Topic: 67 Small Block Thermactor Valve Mount Change Date

[67gtasanjose]

I have 2-questions, related, but slightly off topic:

1.) Any idea when the transition from "early", two-piece gulp, backfire, diverter valve bracket  C60E-B to the one piece version C60E-D took place? (see pictures)

2.) Does the "longer" version apply to 4-barrel carb (A-code), shorter to the 2-barrel (C-code) or any other knowledge of the "why" related to the two-piece version?

[67gta289]

I can offer that my Dec 20 66 SJ C code was the later one piece design.  However, since thermactor equipped engines had unique engine codes, I would assume that the bracket installation was at the engine plant, and the assembly plant would not matter.  As always I'm willing to learn though.

My engine was built in Windsor (E) in December (M) but no specific December day listed.  It is revision level 15.  Code E-236-B

If the change was related to the engine revision (I have no reason to suspect it is or is not) note that the level 14 to 15 transition date was supposedly mid November 66 for Windsor (my Dec 66 supports that), but not until March or April of 67 for Cleveland.  Very strange.  Mannel's book states that the purpose of level 15 changes were related to emissions as well as accessory pulleys.  The discussion about emissions was centered around performance/calibration. 

The brackets appear to be the same overall physically in terms of mounting, and they would not change the performance/calibration, so they were not necessarily part of the level 15 change.  I bring that up only as reference information.

[67gtasanjose]

I can offer that my Dec 20 66 SJ C code was the later one piece design.  However, since thermactor equipped engines had unique engine codes, I would assume that the bracket installation was at the engine plant, and the assembly plant would not matter.  As always I'm willing to learn though.

My engine was built in Windsor (E) in December (M) but no specific December day listed.  It is revision level 15.  Code E-236-B

If the change was related to the engine revision (I have no reason to suspect it is or is not) note that the level 14 to 15 transition date was supposedly mid November 66 for Windsor (my Dec 66 supports that), but not until March or April of 67 for Cleveland.  Very strange.  Mannel's book states that the purpose of level 15 changes were related to emissions as well as accessory pulleys.  The discussion about emissions was centered around performance/calibration. 

The brackets appear to be the same overall physically in terms of mounting, and they would not change the performance/calibration, so they were not necessarily part of the level 15 change.  I bring that up only as reference information.

Thanks John, so my basic question could go even further down the road to "I don't know where or why".

I have both brackets shown in my previous picture and currently, I intend to use the one-piece, C60E-D bracket on my 11/66 built A-code. I did know that the change-over level date situation is around-about that time frame going by my best information I know of to date anyways.

FWIW, the C60E-B bracket with the 1-inch adapter plate came with some '66 289 parts I bought so maybe not even relevant or correct to use on any 67 for all I know. I've heard that some EARLY 67 289 Thermactor cars still had the multi-tube "rake" A.I.R. tubes like the 66's had so I wonder if the change-over has anything to do with that particular change level...Maybe this inquiry ties a few of these loose ends up, I guess we'll see 

Maybe these questions best suited to another thread? Jeff or any Admin, what do you think?

[J_Speegle]

Maybe these questions best suited to another thread? Jeff or any Admin, what do you think?

Done - sorry had some connection issues this week. Will check my  files to see if I can add some dates or data points  in a day or so