503 engine

[C10 - C90 Bill]

Originally Posted by 66Submarine

The 22.5" was/is the tubeless equivalent to 20" tube type.

OK, there is my limited wheel knowledge showing, lol.

Especially with the newer stuff...

Edit: Just did a little research on the subject and there is a lot out there !!

Bill

[Firefool]

Drove truck home from shop sunday, it ran well, stopped good. First time its moved itself in who knows how long. Should be a soild rig, just need to do a ton of cleaning on it.

[bob_o]

Very cool. Thanks for bringing this old beast back from the dead!

[Mr Chevorlet]

Very nice, That was a big motor, glad i looked at your thread. Love the old fire trucks

[Firefool]

Guys I have been driving the truck and it is doing great, I did put some 22.5 radial tires on it....... any one have a interest in the 9X20 Tube type split rings? Tires are dry but have alot of tread on them be great for a farm or grain truck.

[_Ogre]

nice save on the 503 motor
i like the oddball stuff
that push rod is humongous

[edpruss]

Originally Posted by Firefool

Ok heavy haulers,

My 503 has all the machine work complete, all parts are at my shop even new .060 over pistons. Do any of you guys have or know where I can find torque specs for this engine. Any help would be great not sure how picky they are heck the rod studs/nuts are cotter pinned.

Thank you

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[edpruss]

I just got a 503 with 26M miles on it, do you know if there any high compression(propane) Pistons available for them?

Come across any spare water pumps?

Thanks, Ed
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[56_firetruck]

I have a 56 GMC 630 that was a tanker firetruck and I'm needing a few parts can anyone guide me in a direction? I'm needing brakes and I have a few questions

[55 gmc 630]

Did you find any parts/info you needed? I Just acquired and old 55 gmc 630 w/the 503 and am just learning about it's bits.

[56_firetruck]

No I haven't found anything yet. Can you get some pictures of the Driveshaft I'm having to make one from scratch and I need some guidance?

[55 gmc 630]

[IMG][/IMG]I can... tomorrow. I am not familiar at all with how these forums work... like how to upload pics but I will attempt it. Mine is a 5spd manual with a "brownie box" right behind it(20 speeds) so my set-up may be different than yours- like if you have 2spd rear. I might be interested in any pics of vacuum lines related to the governor. I will see if i can add an image w/this post just as test---oh, asks for url... i have to figure that one out. more later

[56_firetruck]

I don't know how to add pictures either or I'd add about 10 any help?

[C10 - C90 Bill]

Originally Posted by 56_firetruck

I don't know how to add pictures either or I'd add about 10 any help?

I'm sure no expert at it and after all these years, I was able to finally post one the other day, but I did it with the help of the instructions we have here at Site Feedback and Announcements:

http://67-72chevytrucks.com/vboard/s...d.php?t=627506

[55 gmc 630]

I have uploaded pics to my album--- it's the only album i have on here... as far as I know it it public. Let me know if you can't access it or find it or...

[56_firetruck]

How big is the u-joints they don't look the same as mine mine are 5inches out so to outside

[55 gmc 630]

5 5/16"... not counting the plates that are under the bolt heads

[MFD 56Gmc]

Great thread! I'm new here and also looking for some resources for the 503. My fire dept has a 56 GMC 630 that we are looking to restore. Are there any resources out there for parts?
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[55 gmc 630]

I the guy who started the thread certainly managed to locate parts to rebuild and engine but beyond that I have not seen a whole lot. Mine has under 30k original and I am hoping it never needs opening up. I would like to understand the carb better and to know how the original governor system was hooked up- mine seem to be unplumbed. Along those lines...there are various holes/ports on distributor I would like to know what they are all for too. Yes, let's keep in touch regarding our trucks . I will try and add pics to my album of the carb I have on mine.

[MFD 56Gmc]

Ours has 20K miles and runs well. It leaks a ton of oil though when sitting. I'm sure it needs an oil pan gasket amount other things. It's only used as a parade truck these days so it comes out only a couple of times a year. What we have been having problems with are things like brakes, electrical issues etc. We have been talking about restoring the truck, but cant find anyone that wants to touch it. A thought by out district was to yank the motor and trans and install a modern crate motor. I feel it's a shame to do that, so I'm trying to find some resources to freshen up what we have and to make it a little more reliable. I am a boat mechanic by trade so with the right resources I know I could tackle this myself.

[C10 - C90 Bill]

If no one jumps in here also check with some of the guys at Stovebolt.com, the ATHS site as well as Just Old Trucks. There are a lot of old time mechanics on those sites and they could probably help with parts too.

[cff]

I have a 54 630 with a 503 and 15000 miles. It was a tanker fire truck and I have taken the tank out. The driveshaft has a pretty cool mechanical disc brake setup for the emergency brake but the disc is mounted to the main fire water pump. When I took the pump out I'm not sure how to mount the disc for the emergency brake. Has anyone done this. I don't want to leave the pump in for a number of reasons. One - the pump sticks up above the frame rails, so I would have to raise the bed floor. Two - I don't want to have to keep maintaining the pump. Three - It's heavy. I don't want any extra weight.
Thanks in advance for any ideas.

[55 gmc 630]

My '55 , as i am told, was a fire truck tanker also... but now has a flatbed. Mine has the break thing on the driveshaft no pump remains so not sure of that set-up. I have not run truck much---got it trailered here(drove it on and off) and it's been sitting 2 months so not real familiar with it other than plugs and wires and such. Mine has a 5spd w/4 spd brownie box. Look in my photo folder- there are a bunch of pics i took for guy with driveshaft questions- see if you get any answers from them. I would have to look more closely at my set-up to tell you anything. I'd love to see pics of the pump you speak of and controls. https://www.youtube.com/watch?v=igIPSk0qqCQ . https://www.youtube.com/watch?v=1ng3QHwOAik

[1956630]

It's been some time since I've been on the site, I could not figure out how to sign in so I have a new user name. However things have gotten crazy in life I'm considering selling my GMC 630. Where do you guys recommend trying to sell a unit like this? Only would allow it to go to a good home it's just too cool and clean to see it tore up.

Thanks Joe

[cff]

Hey Joe. I might be interested in your GMC 630. Can you send me some pics? PM me and I can send you my email address or phone number to text me. Thanks, Ron.