[vinniekq2]

It was using humour to state the importance of the master cylinder. The CofG is similar to the brak proportioning idea.No,master cylinders are not a universal swap. Talk to your local GM dealer that has an old parts guy that hates computers. The piston inside the proportioning valve will mount different/have a different bore(this determines pressure} the mechanical leverage of the pedal/The booster.NOTE: some masters can be used without a booster. Boosters need engine vacuum to operate,big cams do not produce as much vacuum at low speed.Its a very big math formula,k.i.s.s. or really investigate options.Thats why I said research wilwood. Wilwood offers over size rotors/drilled rotors,masters of many types, multi caliper styles(single piston,multi piston,apposed piston) NOTE: with over sized rotors you may need special wheels,,,,

[vinniekq2]

The piston inside the proportioning valve will mount different/have a different bore
oops
different masters have different bores and pistons,,
different cars have different size mounts though a lot are the same,,
I should proof read first,sorry

[69 widetrack]

If I'm correct, your using a the front discs off a 79 camaro and a Trans Am diff with disc brakes? What year of a Trans Am?

I'm going to check it out and get back to you.

[69 widetrack]

OK Carlos, when you add disc brakes to the rear you must use a true 4 wheel disc master cylinder. The pressure and volume requirements to the rear are much greater than that required by drums, disc brakes require more pressure and volume. A four wheel disc master will have a longer stroke and will provide more pressure to the rear disc brakes. So in saying all this, using the master cylinder and brake booster from the Trans Am should solve your braking issues.

[cobalt327]

Is the '95 T/A rearend a 7.5"/7.625"? If you have a Ford rear end in it now, it might be a good piece. Disc brake kits are available for the good Ford rearends. Just saying. You can ID the rearend here.

BTW the intake is a Performer RPM. Different than the 'standard' Performer, the RPM is biased towards more top end and is a bit taller than the Performer.

To find out what size the carb is, use the number from the driver side front of the choke tower of the carb to look up what CFM it is. Example of the carb number below:

[PRHeloPilot]

Vinnie - I know is was humor. I just tried to look like I know at least about helicopters since this car restoring stuff is trying to kick my butt.


Ray - The front "I was told" is from a '79 Camaro. I'm confirming everything as I go. I want to use the rear from the '95 TransAm can't use the brake system because it's ABS and has electrical wires coming in and out of it which I suppose means some kind of computer somewhere. I decided the if I can avoid it the only thing computerized I want in my truck is my electronic ignition and my music radio.

I went and found out that a 1979 Corvette has 4 wheel disc brakes and the master cylinder can be purchased in stock at O'Reilly's in the CARDONE brand for only $17.99

Cardone Remanufactured 10-1749 - Master Cylinder | O'Reilly Auto Parts


At Autozone I can special order the FENCO brand for the same price

http://www.autozone.com/autozone/par...ier=23325_0_0_


and finally they sell the CARDONE also at Summit Racing:

A1 Cardone Remanufactured Master Cylinders 100-101749 - SummitRacing.com


If you can confirm that this will do what I need AND if I find tomorrow that it mates well with my booster, I'll buy it and then I'll have put that issue to rest and can move on to the next headache, I mean issue to resolve, as I enjoy this rebuild If it doesn't mate with my booster I'll start another search to find a car that has 4 disc brakes and has a master cylinder I can get locally at a reasonable (not race car part) price. I figure brakes are too important to go buy used at the junk yard where I might then have to rebuild it so I'll just buy it at the store but I want to get it local to make sure it fits my booster.



Cobalt - I couldn't find any stamp other than HOLLEY and the numbers I took pictures of here. Hope this helps determine what carb I have. Regarding the Ford rear since I've come across so many shortcuts in the way this thing was built and they had told me it was also a Camaro rear, there's no way I can trust this rear to be reliable and at least with the TransAm rear I know what I have and can get parts when needed.

[69 widetrack]

Sorry it took so long to get back to you but I had a meeting that went a little longer than originally thought.

Now your brake situation.

Use a Raybestos MC #39052 (you can get your local parts store to cross this number over to Cardone or Fenco part numbers) and a disc/ disc prop valve on a stock 79 Camaro disc/drum booster. This master is spec'd for a 1980 Corvette not 79, it may cross to the same number. It works and is cost effective.

The proportioning valve used is a PV-4. Check out a valve at your parts store and see if you already have one on your truck(I know you said you weren't sure anymore if it was 79 Camaro). If you have trouble with the PV-4 number working at your parts store let me know and I'll see if I can cross it over.

This should work for you and happy braking.

Let me know how it all works out.

Best Of Luck
Ray

[PRHeloPilot]

Originally Posted by 69 widetrack

Sorry it took so long to get back to you but I had a meeting that went a little longer than originally thought.

Now your brake situation.

Use a Raybestos MC #39052 (you can get your local parts store to cross this number over to Cardone or Fenco part numbers) and a disc/ disc prop valve on a stock 79 Camaro disc/drum booster. This master is spec'd for a 1980 Corvette not 79, it may cross to the same number. It works and is cost effective.

The proportioning valve used is a PV-4. Check out a valve at your parts store and see if you already have one on your truck(I know you said you weren't sure anymore if it was 79 Camaro). If you have trouble with the PV-4 number working at your parts store let me know and I'll see if I can cross it over.

This should work for you and happy braking.

Let me know how it all works out.

Best Of Luck
Ray

Are you kidding me? No need to apologize for anything. I'm so grateful for everyone's help here it's not even funny !!

I looked up the Raybestos MC #39052 and JC Whitney has it for the 1980 Corvette. They also have the Cardone for the same car and it's the same part# as the one I previously found for the '79 Corvette so I'm in luck because O'Reilly's website says they have it in stock in all of their stores around here. It must be a popular MC.

Found the PV-4 here. Haven't found it anywhere local but I'll keep searching

74-96 Chevy/GMC Workhorse "P" 1 Ton JF9 Type Van Front Disc/ Rear Disc Proportioning Valve at Carolina Classic Trucks


.

[cobalt327]

Originally Posted by PRHeloPilot

Cobalt - I couldn't find any stamp other than HOLLEY and the numbers I took pictures of here. Hope this helps determine what carb I have.

Are you sure there's no list number located in the general area of the red circle below? The number should be 3310 (based on the 6R 6931 casting number) followed by a "dash" number. In your case this would be -2 or higher. The dash number is for showing changes or revisions to the basic carb.

Other things about the carb:

Has vacuum secondaries, it's a 'dual feed' w/center pivot floats and has what's called 'cathedral' float bowls, it's a model 4160 w/a 'squarebore' bolt pattern (as opposed to a spreadbore, like the Quadrajet carb uses. The factory specs are in the link above.

Regarding the Ford rear since I've come across so many shortcuts in the way this thing was built and they had told me it was also a Camaro rear, there's no way I can trust this rear to be reliable and at least with the TransAm rear I know what I have and can get parts when needed.

Just wondering if you have researched the new rearend. You can get parts for it, sure. You can get the same parts for a Ford rearend and the chances are good to excellent the Ford rearend will be a stronger unit to boot. About the only thing the T/A rearend has going for it is disc brakes. But if you have made up your mind to use the 7.625" rearend, then so be it.

[PRHeloPilot]

Only numbers on that carb are the ones I posted in those pictures. I looked everywhere on it with a strong flashlight to be absolutely sure. I'm telling you this truck was half-assed put together and nothing makes sense. The only good thing is that when I'm done with it I'll know so much about it that I'm going to keep it forever.

My mechanic also looked at the rear. The only way we know its a Ford is because it's stamped on it but there aren't any other numbers either. It also doesn't have a tag attached like other Ford rears. Based on the pictures of the link you posted my best guess is that it's a 8.8" rear end. It looks exactly the same on the back and it has 10 bolts.


This thing is a total mystery and that's why I'm exchanging parts on it that I know where they come from. The T/A rear also has emergency brake system already. If I kept the Ford I have to add discs and emergency brakes and I still don't know its condition. That alone makes it easier to buy the new MC and valve, specially when I already bought the donor T/A.

[cobalt327]

I forgot to say if the carb is a 3310, that would make it 750 cfm.

[PRHeloPilot]

I went to Holley.com and noticed that most all street performance carbs are model 4150. So I was reading the FAQ and it said something about the choke tower. I went out to the hangar and checked and you were right, there it was stamped on the side on the choke tower. I don't know how I missed it. Mine turned out to be a 4160 (3310-4).

[cobalt327]

Originally Posted by PRHeloPilot

I went to Holley.com and noticed that most all street performance carbs are model 4150. So I was reading the FAQ and it said something about the choke tower. I went out to the hangar and checked and you were right, there it was stamped on the side on the choke tower. I don't know how I missed it. Mine turned out to be a 4160 (3310-4).

There you go! That's a good carb, BTW. It's quite flexible, it compliments the RPM intake and is all the carb you'll prolly ever need for a street driven SBC.

A 4150 is easier to tune because it has a secondary metering block instead of a metering plate. The block means it'll have replaceable secondary jets. You can convert your 4160 to a 4150 by using Holley p/n 34-13 should you ever want to do so. You'll need a longer dual feed fuel line, too.

[cobalt327]

Originally Posted by PRHeloPilot

Are you kidding me? No need to apologize for anything. I'm so grateful for everyone's help here it's not even funny !!

I looked up the Raybestos MC #39052 and JC Whitney has it for the 1980 Corvette. They also have the Cardone for the same car and it's the same part# as the one I previously found for the '79 Corvette so I'm in luck because O'Reilly's website says they have it in stock in all of their stores around here. It must be a popular MC.

Found the PV-4 here. Haven't found it anywhere local but I'll keep searching

74-96 Chevy/GMC Workhorse "P" 1 Ton JF9 Type Van Front Disc/ Rear Disc Proportioning Valve at Carolina Classic Trucks


.

Because the stock type combo valves are not adjustable, finding a combo valve w/the right front-to-rear brake bias to match what your truck needs might not be so easy.

So what you might want to consider doing is disabling the combo valve's proportioning function then adding an adjustable proportioning valve.

The reason for disabling the combo valve's prop. valve is because if you just add an adjustable proportioning valve to the existing combo valve, you would in effect be adding a prop valve to a prop valve.

That means you would not be able to increase the rear brake pressure beyond where the combo valve is set to. You would only be able to take more pressure away from the rear brakes.

Fortunately on most GM combo valves, you can disable the combo valve's prop valve by unscrewing the fitting from the combo valve that has the rear brake line coming from it, then remove the (rubber or spring loaded metal) valve inside the body, then reattach the fitting.

Then you would add an adjustable prop valve.

[PRHeloPilot]

I read about that during my research yesterday. It was one of the questions I was going to ask if I wasn't able to do it today. Thanks for the tip.