292 vacuum after swap to auto trans

[tate65]

The 80 c20 we just picked up had the trans swapped from manuel to auto. The guy said he didn't bother with vacuum he was manuely shifting the 3 speeds himself. It looks like the only line he has goes to the new distributer HEI and brakes. . I cant find a diagram with the min necessary for the setup we now have. What do I need? Not need...Stock carb. No ac but need heater vents to work

[cadillac_al]

I forget where the vacuum ports are on the six's but they can't be that hard to find. You can't run an old automatic trans without vacuum. That tells me a lot about the IQ of the seller. The truck probably has a few other hacks too. Somebody may post a pic of the vacuum ports for you or you may be able to google it. Good luck.

[tate65]

Originally Posted by cadillac_al

I forget where the vacuum ports are on the six's but they can't be that hard to find. You can't run an old automatic trans without vacuum. That tells me a lot about the IQ of the seller. The truck probably has a few other hacks too. Somebody may post a pic of the vacuum ports for you or you may be able to google it. Good luck.

Yeah he probably had 3x what we paid for it in upgrades, I think he had his wife on him to get rid of it. Makes a perfect project for the 15 year old boy. It's been 30 years since I rebuilt my 69 Cutlass so this is a brain refresher for an old man.

[Dead Parrot]

Assuming a TH350 for the transmission, there is a manifold vacuum connection to the modulator on the passenger side. Normally a metal line travels most of the way to the intake manifold port.

Not sure about heat only systems. On AC trucks, there is a plastic vacuum container about softball sized on the passenger side of the engine compartment. Follow the line to a T. One branch of the T goes into the cab to operate the various flapper doors. The other branch also goes to manifold vacuum.

[cheap]

There won't be a vacuum canister like there is on AC trucks usually. The vacuum modulator will be on the passenger side of the trans, just hook a vacuum from that to a vacuum on the intake or carburetor.