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#1
02-23-2022, 08:23 AM
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71 455HO TCS
it was recently pointed out to me (at the 2021 MCACN) that a 71 455HO should have a TCS system like all of the non HO applications. After looking through the factory shop manual, my take away is the HO cars were not equipped.
Naturally, I was dinged points as I was not able provide a valid counter point to the conversation. If it is supposed to have it, anyone have a nice survivor type solenoid around? Thanks, Tim |
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#2
02-23-2022, 08:52 AM
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455 HO uses 'TVS' system. There would be a fitting in same spot as TCS.
Just found this in parts book: 
__________________
John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates Last edited by johnta1; 02-23-2022 at 09:16 AM. |
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#3
02-23-2022, 09:38 AM
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How does the system know when the vehicle is in high gear?
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1978 Black & Gold T/A [complete 70 Ram Air III (carb to pan) PQ and 12 bolt], fully loaded, deluxe, WS6, T-Top car - 1972 Formula 455HO Ram Air numbers matching Julep Green - 1971 T/A 455, 320 CFM Eheads, RP cam, Doug's headers, Fuel injection, TKX 5 Spd. 12 Bolt 3.73, 4 wheel disc. All A/C cars |
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#4
02-23-2022, 09:56 AM
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A switch on the trans when shifting into 4th gear with a manual trans.
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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule. |
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#5
02-23-2022, 10:08 AM
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Thanks for the replies so far guys. So if I am reading the provided information correctly, the 455HO just uses a ported vacuum switch regulated strictly by engine temp (which I have).
I was informed it should have the vacuum switch which was electrically controlled by the trans when it's in 3rd or 4th gear. Sorry if I am not explaining myself properly or complicating things. I am very familiar with TCS systems from my Corvette background. Just wanting to make sure I have thing correct on my car, but do not want to alter anything due to a misinformed judge. |
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#6
02-23-2022, 10:25 AM
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I don't think the 455 HO had a switch on tranny to control the TVS?
(or had a TCS vacuum switch for distributor) Quote:
It was just vacuum operated. (and heat from intake crossover) Another page on checking the TVS (455 HO) 1971 TVS (full page link so not crunched down by PY)
__________________
John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
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#7
02-25-2022, 05:04 PM
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No TCS on a ‘71 HO. They have a thermal vac switch on the right front of the intake. It has a ported vac input and a manifold vac input, and distributor advance output ( so 3 ports) Then the thermal switch opens one vacuum source cold and the other when hot, but no dist vac advance during normal operating temp. Not the best for driveability but sure lowers NOx emissions.
It is documented in the ‘71 service manual and assembly manual. |
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#8
02-25-2022, 06:19 PM
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Quote:
FWIW |
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#9
02-25-2022, 06:44 PM
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Quote:
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#10
02-25-2022, 07:25 PM
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Removed and posted new thread
Last edited by hiyabradHO; 02-25-2022 at 07:56 PM. |
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#11
02-25-2022, 07:42 PM
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Tim,
As you have recently observed, the 1971 455HO did not use the TCS system. However, when I owned your car, I noted that there was a TCS switch installed in the transmission, but there was no wire plugged onto the switch. A few days ago I pulled the engine and trans out of my 1971 Formula 455HO and found the same thing. A TCS switch is installed in the transmission, but there is no wire connected to it, and no TCS solenoid on the engine. Quote:
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#12
02-25-2022, 08:59 PM
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I'd imagine the Muncies all came with the hole for the switch and they put a TCS switch in there? (instead of pipe plug)
Also probably they don't know what vehicle/engine will get the tranny, so all have the switch in it. 
__________________
John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
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#13
02-28-2022, 10:01 AM
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Thanks everyone for the help!
Tim |
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