I have about 10 pix of 21 stud flatheads saved on my computer and about 100 pix of 24 stud engines. I assume that this is because there are about 10 times as many 24 stud engines posted here than 21 stud engines. I get 99% of my hot rod pix from the H.A.M.B. I keep engine pix in folders named for the engine type. I got to studying them this afternoon and questions began arising in my head. Note: this all got me started when I was reading manitouguy's post asking about engine opinions. ===== The 24 stud heads some have the water outlet: upwards facing at the front, & upwards facing in the center So question number 1: on the 24 stud engines what are the years for each of the water outlet types and are they otherwise the same? ===== The 21 stud heads appear to have the water outlet: forward facing straight out the front, upwards facing at the front, & upwards facing in the center So question number 2: on the 21 stud engines what are the years for each of the water outlet types and are they otherwise the same? ===== On 24 stud heads there are: 2 studs placed vertically in the center of the head, 8 studs (in groups of 4) across the bottom and nearly in line with each other On 21 stud heads there are: 3 studs placed vertically in the center of the head, 8 studs (in groups of 4) across the bottom in a zig zag pattern plus the 3rd stud in the center vertical row The rest of the studs are placed more or less similarly on both types of engines. ===== Question number 3: Are there other obvious differences that I can use to identify an engine; whether between 21 & 24 stud engines or other differences that one can easily see? Well, obviously, you could count the studs but that's not what I'm asking. I'm attaching pix a green 24 stud engine (I believe that this one is NealinCA's) and a red/black 21 stud engine (manitouguy's from his current opinion thread). I chose these pix because they show the stud pattern very clearly. I'm also going to post some engines that I can't identify for obvious reasons. Please identify them if you can. If you identify any of them please tell what clued you in as to what it is. NealinCA 24 stud: manitouguy 21 stud: unknown #1: unknown #2: unknown #3:
1932-36 had lower outlets/motor mounts and water pumps/inlet in the head. 1932 was it's own water pump and lower outlest (almost the entire engine is 1932 only). 33/34 share lower outlets, and 35/36 share lower outlets. 1933-1936 the outlet was also the mount, 1932 had a separate outlet and separate mount. Some minor differences in water 33/34 nd 35/36 water pumps but all interchange. 1937-up had pumps in the block which also acted as the mount. 21 and 24 stud blocks used the same pumps and overall design. The upper water inlet moved to the center of the head. This went up through 1948 and the beginning of the 8BA series. There is a block off plate to use on 37-up blocks and utilize the 36-ealier mounts/heads with water pumps in them. easiest way to quick ID which number of studs a flathead is: Look at the row of studs between the two center spark plugs: 21 stud have three studs in the very center of the head going strait up and down (vertical). 24 stud has two studs in the same spot at the top/middle of the head, but instead of one stud directly below, two branch at the bottom (see your pics above)
I do the 12 bolt rear end trick, we all know a 12 bolt GM rear end has 2 bolts at the bottom of the cover, a 10 bolt has one bolt at 6 o'clock. You don't have to count them. A 21 stud flatty has one stud at 6 o'clock on each cylinder, a 24 stud has 2. This is 24 This is 21 Of course my method requires seeing the bottom row of studs.
The Jalopy Journal
