FOr 232, I the 1950 (first year) heads clearly have the number 500 markedon the top. Subsequent years had 232 marked on the top.

For 48-54, all 262 heads had the number stamped on the top. Of course Hornets had the 308 number on the heads for those engines.

I guess I don't think it's necessary to get the casting number to know which engine the head was built for.

I posted this on facebook as well. The narrow block head has the temp.sender hole about even with #2 cylinder on the head. The wide block head has the temp sender in the back corner. they made replacement cyl.heads for the narrow block from the wide block casting. You can tell this because the head, after installed will hang over the edge of the block. These replacement heads will have the numbers that are normally cast into the head- 262, milled off. Remember the sending unit location, in front is narrow, in back, wide block. These 2 heads do not interchange, BUT have the same bolt pattern and can be installed. The coolant passages are way off between the two. Hope this helps.

'51 to '54 , 232 head has that cast into it. 1950 232 cyl.head will have "500" cast into it, and is '50 only.

Is there any measurement that can be made to identify a narrow block head from a wide block head? Is it fair to say that if the head does not have a large cast number, "232", "262" , "308" it is a narrow block "500", "501" or a 262 head if just a plain casting number with no large number?

Jeff, the easiest way to remember is a narrow block head has the temp.sending unit in front of the head, and wide block has it in the rear. A 232 Pacemaker, 1950 only has 500 on the head, and the sending unit is in the front?-Narrow block -. 1951 and later, all had CID cast into the head. The provision for the heater pipe was also changed to the side of the head instead of on top. Always check the casting numbers for cylinder heads. I have seen 4 different types of narrow block heads. Early '48 narrow block cylinder heads must have had some problems. They sort of had a smooth finish. I have seen several cracked right on top. Then they changed to a little heavier casting, smooth, but not as much, then the narrow 262 head, sometime early in '49 had 3 ribs cast into the length, all 3 inline with the 21 head bolts. The heads all had the rib design from then on. Casting numbers on some heads will identify what the head is. I don't have the number in front of me, but you could have a "232" head and it is a factory 7X type application.

No 501, that number is in the VIN.

[quote="Jeff Duncan" post=19457]Is there any measurement that can be made to identify a narrow block head from a wide block head? Is it fair to say that if the head does not have a large cast number, "232", "262" , "308" it is a narrow block "500", "501" or a 262 head if just a plain casting number with no large number?

Thanks for the help. I had time to get back and look at this today. The casting number is 304621 date B81. I am assuming Feb 8, 1951 which I thought would be a wide block but the temp sender is up front. Also, it looks to have been installed on both a 262 and a 308 as there are two distinct cylinder rings showing on the head. The coolant passages on the cylinder side opposite the valves look to be drilled out as they have a random figure 8 pattern. My thought is this is a narrow block head modified to put on a 308 for higher power and was modified to fit, does this make sense and we're wide blocks not around until 52?

Another question is a 308 head with a casting date of k136, is this Nov 13, 1956 head?

Part#'s starting in '55 had 7 digits, is how I use as a quick reference?. Prior had 6 digits.

Have you taken a new head gasket and layed it on the head and compared the water jacket holes?. I would think if it has been modified, it would have holes, or oblong holes where you wouldn't want them?. I think to insure no future problems with sealing or leaking, you should try and find what is correct for your application. Too much work and grief to do again. Make sure you seal ALL of the head bolts, paint the head gasket with whatever type of sealer works best for you and re-torque after the initial test fire. We warm the engine for about 2 minutes, then re-torque. You will be surprised at how much it changed. Also, MAKE SURE the head bolts are good, and not all eroded/corroded away. If the head bolts are rusty and corroded, they stretch and will probably allow seepage. Trying to re-torque properly will always be a problem. Asking a head bolt that is 65 years old or more to work as new is a little much?. New head bolts are cheap insurance.