My TVS is not doing what it is supposed to do according to the extensive reading I have conducted the last days.

The car is a 69 with 350 and auto. No two-way vac. distributor. Manual says three of the five ports on the TVS is to be used, and everything seems to be correctly hooked up.

Pete Serio has a write-up on this in the FAQ section which makes sense to me, but there is a drawing of the various ports and hookup that does not. The excerpt from JimC´s site makes more sense according to the plug layout and my testing.

It is close(port vac to dist.) when cold, but is open(man.vac to dist.) at operating temperature. I don´t have exact temp reading, but my new repro rally gauge reads right in the middle, and everything seems fine. When starting from cold I can observe the temp needle going slightly over middle before the thermostat opens and it settles around middle of scale. No way it reaches 230 in my book.

So, do I have a faulty TVS?
Is there several versions of it around, perhaps with other temp limits?

The correct TVS for our cars has an opening rating of 208-221 degrees F per the manufacturer of replacements. Yours may be just fine, if you took a drive and are idling when you check to see if it's pulling manifold vacuum. You can put a tee in the manifold vacuum line and run it into the passenger compartment and hook it to a vacuum gauge to see under what conditions it switches.

http://www.tomco-inc.com/Catalog/38thermal%20vacuum%20valves.pdf

Firebird Parts Index: 1968 all, 1969 all, 71-72 455HO # 3016754 crossref to Tomco #13200

The PW/PT breakers are here, I will test them ASAP.

I just received my TVS from Tomco #13200 and it has 3 ports. I understood we needed 5 or is the other two just the ones that ended up looped?

Good thing I did not win that 5 port plug/tubes on ebay the other day, I dropped out at around $40.

If the 3 port is ok is there a plug or do I just hook up the vacuum lines to the TVS?

I only seem to see a 1, D, and 2 marked near the ports. Anyone hooked up a 3 port in place of a 5 port, I do not recall those numbers, the 5 port had two letter designations I believe.

The five port factory TVS is fitted with a jumper block that eliminates two ports on a '69. The block is often a hard to diagnose source of vacuum leaks. On earlier models, a service bulletin looped those additional two ports with a hose.

Just hook the vacuum lines up directly. If it did not come with a diagram, connect D to distributor vacuum advance, and to determine which is ported and which is manifold vacuum simply test to see which port is open when cold, and connect that to ported and the other to manifold. The bottom port is most likely the ported vacuum.

Does anyone have a pic of where the TVS goes on the manifold? I have an edelbrock performer manifold without the TVS installed.

Thanks, Brian

Brian,
Here it is on the original GM manifold, up front next to the radiator hose:

Thanks Vikki, I feel better now! (besides I installed it last nite) Today I am outside in the hot sun sanding fenders and trunk lids!