engine cyl head # 3731762

[Jim L.]

i'm in search of a picture showing the real head marking "twin tower"on the end of this head. according to my research, there is a truck & a car version. the symbol is the same except the size of the towers differs. my application is for a 56 Corvette & not a truck. i don't want make the mistake & spend hard earned money for the wrong part as these heads are very pricey. a picture is still worth a thousand words as the saying goes, so please share your knowledge with another hobbyist. thanks to all in advance for your help.

[Brooks G.]

Re: engine cyl head # 3731762

Jim, I am going to try to attach pictures to this post. Please tell me if this is what you need or not. I also have pictures of the numbers that would be under the valve cover. Let me know what you need. Brooks Glover (2141)

[Jim L.]

Re: engine cyl head # 3731762

Jim, I am going to try to attach pictures to this post. Please tell me if this is what you need or not. I also have pictures of the numbers that would be under the valve cover. Let me know what you need. Brooks Glover (2141)

Hi Brooks,
I trust you are very bussy getting that 56 of yours on its way to paint by now.
Thanks Brooks for your pictures of the one type of twin tower identifier.
The numbers are not needed at this time but thanks none the less.

Anyone else have another style of twin towers on their heads to compare to these pictures?

[Brooks G.]

Re: engine cyl head # 3731762

Jim, from the pictures, do you have any idea which version of the 3731762 heads that I have? How do you tell the different versions apart? Till now I have always thought these heads were fairly rare and did not know there was more than one version. Mine have the numbers 3731762 cast on them. Do I have cause for concern? Brooks Glover (2141)

[Brooks G.]

Re: engine cyl head # 3731762

Hey Guys! Where are our folks in the know about these heads? According to Jim Lennartz and his research there are two versions of the twin tower 3731762 heads. Supposedly there was one type that was used on trucks. Other than the set I have, I have only seen one other set of these heads. The other set appeared to be like the ones I have. Surely there is a judging team leader of someone who knows about these heads. "Car 54" where are you? The possiblilty that I may have bought the wrong heads has my blood pressure elevated to say in the least. Come on guys, I need some relief. Thanks! Brooks Glover (2141)

[Mike M.]

Re: engine cyl head # 3731762

i've never heard that the truck double tower height was different than the vette double towers but i'll propose the following : all the vette heads were cast in flint and as such will have a SINGLE digit for the cast date year of production. the truck tower heads could have been made in tonowanda ny or flint mi. its possible the tonowand heads with double digits for cast date year may have different size towers. if your 762's were made in flint(have single digit for cast date year), then i wouldn't let it worry me as i can't imagine there being two cast molds used in flint for a truck head and another mould for the vette head.mike

[Edward M.]

Re: engine cyl head # 3731762

OK, Brooks, since this has you so upset, I will resolve the issue for you. Put those heads outside of your garage and I will come by and pick them up. Don't worry about paying me to take them off of your hands, no charge.

OK, here is what Alan Colvin says about these heads:

"This cylinder head was released late in the 1956 model year. It had the same small combustion chamber as the #3725306 head. It was identical with #3703523 except that the valve guide boss diameter has been increased. There was also a truck version of this cylinder head released, but it had a much larger combustion chamber and a large "T" in the middle of the rocker arm area. The truck #3731762 cylinder head "twin tower" external head marking is also slightly different from the passenger car cylinder head. The towers are taller and closer togerther (1959). This cylinder head was also used in early 1957 production."

Do your heads have a "T" in the rocker arm area?

[Mike M.]

Re: engine cyl head # 3731762

T in rocker area = tonowanda?bet that's the case.mike

[Gary C.]

Re: engine cyl head # 3731762

Mike, wouldn't the tower area be rough cast rather than machined line Flint heads? Gary....

[Mike M.]

Re: engine cyl head # 3731762

Mike, wouldn't the tower area be rough cast rather than machined line Flint heads? Gary....

yes, i'd expect the doulbe towers to be sand cast in appearance if they are tonowand origin/. mike

[Edward M.]

Re: engine cyl head # 3731762

Check out the difference in the symbols on these cylinder heads

The first picture is a 3731762 head dated 1956. The second picture is a 3731762 head dated 1959.

According to some info on the classic chevy site, the 1959 heads are the truck heads. The combustion chamber is bigger, but the heads can be shaved down to get the correct size combustion chamber. However, the combustion chamber shape is also different.

The truck heads also have a 'T' cast into the valve cover area, which also can be removed by a grinder.

Notice the difference in size of the 'rectangle' that the towers sit on top of. This MAY be a way to tell the difference when the valve covers are installed.

The size and distance between the 'towers' also appears to be different. Interesting.

[Edward M.]

Re: engine cyl head # 3731762

OK, a followup. Neither of the heads pictured has a 'T' cast into it. The head with the 1959 date code is the second head.

I suspect thaty most likely this is a service replacement head. This is the second set of 3731762 heads I have seen with a 1959 date code.

[Colin D.]

Re: engine cyl head # 3731762

I was told that the heads were cast at 2 plants. It was my understanding that the 1959 date was a casting error on the tonowanda heads being that the 6 was cast upsidedown. Why would GM use the same part number on truck heads 3 years later? That makes no sense.

[Edward M.]

Re: engine cyl head # 3731762

I was told that the heads were cast at 2 plants. It was my understanding that the 1959 date was a casting error on the tonowanda heads being that the 6 was cast upsidedown. Why would GM use the same part number on truck heads 3 years later? That makes no sense.

I can see that sort of error on a specific date, but the same error on multiple dates is a stretch. I know of two different sets of heads dated 1959, and they do not have the same dates. Could happen I guess.

What is the source of your information about the upside down date. I am not saying it is wrong, just want to try and pin the info down.

I too am puzzled by GM using the same casting number for two heads that are configured differently. The combustion chamber shape and size is different between the 1956 2x4 head and the truck head (which is either dated 1957 or 1959; I have seen reference to both dates when discussing these heads).

[Colin D.]

Re: engine cyl head # 3731762

I learned this from an old corvette parts guy that I have been getting parts from for years. off the top of my head his first name is Joe and he sells lots of parts out on the west coast. I was told by him that it was a known casting error in '56 and that GM never used the casting number 3731762 in 1959. I did some research and didn't find this casting number used in '59 either. I figured his info to be legit after that. I could see that the date would be cast upsidedown but a part number casting error was less likely. Then again I have only seen one head dated like this. I would be interested in knowing the months of others that have these 59 heads to compare. I think the head I saw was dated F269.