strange head number
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Joined: Oct 2004
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strange head number
I pulled the valve covers off my motor, one head has the number: 3927186 with the build date: L18/9, which I believe is correct for the car ( 70 CTH 350-350hp) the other head number is: 398492 build date: A12/1, it has screw in studs and guide plates, Is this a 71 lt-1 head? Or a over the counter replacement head from GM? The ID number is only 6 numbers long instead of seven??? Did GM have alot of warranty problems on vettes in 1970, I have seen alot of talk and questions about CE blocks, what was the problems, thanks, DAVEWSC
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Joined: Feb 2007
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Small Block 186-492 Heads
I pulled the valve covers off my motor, one head has the number: 3927186 with the build date: L18/9, which I believe is correct for the car ( 70 CTH 350-350hp) the other head number is: 398492 build date: A12/1, it has screw in studs and guide plates, Is this a 71 lt-1 head? Or a over the counter replacement head from GM? The ID number is only 6 numbers long instead of seven??? Did GM have alot of warranty problems on vettes in 1970, I have seen alot of talk and questions about CE blocks, what was the problems, thanks, DAVEWSC
When Chevrolet finally ran out of the 186 inventory long after they were used in production they did repairs and warranty with the 492 straight plugs. If you went to the dealer expecting to buy the 186 through the parts department they superseded the number to the 492.
There is also 492 angle plug with a heat crossover for the intake which was over the counter performance only. The 292 turbos replaced these
later but took out the heat passage and made the port bigger. Both the
492 angle and the 292 if I remember had larger ports.
Harry P. Hunter
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Joined: Oct 2004
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Thanks for the info, Harry, I may sell the car some day and everything else is numbers correct and I wasnt sure about what to tell a potential buyer, the reason it had the wrong casting number on that head, When a part like this is changed for waranty reasons does it hurt the value of the car, should I hunt down a 186 head with the right date?
