Does anyone have a vaccum diagram tahey can post for me? Im having a bit of trouble remembering some hook ups.. My intake is a 1970 and my carb is a 1974 800 cfm... I have 2 pcv valves, 1 on the intake behind the carb n one on the valve cover. do i block one off? Im also not sure about where to hook up the booster and isnt their a port i leave open for the float bowl vent on the carb? theirs also what looks to be a 1/2 fitting on the intake behind the carb that reduces to a smaller vac hose. I though this was for the booster but it looks too small to be for the booster. any help is greatly appreciated buds.. thanks Vin
Vin, There is only one PCV valve on a 350 or 455 Buick. It plugs into the intake manifold behind the carb. There is a large nipple on the front of the Q-jet. It takes a piece of 3/8" fuel line, that bends around the passenger side of the carb to the PCV valve. On the valvecover is a grommet that accepts a metal fitting to which a hose attaches. This hose goes to the Air cleaner assembly. If you are not running the stock air cleaner, put a breather in the valve cover. The power brake hose connects to the intake manifold, on the drivers side behind the carb. On a stock engine, there is a brass fitting. A metal line connects to the fitting, and then a piece of 3/8" rubber line to the power brake check valve in the booster. You can also just use a nipple on the intake, and run a rubber hose from there. The fitting on the back of the carb runs to a vacuum tank to power your climate control doors. The only other hose you need is for a distributor vacuum advance unit. Tap of the appropriate nipple on the frront of the carb, manifold vacuum or ported vacuum, your choice.
AWSOME Larry, what a BIG help man thanks! The brass fitting looks kinda small to me for the booster though, thats y I was lost. Mayby you can help me on this one. What about the vaccume modulator on the tranny? Where does that go on the carb? and also theirs an electrical hook up on my turbo 400 and I dont think their was one on the last tranny that was in the car because I dont see and electrical lines going to the tranny? Their used to be a turbo 350 in it before. This is sawp, I put my 455 and turbo tranny into a '79 Trans Am. Thanks again ~Vinny
Vin, Forgot about the vacuum modulator. That goes into a fitting in the intake manifold just to the drivers side and foward of the PCV valve. The modulator needs a manifold vacuum source. The THM 400 uses an electrical kickdown, the THM 350 used a cable. You'll have to see if you can adapt a gas pedal switch to activate the kickdown like on the GS's. You can tap an ignition on, 12 volts off the fuse block, run it to one side of the switch, then wire the other side of the switch to the transmission connection. I'm sure some of the late 70's Firebird and Camaros had THM 400's in them. See if you can find the gas pedal assembly from one of them in the bone yard.
