Radiator Build Sheet Code - 74 BB 4 spd Convertible

[Victor S.]

My parts manual states a MC code for all

[Russ S.]

Re: Radiator Build Sheet Code - 74 BB 4 spd Convertible

I don't know how all 73-74 radiators could have a MC code when there were at least two radiators used-with and with-out transmission cooler.

[Patrick H.]

Re: Radiator Build Sheet Code - 74 BB 4 spd Convertible

I don't know how all 74 radiators could have a MC code when there were at least two radiators used-with and with-out transmission cooler.

Same thought here. There could easily be 4, but there were at least 2 different ones as Russ mentions.

[Victor S.]

Re: Radiator Build Sheet Code - 74 BB 4 spd Convertible

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Thanks for your help.

[Russ S.]

Re: Radiator Build Sheet Code - 74 BB 4 spd Convertible

M3 is the date code. Big block and small block used the same radiator in 73 so I would expect there to be only the two different codes. One for 4spd and the other for automatic with the cooling provisions.

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Thanks for your help.

[Joe L.]

Re: Radiator Build Sheet Code - 74 BB 4 spd Convertible

Ok – thanks for clearing that about additional codes other thanMC. I’m assuming the MD code on my build sheet then is for 74 BB radiators withA/C and manual tranny since those options are also listed on my build sheet andin on my car.
Like I posted before - Harrison is embossed on the passengerradiator side. Under that there is another embossing – it reads M 3. Since the 74 radiator tags only showed the part number and a two letter code I’m assuming the M 3 embossed on the radiator side is a radiator build date of 73 maybe? Just a guess.
Thanks for your help.

Victor-----

MC= radiator for applications with oil cooler (i.e. THM equipped) GM #3030199

MD= radiator for applications without oil cooler (i.e manual transmission) GM #3030132

[Tom R.]

Re: Radiator Build Sheet Code - 74 BB 4 spd Convertible

MC= radiator for applications with oil cooler (i.e. THM equipped) GM #3030199

MD= radiator for applications without oil cooler (i.e manual transmission) GM #3030132

I keep an inventory of buildsheets, actually 73-82 GMAD manifests and have several from 1974. During that period, higher cooling capacities were required for A/C, THM 400 and LS4s. Another code I see used in 1974 is MA installed on L48, M40 but no C60 (A/C). MA is also used on an LS4, M40 and no C60.

The MC code is used on L48 M40 and C60. I have a couple of manifests that show this combination.

The MD code is used with L82, M21 & C60

And to muddle the code use further, I have another 74 manifest and it appears to be an MG with options, L82, M21, non-C60 car.

That makes four!