nasa0306

I could use some advice here, I have a 72 cutlass supreme with a brand new 350 and a th350. It was running fine, driving it daily, then i decided it was time to install new headers. Got the headers in and on my drive home form the shop, at a light when i pressed on the gas, it started to surge and almost died. Being used to to my car dieing on me, i quickly pulled into a parking lot. After some poking and prodding, i pressed and went home without a hitch. However, the car will no stall out when put into drive. Idles fine in park at 1100 rpms with 20 inches of vacuum, when put in reverse it idles just fine at 900rpms and 13-15 inches of vacuum. It will most of the time die immediately when placed in to any forward gear. Occasionally it will struggle a little before it dies, the rpm's will fight to stay alive. I got lucky a few times and it actually idled in drive, but once i pressed on the throttle, back to dying. I've changed around the timing to hope it would help, also adjusted the idle speed and mix, nothign seems to help it. Any ideas????

oldcutlass

What are your timing and if you have points dwell setting?

nasa0306

I have an HEI setup with 13degrees initial.

Railguy

1100 rpm idle sounds high for an auto.And when it shuts off when put in gear reminds me mine when the octane was two low.Of coarse if it just started doing that out of the blue than that's probably not the problem.I think I would look what the idle should be and go from there.
railguy

MDchanic

Do you have a large cam, or anything else that would interfere with a normal idle?

The reason I ask is that the specified idle speed is 600 RPM in Drive for that car, and you say yours is 900 RPM, with a screaming 1100 RPM in Park.
If you've got a huge cam, then those may be the best you can get, but if you have a normal cam, then something's wrong if it won't idle below 900, and the first thing to look for is always a vacuum leak.

- Eric

nasa0306

It has a step above stock for a cam, nothing crazy at all. I will try to lower it down tomorrow and see what i can get. I also think my shift linkage may be moving a wire and cutting off my ignition when i put it in drive.

oldcutlass

In my opinion, with the HEI, your timing sounds a bit low. Have you checked your timing at 3200 RPM with vacuum disconnected? It should be somewhere around 34*. Also as stated above, I think your idle is way to high, it should be some where around 700 -750 in gear.

Does it run rough at lower idle RPM's? Is it running rich at idle? Is the choke pulling all the way off when it warms up?

nasa0306

Well first off, it was the linkage hitting the connection from the starter to the distributor that was shutting the car off. I re-routed the wire some and managed to fix that, when i get off work today i'm going to run a new wire entirely and hopefully rid myself of that connection. I also dropped the idle to 900 in park and about 700 in drive. It was hurting a little so i advanced it to 16 and it livened up. The engine is brand new just built, i pulled the plugs on it the other night and they look as if they've been running lean. Oh and yes the choke comes off once warmed up.