chironug

Having a lot of fun driving, but for some reason it seems to be kind of hesitant when I really get on to it. I used to have a '79 Camaro with a 350 and if I pushed it to the floor, it would spin the tires like nobodies business. When I do it in the '67 442 seems like it gets kind of bogged down. I'm thinking it is something with the carburetor. What do you guys think?

oldcutlass

The 67 is different than your Camaro in a few ways if it's an automatic. It should have a Switch Pitch T400 in it. The kick down is controlled through a throttle linkage coupled switch at the firewall, also in this switch is your torque converter vane position control. You are going to have to make sure that both of those signals are getting to your transmission.


The other thing you need to make sure of is that your timing is set and advancing properly. Also double check that your vacuum advance is operating correctly and not sticking.

Smitty275

You should also verify that the secondary air door on the carburetor is not loose. If it is opening too soon it will cause a bog until the engine gets enough RPM to do over come the lack of vacuum from the over carburetion condition.

MDchanic

Plus [sounding like a broken record here], leaky spark plug wires, or a bad coil, distributor cap, or condenser, can cause inadequate voltage delivery at the plugs, which reduces performance under high-heat and high-pressure combustion chamber conditions, and is felt as a bog or flattening when flooring it.

- Eric

BlackGold

Agreed. The secondary air valve opening too quickly is probably the #1 performance problem people have with their Quadrajet -- often self-imposed, as people seem to think it should open quicker, so they adjust it that way. Heck, I think the factory's settings are often too "loose."

Also, note that the wrap spring is only one adjustment on the secondary air valve. The dominant adjustment for when you transition to WOT is the vacuum break -- aka ckoke pull-off. In addition to cracking the choke butterfly to help start the engine, the Rochester engineers ingeniously used this thing to control the RATE at which the secondary air valve can open. Basicelly, they make the valve fight against the vacuum break, which has to suck air through its tiny orifice. The things to look out for are, first, to make sure the air valve's linkage is adjusted to fight against the vacuum break from the get-go (no extra slop), and second, to make sure you have a small enough orifice . In our one-size-fits-all world of replacement parts, many choke pull-offs have a very large orifice, allowing the air valve to open too fast. Find one with a smaller orifice. Or you can plug the hole with epoxy and re-drill it with a pin vice.