Hi All, I am trying to determine when a specific cylinder head was available on a production vehicle. All of the restoration reference materials that I have state that the 1956 Cheverolet/Corvette cylinder head, part # 3731762 as used on the 225hp 2 x 4 carb motor was introduced in mid to late 1956, but I also have documentation that states the 225 motor was available in the passenger car on Feb 16, 1956. There is also a fellow who swears that his friend has a 762 head with a January date code....confusion! If the 762 head was not available until late '56, what cylinder heads, intake and exhaust manifolds were used on the Feb passenger cars? I know that the 1st design '56 Corvette 2 x 4 motor used the 3725306 head, 3728725 intake manifold and rare 2 bolt flanged rams horn exhaust manifold 3725563, but supposedly the 725 manifold and 563 exhaust manifolds were never used for the passenger car.......a can of worms. The 3731762 heads were used in conjuction with the 2nd design intake manifold 3731394, and exhaust manifolds 3731558 and 3731557 right/left all with ports larger than the 1st design stuff! Thanks! John
i asked this question to my friend Dave lewis [he wrote "the small block chevy interchange manual"] this is his reply; Hi Ted. It doesn't come as any big surprise that high performance Corvette parts showed up on six cylinder passenger cars before or after they were released as Corvette original equipment. The Blue-Flame and Thrift-King 235 cu in six engines are not something I made it a point to learn about but I think they came in two versions (125 hp and 115 hp) in passenger cars predating the release of the Corvette with a 235 six. The Corvette got a hotter version of the Blue-Flame with three carburetors a solid-lifter cam and a cylinder head with a combustion chamber which may have been smaller to create more compression in order to get that 225 hp rating. The high performance cylinder head, special cam, intake & exhaust manifolds and maybe even the carburetors, were undoubtedly available as service parts... maybe as early as January of the first production year these items were available on Corvettes released later in the year. And, these high performance parts were certainly available to everyone as service parts after the Corvette's with their hot sixes were available to the public. Insiders at dealerships or assembly plants routinely find out that special high performance parts are available before the release of the production versions as service parts and get them for installation on passenger cars they own. This is why many service parts have casting dates that are sometimes much earlier than the production dates of the vehicles having such parts as original equipment. The message poster has probably found a documented case of a special order car or a modified vehicle showing special parts thereby causing the confusion. I found an original 350 in a (numbers matching) 1966 Caprice. The block date code was clearly F-12-6 making this engine block from mid-June of 1966. Yet the 350 cu in V-8 was only first available to the general public as a Rally Sport Camaro option beginning in August of 1966 for the 1967 model year. The reason? The owner was a high ranking GM tool and dye maker assigned to a Fisher Body Plant in Willow Springs Illinois and the car was given the best of everything available during its final assembly in Ohio on the sly. I was assured it had never been apart (until I bought the car). I was told for years the vehicle had a special engine displacing 350 cubic inches which is why I bought it. At first glance it looked like any other V-8 but the air cleaner decal stated it had 350 cu in with 295 hp. The size of the harmonic balancer (8 inch) shocked me and I could hardly wait to get it apart. Everything I was told about the engine was a fact... Stuff happens... Dave
Date codes seem to cause confusion when one fails to consider that PRODUCTION of a part takes time and that the casting process is the very first step in the pathway to being a finished part that has to wend it's way through the system to actually be installed at the factory or sold over the counter. Ray
At first I thought you were talking about the 225 2x4 V-8 . Then the next post was about 6 cyl. I am really confused.
a january date code would be right. in 56-57 we did not have just in time manufacturing like now. parts could be made 6 months or more inadvance of being used. other things restorers don't think about. an earley 55 car goes back to the dealer in mid 57 with a head problem that calls for new heads under warenity. do you think that dealer is going to try to match date codes?
I appreciate all of the responses and yes, I am talking about the 225 HP 2 x 4 carb V8 motor. The question still remains.....if the 762 head was not released until late '56, what head was used on the early to mid year 225 hp 2 x 4 carb V8 passenger car V8 that was available on Feb 16th of '56? John
The only small blocks that had the 8" balancer were the '67-'69 302's and the 365 hp 327... Maybe even the 375 hp fuelie 327.. The rest got the 6" dia. balancer.. I'm not sure about the '70 and newer LT-1 350...
I thinking warranties back them were something less than a year and maybe only 90 days? But it certainly could have been done as typical paid for repair
if you worked for GM back in the day your sbc whatever cubic inch could have a 8" balancer or just about anything you had money for.
it's good to be a HOT ROD guy. we don't need no stinking date codes. I had a 1956 standard bore 265. I had several restorer types who called on it but did not buy it due to the date code. people are weird.
A person sent me a piece of documentation and there is a strong indication of the early availability of the 762 head in Section b. The "new inlet manifold" could quite possible be the 394 manifold as the ports are too large for the 306 heads........that would also indicate that the 762 heads were available in Feb as the 394 manifold and 762 heads were designed as a package. John
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