The Stovebolt Site Forums The Shop Area Engine Shop Pushrod Length 235 PG Engine

My first time posting.

1957 Chevy 235 PG engine sitting on engine cradle. Block: 3837004. Head: 3836848. Hydraulic lifters (maybe VL46 but not original).

I measured the pushrod length on my engine and they are 11 and 1/4 inches. If I am reading correctly, the 1929-57 Master Parts Catalog says 56-57 All 6 cyl have 11 and 13/32 inch pushrods (hydraulic and solid lifters the same length). Some of the rocker arm adjuster screws are about two rounds of thread remaining before being flush with the top of the lock nut. The engine was running before I bought it ($100). It has 3 bent pushrods but I suspect the 11 and 1/4 inch pushrods did not cause this problem but I really don't know. I've read other postings that point to sticking/worn rocker arms and/or valve guides. I would appreciate it if some of the more experienced folks could give me their opinion before I tear into the engine. I also wonder why the longer pushrods beginning in 1956. Thanks.

It almost looks like you have ones from the 1952 PG.

Be sure you indeed have a '57 235. The lifters for that year only are different than the '55-'62 lifters. There is a date code on the block above the starter. It will have a letter followed by some numbers. For example F 14 7. Would translate into June 14, 1957. The same number is on the inside of the block wall near the crankshaft. You'll have to remove the oil pan to see that code.
That head you have "848" is the good one. Made '58-'62. Remove the valve cover to see the date code on the top of the head. That code translates similar to the block date code.

The block date code is G2357 (July 23 1957) and the head date code is C2257 (March 22 1957). I slid a couple rocker arms over against the spring on the shaft. They didn't want to move at first. There is hard black build-up where the rockers run.

The parts book seems to be a misprint.
I have a dozen sets of original 1953-62 235 hydraulic push rods and they are just over 11 and 1/4" (actually 11.287").
The 1950-52 push rods are 11.250" as the parts book states and they have a groove across the bottom face to vent trapped air from the lifter ( PICTURE ).

Pre'68Dave, thanks for the input. Okay, the lengths are the same. Now I wonder if there is some other difference like diameter or material composition. The Master Parts list shows a part number 3836260 for 1956-57 and (3835777) for 1950-55. I would not think Chevrolet created a new number for the same part.

If you read the 1957 parts book correctly it says:
"1950-52 Pass with Power Glide 3835777", which is a hydraulic lifter engine.
"1953-55 W/PG, and 1956-57 ALL". 1953-55 W/PG is a hydraulic lifter engine, and 1956 started the shorter lifter that matches the length of the hydraulic lifter, so it uses the same push rod.
The 3835777 push rod is different mainly in that it is grooved across the bottom face (see link in above post). In 1953 they dropped the groove, thus a different part number.

Thanks again. You are correct. I was reading it that 50-52 and 53-55 were the same but they are not.

I'm going to straighten up the bent pushrods, clean up the rockers and replace the oil. Maybe I can get this old beast to fire-up.