Question: 72 Small block exhaust manifolds

[spleech]

Early cars have a different exhaust manifold than late cars...what would be considered early?

 

[Vettehead Mikey]

Best look in an NCRS judging manual. Changeover from early to late config. parts can occur just about anywhere during a production year. Example- the 'early' grills on '73s continued till three weeks before the very end of the production year.

 

[paz72vette]

my 72 was the 6491th produced and is concidered an early production for the electrical. I have a timer for the seat belt light insead of a switch in the belts.


Cheers

 

[6880 Mike]

Early and late almost always pertain to specific running changes made on the assembly line. My NCRS Specifications Guide says 3932461 left and 3989036 right were used early on the base engine cars and are not tapped for AIR except on California cars. Later versions used the 3932461 on both sides. It does not list a date for this change.

What is the time/build date for your car?

 

[spleech]

Early and late almost always pertain to specific running changes made on the assembly line. My NCRS Specifications Guide says 3932461 left and 3989036 right were used early on the base engine cars and are not tapped for AIR except on California cars. Later versions used the 3932461 on both sides. It does not list a date for this change.

What is the time/build date for your car?

Hi,
October 14th is what the birthday book tells me.

 

[6880 Mike]

October was the third month of production and, in a generic sense, could be considered early. I checked the AIM and the NCRS Judging Guide and neither mentions the change in manifolds.

 

[spleech]

October was the third month of production and, in a generic sense, could be considered early. I checked the AIM and the NCRS Judging Guide and neither mentions the change in manifolds.

I also checked the same with no luck. Thanks for doing that, i appreciate it.!

 

[6880 Mike]

I also checked the same with no luck. Thanks for doing that, i appreciate it.!

I'd still like to know when the change occurred.

 

[spleech]

I'd still like to know when the change occurred.

I'm going to contact NCRS to try and find out. I"ll let you know.

 

[Vettehead Mikey]

Another way of skinning the cat would be to look at castings dates on manifolds. If some can be found that are dated a few weeks or a month or more before the assembly date of the engine (not car) it's reasonable to think that this might be the introduction date for the later pieces.

I went through such an issue trying to track down a correctly dated intake for my '73. All the manuals indicated that it should have had a 3997770 or 3997771 casting number, yet I could find none that were reasonably close to the engine assembly date of mid June '73. All I could find were 340261 which supposedly was not introduced until the '74 model year, yet had casting dates that seemed excessively 'early' to coincide with the model year change over. Long story short, it eventually came out that the 061 had been seen on some late production '73s and was a 'legitimate' part number.

 

[spleech]

Another way of skinning the cat would be to look at castings dates on manifolds. If some can be found that are dated a few weeks or a month or more before the assembly date of the engine (not car) it's reasonable to think that this might be the introduction date for the later pieces.

I went through such an issue trying to track down a correctly dated intake for my '73. All the manuals indicated that it should have had a 3997770 or 3997771 casting number, yet I could find none that were reasonably close to the engine assembly date of mid June '73. All I could find were 340261 which supposedly was not introduced until the '74 model year, yet had casting dates that seemed excessively 'early' to coincide with the model year change over. Long story short, it eventually came out that the 061 had been seen on some late production '73s and was a 'legitimate' part number.

I'm going to try and contact a C3 judge at NCRS and see what he says. Thanks for your input!

 

[Vettehead Mikey]

Many of the replies here have been from C3 NCRS judges