The Stovebolt Site Forums Welcome! Welcome Centre Do It Yourself (DITY) Gallery 1949 GMC 3/4-ton ... "Daily Driver and then Some"

1949 GMC 3/4 ton
4 speed with 4.57 gear

This truck has been restored to stock components. It's also now my daily driver and shop truck. It has 79,000 original miles and completely rust free. I just didn't have the heart to change much.

Anyway, have owned and restored many muscle cars. I am owner of a motorcycle shop in Georgia (Baxter's Garage). Our specialty is high end customs, blueprinted engines, and EFI tuning but we also restore bikes as well. With a complete machine shop and sheetmetal fab shop at my disposal, it's hard not to go at this ol' girl with a long list of upgrades ... but I've refrained. LOL.

My very first post was in Driveline in regards to fluids. Here's what I came up with:

Engine SAE 30, Trans GL1 Mineral 90 weight, Diff GL4 non syth 80W90, shock oil 10 weight.

My next post was in General Truck Talk about the bias plys and stock wheels. That quest ended and led me to completely go thru the mechanicals and use this ole girl as a daily driver. So...its now a 270 with a 4.10 rear gear and she purrs at 3000rpm at 65mph. I was able to find a 302 which I will be rebuilding with period correct hot rod parts, install it, and drop to most likely a 3.08 or 3.55 rear gear. I've got a Project Journal started with videos of the GMC 302 complete rebuild. Current mods will get me thru until then.

Back to the wheels. I had Detroit Steel Wheel make up a set of raw 18x8, 8 lug, 3.5 inch backspace wheels. I painted and striped them, installed clips and caps, and tossed on a set of 235/60/18 tires.

On top of that, the drivers side of the I beam was beat up a bit and an oversize king pin simply wasn't big enough so I machined the hole, made up a bushing, reamed to size, all new brakes and hardware on all 4 corners, replaced the single reservoir mast cylinder with a dual out of a 67-69 Camaro, plumbed it in, and good to go.

To finish up for now, shot some paint on the grille and running boards, refinished the bed, made the side wood, lettered everything up for my shop, and done ... until the 302 gets finished anyway.

Great forum guys. Here are a few pics, including the 302 "before" shots.

Thanks for your info.

Great looking truck, congrats

A few more pics....was even able to find an original plate in decent shape and restored it...not a repop.

Thank you very much sir!

Nice job and its a great looking truck.

Thank you very much sir.

WOW!!! And just up the road from me (kinda)

PS: Love the Indian, an old Russian I worked for had a 41 Chief with Bosch electrics.

Thanks. It's an original 48 with only 137 miles on it. Did a complete mechanical restoration and she runs great. If you're ever in the area, feel free to come by the shop. I'll give ya the nickel tour.

Thanks for the heads up. I know a bit of power can be had by a bump in compression and lightening up the pistons. I design all my own pistons for my engines. I'll probably do the same here...a set of forged and have KB make em for me. I know I'll be boring the block as well...I understand up to around .060 over is easily attainable. Shooting for a min of 300hp and 400ft lbs torque out of the build.

I see you are in Ontario. Have friends in the Kingston area, have judged the bike show in Toronto a few times, have other friends in Shallow Lake, Guelph, Sombra, Port Lambdon, and the area. Great up there.

I am in Thunder Bay northern Ontario quite aways away but close to Minnesota’s border.

Oh come on now, Ontario isn that big! Yeesh. I drove back out west from Toronto once and let me tell you: “Western Ontario is gorgeous! But man oh man, it’s disheartening when you leave a major town/ city and see the next road sign saying: “Thunder Bay: 750km” ....ugh! Is your fuel good? 😎

From Thunder Bay to Sault St Marie, 8 hours. Sault St Marie to Toronto, 8 hours.

Beautiful truck. They do make great daily drivers in nice weather. I drive my 49 as often as possible.

I chuckle...most Americans see provinces as states in size. No...Ontario is bigger than Rhode island. haha

Oh come on now fellas, Mercator maps don’t lie... of course Alaska is 5 times bigger than Brazil and Antarctica is bigger than most of all the continents put together!

Very nice truck by the way!

Thank you so much. I have a couple small things to deal with...still wanders a bit on rough roads. If the road is decent, its absolutely new car smooth as butter. Brakes are great. I did tighten ball and sockets on all tie rods, etc...so steering is jam up...but, the steering gear box needs a slight adjustment...just enough to tighten up about 1/8 turn of slop. I also may try a 15 weight shock oil. I'm having westach make me a custom tach to match the factory gauges and will mount on the column. A necessary item in my book. Also, need to install a speedo calibrator. Other than that, get the 302 built.

I actually wanna get the incorrect Rochester B off and put the proper Zenith back on it. I need the 11442 with 32mm venturi. Not having much luck. A couple other ideas...a Carter AFB or grab a Mikuni or Keihin CV carb off my shelf, make an adapter, and bolt one of those on. The B is just too small. She pops occasionally and sucks the fuel. If anyone has a Zenith or other suggestions I'm all ears. Still toying with the EFI idea too. That would be the cats meow really. Bit strange as it may sound, I enjoy using a chole amd throttle knob.

Here is a cross reference - scroll down to GMC and note several other Zenith model number carbs for 270's.

https://www.carburetion.com/industrial/zenithcrossref.asp

Holley also has a 270 application - but I am not familiar with the reputation for these Holley's. I have a NOS GMC 270 Holley on a shelf here, but plan to use that as a back up - or just to test it someday when I have nothing better to do.

There is a 2 barrel Stromberg WW carb for the 302 (or even the 270) that might be a good option for you. Would be interesting to read Jon or Jon G opinions about the Stromberg WW (or the Holley for that matter) My impression is they are very good carburetors too. I have one on a 302.

Keep us updated about your 302 rebuild. I would like to follow your progress on that, and I am sure others will too!

Tom,
Thanks for the great info! Being I own a machine shop, I'll be doing everything myself. Valve seats, a little porting work, and updates to the valve train. Have a set of forged pistons made. Balance the crank. May get compression up to around 8-8
5:1. Not sure if I want to fabricate my headers and an aluminum intake or just buy one...several decisions to make there. I have a YouTube channel where I do tech talks, projects, etc. I'll probably post videos there too. Disassembly, headwork, block work, then reassembly and tuning. If you folks would be interested, I'll post progress here.

I'm also considering 3 different directions. either keep it as stock appearing as possible, use all period correct hot rod parts, or go full tilt and modernize with HEI, fuel injection, etc. Cant really decide just yet.

Thanks again for the carb info for the 270.

It's possible to do caster adjustments on ibeam by using shims on the mount plate. You can also get a degree or two by just loosening the bolts and shifting it slightly. Believe it or not, the sequence the bolts are tightened can change it 1 or 2 degrees...which has a huge effect on stability. It's common on heavy duty trucks like the 3/4 ton and up, to put a bit of negative caster in. Going to a more positive caster, the wheel centers itself easier and is a bit more stable. Tough part is finding an alignment shop that will do it. I use an alignment system from eastwood that can nail it. It's not a true 4 wheel alignment but I can at least get toe right and adjust caster a bit. I'll be doing this to mine along with tightening up the gear box slightly...that should remedy or greatly improve the wander on rough roads. As for the stiff ride...its all in the springs. Shocks will dampen but not change how stiff it feels. I'm keeping the stock absorbers on because I can change fluid viscosity. It's currently a 7 weight. I'm going to try a 15. I know itll be stiff, but should slow the rebound down quite a bit hopefully to reduce the bouncing effect.

Finally had a chance to get the 302 on an engine stand.

Actually, not on this engine. I have found a stash of brand new, NOS original Zenith carbs specifically for 270 and 302. I'll install that and run it as is while I rebuild and hop up the 302. I'll be doing that to the 302 though. It's too easy of a mod NOT to do it during a rebuild. Looking forward to getting the carb on the 270 and dialed in. Itll certainly run much better.

Here is one of the carbs I located. Decided to rebuild with new gaskets and to clean out the 60 plus years of oxidation just in case.

Got the Zenith installed...man what a difference. Runs like a champ. Lost just a little punch above half throttle but not surprised going from a venturi that was badly undersized. The low to mid throttle response, smooth running, and much better fuel economy was well worth the little loss above. May do a little tuning on it just to see if that makes a difference. As a side note, if any of you are trying to locate cup grease, or the closest equivalent that exists today (lithium soap/mineral oil) for your distributors, speedo drive, etc...I found this. Can be ordered off Amazon and other places. See pic. Also got the alignment and gear box adjustment done...drives absolutely straight with zero wandering. It's a pleasure to drive now. I'm going to say I'm pretty much done with it as is. Itll be a little while before I have a chance to get the 302 done for it but I'm in no hurry.

Well Done Sir!!!

Thanks for sharing and don't be a stranger.

RonR

Being a stickler for details...it has bothered me that the temp gauge on Shop Truck wasnt reading accurately - way too low. The reason...temp sending units for 70 yr old 6 volt electrical systems and gauges are non existent...or have a completely wrong impedance. So the fix...get the engine to known operating temperature of 170 degrees. In parallel, run 1 wire to gauge and a second wire shorted to ground. In the second wire, stack resistors until the gauge reads 170 (accounting for voltage drop in the 6 volt charging system at idle), then soulder the resistors together. From there, if the engine gets hotter, the sending unit will continue to function normally and taaadaaa....we now have a perfectly celebrated temp gauge at 94ohms worth of 1/4 watt resistors. Pics are just showing my testing with different resistance to narrow down which to use. 2 47 ohms did the trick.

I was gonna go that route because mine was originally a electric sender on my 49 gmc but I ended up just swapping a mechanical guage into my cluster but i used the original weathered looking gauge face so you cant tell. Its surprisingly accurate when comparing the reading on my scantool from the obd2 port.

A custom tach...Westach did this for me.

Very nice, kevinb1450

The tach, very nice. Wonder if Westach assigned a part number to your tach. Care to share price? PM is OK.

Thanks, RonR

He did an awesome job. Completely custom. Chose the 3500 rpm range, 6v and pos ground. Works awesome. I'm hesitant to share what I paid, he may have given me a dealer price. May be best to call him, tell him you saw what he did for me, and get a quote. Thanks for the compliments on it.



I started the tear down of the 302 and uploaded a video on you tube. You guys asked me to update ya, so HERE IS a Project Journal devoted entirely to the 302 rebuild. Have a look if you like. Anxious to hear what you guys think.

The videos are mainly intended for the who aren't familiar at all with these so much of it some of you may already know.