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#1
07-26-2023, 07:13 PM
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Tri-Power Thermostatic Vacuum Switch Block Off Plate - To Mount Aftermarket Gauge
Does anyone manufacture one of these plates in 1/2” thick steel with a 1/2 NPT tapped hole in the center?
Rather than make my own I’m wondering of this piece is offered by the Tri-Power specialists for those not running vacuum linkage. It’s the perfect spot to mount a water temperature gauge. The block off plate I have pictured is only .110” thick, I’m thinking something around .500” thick would allow enough 1/2 NPT thread depth to seal the fitting.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
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#2
07-26-2023, 10:18 PM
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I could never find one. I had to have a local shop make me one.
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The '64 GTO The '65 Chevelle The '69 Chevy Pickup Project The Brazen Orange 2006 GTO |
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#3
07-26-2023, 11:34 PM
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I picked up a '64 389 50 yrs. ago to replace the '65 YF B-body engine in my '64 GTO. It came with a foreign fitting on the rear of the left head covering freeze plug opening. It was a pump flange for a residential heating system. It had, IIRC, a 3/4" pipe thread tapping. This may be an option. I will search for it tomorrow.
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#4
07-27-2023, 12:15 AM
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Drill a hole, weld a bung, and tap for NPT. No reason to make a new plate.
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
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#5
07-27-2023, 01:14 AM
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I’d much rather have the cleaner look of a thick plate rather than weld something up, but thanks for the suggestion.
Once you weld a 1/2” pipe half coupling onto that thin plate it’s going to warp, after surfacing it would be too thin for my liking.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
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#6
07-27-2023, 08:32 AM
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The standard block off plate is not thick enough, not enough meat there to accept threads that would seal. I used 3/8" thick steel which is the minimum thickness I would use. For anyone who is curious, there is enough room behind the plate for the temp sending unit to be in the coolant flow and not bottom out against the inside of the manifold.
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The '64 GTO The '65 Chevelle The '69 Chevy Pickup Project The Brazen Orange 2006 GTO |
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#7
07-27-2023, 10:43 AM
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I just drilled and tapped it. Worked for years.
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#8
07-27-2023, 11:52 AM
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This is the pump flange I mentioned. It is 0.250” thick and tapped 1/2” NPT. Not sure how the PO used it on the rear of the LH head. Maybe a sensor or tried something for better coolant flow.
Clearance to firewall is about 3 1/2”. It would less conspicuous back there if there is enough space. Optional location would be RH head front if no a/c or alt. there. The key will be finding the correct bolt pattern. It’s a flange for a hydronic heating pimp. Ck local plumbing/heating supply houses or HVAC contractors. Sorry, can’t get pics upright. Last edited by GtoFM; 07-27-2023 at 12:08 PM. |
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