft.
If I was spending money on a new long block, back in the day, I wouldn't mess it up by putting questionable parts on it. On the other hand, if the long block was from a junk yard and was used to keep a farm truck running then I guess it would be good enough.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
Rds Less Taken Good shot on covers,with explanation,thanks. Patricks of phoenix ?? had a lot of info on identifying blocks and saginaws in his catalog. Think he hung it up though !!
Would someone please explain to me why the 1954 cover has vents and the later covers do not.
The vented valve covers were part of the crankcase ventilation system to exhaust contaminated gasses from the crankcase. The road draft tube created a vacuum in the crankcase (@ 30 MPH) and the vented valve cover allowed fresh air to enter, replacing the fumes. Later, GM figured out that unfiltered air, sucking dust and other contamination into the engine, shortened the engine life. The first attempt at fixing this issue was to eliminate the vents and add a vented oil fill cover. Unfortunately filter media was adequate enough to filter only the largest particles and not the dust. Also this system on relied on speed and did not work at idle or lower speed typically seen in a city environment.
The answer had been an option in their truck fleet for years, a closed PCV system which got later incorporated into most engines by the mid sixties.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
The 54 valve cover was the first year for a four bolt cover. The previous 53 and earier cover, had vents along the center of the cover and used a non vented valve cover oil fill cap. Thoe vents allowed air to flow so the road draft tube could work (air through the valve cover, through the pushrod holes in the head, through the drain back holes in the lifter galley to the block). For 54, its the same except the new design and four screw arrangement. I gues they figured the water draining into the motor from the four side slits was just not a good idea, let alone all the dust and jusk from the air drawn through the motor at speed and so the 55 cover did not have the slits and instead of the non vented fill cap got the vented fill cap that was used from 55 through the 63 model year (really 62 but there was one finl 235 application in 63, limited to a four wheel drive).
hint hint 
