'74 challenger trans issue

[Iceman247]

I have a '74 challenger that i purchased a few months ago with a 360 bored .020 over and a 727 trans. Just put a new 2000-2500 stall converter and flex plate in it and when I put it in gear it want to kill the motor (which this is what it was doing before, figured it was because of a factory converter. Anyone have any suggestions?

 

[challenger6pak]

There are many possibilities. To start with where is your engine timing set? Has it "jumped time"? How about vacuum leaks. Are there any? Will the transmission make the car move at all, if you can keep it running? Basically, is the transmission pump working? There any many other things. We will help you figure it out by process of elimination. Welcome to the site.

 

[moparleo]

Like challenger6pak says, we need more information. How does it run when you start the motor and just idle? Is it smooth ? When you start the engine , the front trans pump only works in neutral. This is a bit of info for you guys who have a delay when going from park to reverse or drive. Start the car, put it in neutral for a few seconds and then back to drive and your car will now instantly go into gears, no lag.

 

[Iceman247]

It's about 8 or 9 degrees, no vacuum leaks that I've found. the car will move if i keep it running but doesn't want to. I'm going to unhook one of the trans lines this evening and see if it is pumping.

 

[Iceman247]

engine starts fine, idles smooth

 

[moparleo]

Does the engine stall immediately when you put it into gear ? Disconnecting the trans line will not really help. The valve body will determine the trans fluids internal paths. What is the idle speed ? Tune specs for 74 360 should be 5degrees btdc at idle. Idle speed 850 rpm.

 

[Iceman247]

with in 2 or 3 seconds, idle rpm is set to about 1400 in park. It doesn't like much lower than 8 or 9 it then doesn't want to start.

 

[Iceman247]

it also has a pretty good size cam in it but not sure of the specs.

 

[challenger6pak]

How many pounds of vaccum do you have? Are you running a vaccum advance that may not have enough vaccum to advance? With the idle up you may be overcomming it with mechanical advance. What carb is on the car? Too small of jets? Is the motor flooding out?

 

[moparleo]

Sounds more like an engine problem than a transmission problem. Lets sort out the engine first. You need to find out what the previous owner did to the car before you try to diagnose and fix the other problems. When doing any kind of diagnosing you need to always start at the beginning. You may not be able to correct the problems without replacing major internal engine parts, rather than trying to adjust things. This is the reason that repair shops do not like to try to fix someone elses problems. They have to try to guess what someone else did and usually have to do a teardown to determine what to do.

 

[Iceman247]

I just rebuilt it myself but had all the machine work done in a shop. The heads were completely reworked and shaved, bored .020 over with 9:1 flat top pistons, crank was polished. has a holley dominator intake with a holley 670 street avenger double pump carb but I don't remember the specs on the cam though. It's an electronic ignition with vacuum advance. Not sure on how to check the vacuum pressure? Motor doesn't flood out, plugs look like they are burning clean.

 

[Iceman247]

I also had someone over last night to look at it and they think the converter is still to low and suggested a 3500-4000 stall and also think i have a problem with the kick down arm sticking. Any thoughts on that? I really appreciate all your guys input, thank you so much.

 

[moparleo]

The torque convertor is not the problem. Putting a higher stall convertor is just trying to mask the real problem. The engine needs to be sorted out first. Remember that every system must work in harmony with the rest of the drivetrain. You will get a million suggestions on line because every one is guessing what you have. We can't really give you any specific remedies as we aren't there to see what we are dealing with. My recommendation, take the car to a quality shop that does high performance engine/trans work to get a true suggestion on what to do. You will save time and money in the end.

 

[challenger6pak]

I agree with Leo. Also if your cam works with the cylinder pressure of 9:1 compression, you will not need a 3500 or larger stall converter. If you need more converter than you have, due to your cam, you do not have enough compression for the cam. Start at square one and find out all the specs for the parts in your motor. Sounds like you have too much cam for the motor.

 

[Iceman247]

Thanks guys for all your input, I actually decided to tear the top end back down and I have ordered a new cam and lifters and timing chain for it recommended by the shop that did the machine work for me. Should arrive this evening. Thanks again I really appreciate the help.

 

[moparleo]

Excellent. Please keep us posted.

 

[Iceman247]

Do you guys know if the 74 Challenger with the 727 used a kickdown cable or rod?

 

[moparleo]

Definitely an adjustable rod. GM & Ford used cables.

 

[challenger6pak]

There is an aftermarket cable kickdown by Lokar and other like companies. Is it a chrome set up? Can you post a pic?

 

[Iceman247]

I haven't hooked everything back up yet just want to make sure i have the right linkage but not sure about the bracket.