I'm in the same boat as "catdad49", a GMC needs PONTIAC power,tri-power, dual quads, single 4 bbl. That's all I'm saying. Your truck, your money. Mitch
You missed something- that's a 6 cyl Funk Conversion Ford 8N tractor right beside it. And I agree, kinda rare truck in great original condition- deserves better than a belly button engine, leave the big Six
Ya asked my opinion. So here ya go. Dropped axle from Nostalgia Sids Rebuild the brakes Hop up the 6. Add a 5spd or old Saginaw with OD 355 rear gears. New bias tires enjoy the crap out of it.
You DID ask for opinions! I don't know WHICH GMC six you have, nor do I have a cylinder head intake pattern for the GMC sixes. If it were a Chevy six, then it would have three pairs of two intake ports. So a dual carb intake may be eye candy, but maybe not as efficient as a single carb! If the GMC six has a similar cylinder head intake pattern, AND THE SET-UP DOES NOT PHYSICALLY INTERFERE, then a triple set-up gives both eye candy AND performance. Don't even think about even considering the possibility of progressive linkage. Do your homework, and pick three SMALLER carburetors, and use solid linkage. An overdrive transmission would allow a higher cruising speed at a reasonable RPM. A modern 5-speed might be easier, but keeping it old school, I would at least investigate an older transmission with overdrive. I would leave the six, or if you want a bigger engine, then a bigger six. If you must have a V-8, remember that a dual quad will out-perform a single quad will definitely out-perform tri-power. With ANY aftermarket intake/carb set-up will run as well (or as poorly) as your homework/research. Check the second line in my signature block. Jon.
What period is "period correct", in your mind? Things were changing quickly when that truck was in use....for example, they completely redesigned the trucks half way through the 55 model year....and introduced Pontiac V8 power. And the Pontiac cars were getting bigger engines almost every year in the late 50s. It would be a downgrade to drop a Chevy V8 into the truck. Think Pontiac, Olds, Cadillac, etc. But, if you stick with a Chevy, again you need to figure out what period you want. Mid 50s guys were putting Strombergs on everything, then they moved to the small 4bbls (one or two), then in the 60s they started using larger single 4bbls. So, answering your question requires more info.
From a finacial point of veiw, DON'I MESS WITH IT. As a rare original "10K mile survivor", it's probably in the $20K value range in today's crazy market. Once you start major changes (engine, trans rear, brakes etc) it is no longer a survivor, but becomes just another nice old truck with a cool story...they're only a survivor once. So as @panhead_pete points out, you could spend as much as $10K on all the modifications...and after you've spent that $10K on it, you'll end up with a nice old upgraded (non-survivor) $20K truck.
If it is indeed an unmolested survivor, I'd have a hard time changing it. Fix what needs fixing and drive it. If you still feel the need for speed and more hp, find another and build it like you want, they made thousands of them so it shouldn't be too hard to find another to build. Nothing wrong with leaving one like it came from the factory.
As far as an investment/return. The highest profit margin is cleaned up, fully functional as is. But I got a day job so I’d rather enjoy. To enjoy that truck daily, a gear change would be the only mod needed. For a period “hot rod” the 6 would work. But ……check these out https://droppedaxles.com/photo-album
One word of advice. If you do decide to gut it for a sbc keep the the original running gear. The next owner, if you ever sell it may want to restore it to it's former glory. I'm a Ford guy also, but that is nice pickup.
The funny thing about most "period correct" vehicles is that they usually have concessions to later technology often hidden though sometimes not hidden. No matter what engine you select, I think one of the first choices you need to make is the transmission. Whether its a manual or an automatic it needs to be an overdrive if you want to drive and enjoy the vehicle a lot. Chevy wise, you can put a lot of effort in using a "period correct" version, but by the time you see it all thru there will be small things that are difficult or expensive. There are books like the one pictured below that will help you with finding and selecting the correct parts. The thing is, most people don't know all the little details that distinguish original items from the later versions. Take the "double hump" Chevy heads. How many billions of cycles have a used set gone thru? How many times has it been decked or had the valves reseated? Are they even usable at this point? I believe I read somewhere that an aftermarket head manufacturer was making better flowing versions with a double hump cast in them. 350 Chevys weren't available in 65, but then 65 is an arbitrary date set by the Hamb.....not everyone considers it one of the ten commandments. Lots of room for opinions as to what is/isn't acceptable for period correctness. Will your A/C have R-12 freon or will you even have an A/C ? My recommendation is to follow a general theme of Nostalgia and build something that is enjoyable to drive........... Here is some information that may prove helpful in purchasing/tuning a tri-power set-up. Ok, that should help a little. Looks like you have a great project to build............Good Luck Edit: 3 x 2s on a 383 is a lot more enjoyable than 3 x 2s on 283............
I am doing a 51 GMC. It will be my daily so instead of doing some crazy induction or going the LS route I am building a nice small block and decking it out to look like it was just pulled out of a 56 Chevy. Even so far as using the 2bbl and intake off my dads 56 Chevy and repurposing the original Jimmy 6 air cleaner. The front wheels are 56 Chevy and the rears also reused 56 Chevy centers that I mated to new 10" hoops.
Offy 4 deuce intake with Rochesters. One of my favorites. There are several Offy dealers on the HAMB give @mctim64 a call at Hanford Auto
Hopefully working on my 49 GMC this summer. Picked up a 283 years ago but think I’ll keep the 6. I friend has a dual carb set up I can use and I have a 5spd. Already have a rear with 355 gears with the 6 lug. The M2 set up will probably stay on the shelf. A stretched axle sounds fun. The local scrap yard has a 54 Chevy belair. I might get the brakes and 5 lug rear
Nice truck!Dress up the motor thats in it with dual carbs,header. Nothing more traditional than that.
I forgot, I have a similar dual quad setup I need to get into the classifieds! The cabs turned out to be something special so it would be best for me to just get rid of the intake alone. What intake is the tripower one?
Well for a v8 with period pieces. A v8 bell from 55–71ish truck ( I think that far up) 3 speed will have the mounting ears like your current bell. A straight 6 bell will work but needs to be 63 -72 ish. Your stock trans should bolt up. Saving fab and linkage work. Keeps ya from messing with the drive shaft. Better gears can be bought for the stock rear. Exhaust manifold clearance is tight on the drivers side. Look at 55-56 Chevy car manifolds. For 3 deuces, those are easy to locate. Speedway should have carb bases for the outtside carbs to ease the setup
Clean it up, go through the brakes, suspension, steering and call it done. Those are great reliable trucks and with 10k miles on it it shouldn't need any engine work other than oil change, plugs, points, etc. When I was a kid one off my buddies had a similar Chevy pickup. We used it as a tow vehicle, camping trips and it just kept on running. Got decent mileage and never let us down. The saying that they are only original once is true, don't mess with it.
That truck is what everyone and their dog is looking for....the holy grail. Ultra low mileage original.....with real patina and old door graphics. Some rich old Ralph Lauren type fart, with a ranch outside of Aspen or Telluride, would be on that truck like a duck on a June bug. As already stated but bears repeating, whatever you end up doing, I would keep and store every nut, bolt and part taken off of it. Great truck, good luck with it.
If going small block, maybe an early Vette fuel injection , Vette valve covers and a pair of ram horn manifolds. I am partial to inliners so maybe split manifolds and multiple 1 barrel carbs .
Yeah, I just grabbed the first random image. It doesn't even look like the SBC one that I actually had. But you get the point. Lets just call it a "stock photo" Although, now that I think of it, Offy uses the same casting for both, they just drill whichever bolt pattern they need. TONS of hand machining on their stuff. Great vids on IG
I'm with those in favor of keeping the six. Dare to be different! Everybody and their cousin does the V8 thing
^^^^^^Anthony hit the nail on the head with the above^^^^^^ Seems a perfect formula for a fun truck.....not just another truck. Lynn
Be careful what you do. You could be taking an original unique and rare GMC truck with 10,000 miles on it that has survived all these years that may be worth as much as $20K and turning it into a nice $10K modified truck.
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