MSgt Luttrell

Ok, here is the latest with my IROC Z28 Project. As I'm going through the car to see exactly what all I need to do to get it in tip top shape and ready for the engine swap next spring, I'm fixing all the little stuff that so many shade tree mechanics are guilty of over looking.

I noticed that my transmission shift points seemed to be too soon and too soft, so I checked the Throttle Valve Cable adjustment on the transmission and found that it was out of adjustment causing early shifts and low line pressure, which we all know is very bad for the transmission. Right away I noticed that the throttle linkage on the Holly 600 Carburator wasn't modified to run with the 700R4 transmission and ordered the correct linkage from Holly's Website.

I'm sure most everybody here knows that what the part does is give the correct ratio of movement between the engine throttle and the transmission valve body; it is the only thing that tells the transmission what the engine is doing on a 700R4 and is critical to performance and transmission life span. Anyway it came in yesterday and this morning I went out and installed the linkage and readjusted the TV Cable. I'm happy to say it runs much better, the performance is what it should be through out the entire range of throttle movement and the shift points are dead on what they should be; she will even bark the tires a little if your foot is in it as it shifts into second.


Here is a pic of how the previous owner had the linkage set up...............




Here the new linkage is installed and adjusted.........






And all buttoned back up................

IroczFan

I hhave the same set up but diffent holley throttle bracket and my trans still shifts to early and I think I have the tv cable set right

IroczFan

What am I doin wrong

MSgt Luttrell

Sounds like you still need some adjustment. I believe the bracket on your pic may have two little screws or bolts that allow you to do minor adjustment near where the TV Cable clips into the bracket. Loosen these two bolts or screws to a point that you can add a small amount of tension to the cable; then tighten the bolts or screws to keep it from moving from where you set it.

Some TV Cable set ups have a way to do the same adjustment at the point where the cable end goes through the point where ot attaches to the carburator. Either way, if your 1-2 shift is happening before 17 MPH, you need to adjust it.

Take it for a test ride, it should shift from 1st to second at low RPM Throttle right at 17 MPH. Keep adjusting and test driving until you have that first shift right and if the rest of the transmission is in good condition, the other shift points will also be dead on correct.

IroczFan

My whole throttle bracket keeps moving I even cranked it down n stripped the intake itself

MSgt Luttrell

Bummer, you're going to need a heli coil for that stripped bolt hole.

IroczFan

Already tapped it out.. I think it will work one size bigger bolt not like your normal carb stud.. bracket still moves scared to crank it down to much. .

Night rider327

iTrader: (13)

Is it just the one bolt that also holds the carb down? If so just drop in another bolt and tighten a nut on it, in the other hole I see in the pic. This will 'bind' that second bolt when you tighten 1st bolt up and stop the bracket from twisting/moving

mr z28

I have the same Holly bracket that irocfan has an when you step on the throttle the bracket moves here is what to do their are 2 holes to mount the bracket the outer hole under the bracket weld a nut to it an put a ellen screw in it it will keep the bracket from not moving to adjust the cable I had the same problem shifts were to early push in on the d button an hold it push the linkage all the way open an then let go of the botton the trans. will set this is what I did an it works great.

IroczFan

Im gonna try something similar with a bolt