489 3:23 suretrac is here.. Now to swap them out.

[BeepBeepRR]

Mike just bought a suretrac setup I will be pulling the 489 out today and installing the new 489 sure trac with 3:23's and a 7290 yoke. Today will be the first time its been on the road in almost 2 years. I mean other than taking it up to put gas in it.

 

[Jerry Hall]

The music in that is: "Back on the road again"

 

[eldubb440]

The music in that is: "Back on the road again"

(30) Willie Nelson - On The Road Again (Official Audio) - YouTube

 

[BeepBeepRR]

Here are a few pictures of the jack cradle i threw together so I wouldn't have to bench press 80 pounds from the ground. Welded it to my crappy jack with some tack welds. It will come off pretty easy. Sure beats getting your skull crushed.

 

[BeepBeepRR]

Now just have to tackle the hard brake peddle. I checked all over with propane to see if I had a massive vacuum leak and found nothing. Then I started reading about Holley Sniper tuning. Before with just the Sniper the car had decent brakes. Didn't do this till after the Hyper Spark. I bumped the timing up to static of 15 degrees but it didnt change. I have 11Hg of vacuum at idle. Which is not good by any stretch. I'm considering an electric vacuum pump to resolve the issue.

 

[Jerry Hall]

I'm considering an electric vacuum pump to resolve the issue

Agree.

 

[66Satellite47]

Dumb question, doesn't low vacuum create a soft and long peddle travel not hard? 11 Hg sounds fairly good.

 

[BeepBeepRR]

Dumb question, doesn't low vacuum create a soft and long peddle travel not hard? 11 Hg sounds fairly good.

Everything I have read says you need 16 to 18 hg for it to work efficiently. It was at like 16 before the swap to hyper spark. The initial timing was somewhere around 16 degrees.. I'm not sure about the hard peddle but one would think that the culprit would be the low vacuum. One thing I noticed was the lack of a one way booster valve. Meaning it can't keep the pressure. Pretty sure thats not the issue though since they worked fine before.

Read this.
https://techtalk.mpbrakes.com/measuring-engine-vacuum-hard-brake-pedal

And this.
https://www.knowyourparts.com/techn...-brake-components/vacuum-booster-diagnostics/

HARD BRAKE PEDAL Lack of power assist may be due to low engine vacuum, a leaky vacuum hose to the brake booster, or a defective brake booster. The booster is located between the master brake cylinder and firewall in the engine compartment. Sometimes a faulty check valve will allow vacuum to bleed out of the booster causing a hard pedal when the brakes are applied. This condition can be diagnosed by starting the engine (to build vacuum), shutting it off, waiting four or five minutes, then trying the brakes to see if there is power assist. No assist means a new check valve is needed.

A quick way to check the vacuum booster is to pump the brake pedal several times with the engine off to bleed off any vacuum that may still be in the unit. Then hold your foot on the pedal and start the engine. If the booster is working, the amount of effort required to hold the pedal should drop and the pedal itself may depress slightly. If nothing happens and the vacuum connections to the booster unit are okay, a new booster is needed (the vacuum hose should be replaced, too).

 

[66Satellite47]

Interesting, did you try disconnecting the vacuum hose to the trans?

 

[BeepBeepRR]

Interesting, did you try disconnecting the vacuum hose to the trans?

No offence but Mopars do not use a modulator valve like chevys. There is no vacuum on the 727. That is what the kick down linkage is for pump pressure.

 

[BeepBeepRR]

OK took it up to the local McDonalds and put 20 bucks worth of gas in it. At 3.06 a gallon. Anyhow I was not sure how much gas was in it anyhow so I added 6.5 gallons. The fuel gauge is reading about an 8th of a tank. A few weeks ago I pulled the sender and ran it from empty stop to full stop and in between. It made the gauge read correct. So I put the sender back in thinking it was all good to go. I have no faith in this new sender. Has anyone tried this from Speedway.

 

[66Satellite47]

No offence but Mopars do not use a modulator valve like chevys. There is no vacuum on the 727. That is what the kick down linkage is for pump pressure.

Ya, I KNOW, but I read the article referencing disconnecting the vacuum to the trans that was posted.
So what do we believe? The Chev crap?

 

[BeepBeepRR]

Ya, I KNOW, but I read the article referencing disconnecting the vacuum to the trans that was posted.
So what do we believe? The Chev crap?

I guess they assume you are working on a chevy. I went out today and used my vacuum pump and put 20hg on the booster and then went into the car and hit the brakes and it didnt make any difference. The only thing it did was release the vacuum.

 

[66Satellite47]

I always take the magazine articles with a grain of salt. Too many are Chev guys that don't know there is a difference.

 

[66Satellite47]

I'm don't know nearly enough about this, my guess is this is related to the brake apply rod/linkage for the booster. There are several threads on here about that and folks to ask.