Need help 1967 Chevy c20 250 inline 6 all original project. Just want reliable truck.

[Justin1983]

Hello everyone I'm 36 years old and don't know much about these older style trucks but I have done alot of research. What I have is a 67 inline 6 with all original everything, it's my dad's truck that my grandpa bought new. It has 80,000 original miles on it. The carb as never been worked on it starts and runs but it's coughing and backfire like crazy. Stalls not to reliable. What I want to do is put a new offenhauser intake mainfold with hedman headers with a Holly 390 , just wanna use this truck for fishing and camping and hauling wood got the 4 speed manual transmission. I don't know if I'm going about it right. I understand bits and pieces. But I'm gonna need alot of advise from YOU the ppl that know best. I understand the intake manifold needs a heat source being I live in Minnesota. And I found a $30 plate they sell for it.All fine stuff like materials I need I don't quite know yet. I wish there was a list of the things I needded to have to get the job done RIGHT not half assed . Like the gaskets , do u use separate gaskets for the headers and mainfold ? Stuff like that. Or the studs for the headers.. clearance of the carb.Not going for show or speed. Just wanna reliable truck that sounds bad ass and runs like a top. Wanna start ordering parts Sunday and get the ball rolling. Step by step detailed help would be very much appreciated. Let me know ur thoughts as I do spend alot of time trying to find these ansey

[Canuckvetter]

Welcome to the forum!

[68bowtie]

First of all welcome. Sounds like a really great truck, and part of the family that's cool. We all love pictures...

There is a great search feature on the site, you should be able to come up with great info to all your questions.

[MARKDTN]

Just curious why you would want to change the intake on a bone stock motor? Headers on a stock I6 motor are a pain to install, and add very little. To me, I would fix what you have and go another 50 years. Good luck whatever you decide, sounds like a cool truck.

[geezer#99]

Welcome!
Yup, pics would be nice.
If you want to do it right why are you throwing parts at it?
If you can’t get the original stuff running, how do you expect to get new stuff to work.
Most of the time it’s not just bolt it on and go. It usually requires some tinkering!
You need to learn the basics first and then upgrade.
Let’s see what you got!

[Justin1983]

The carb is 50 years old. Cant find a new stock intake manifold. The exhaust manifold is leaking. It starts right up and putts along. Thanks guys.

[clay68c10]

Sounds like a nice project, and it’s cool that it’s been in the family the whole time.
I would rebuild the carb and reseal the intake and exhaust manifolds. Do a full ignition tuneup and then see where you are at. Keep it simple and cheap.
Any pics??

[bill3rail]

Keep it stock and rebuild what you have.

If you want badass sound and reliability then drop in a modern LS engine with headers.

My 70 L6 is extremely reliable as it is. Remember, these trucks were designed as a tool, not for bad assness.

If you are dead set on doing all you mentioned but do not have life experience on building bad ass trucks, your wallet would need to be real deep as you will be paying someone for assistance. I would hate to see this project get dropped due to frustration and end up behind the garage rotting away. KISS, Keep It Simple Silly! They are reliable the way they are.

Bill

[Justin1983]

I'm not dead set but like I said I can't find stock parts to replace the old ones. Summit racing has the carb , and stock exhaust manifold but only intake available is the offenhauser, and with that u wouldn't be able to use the stock carb....

[palallin]

Maybe I'm missing it, but why do you need to replace the intake manifold?

[geezer#99]

Originally Posted by Justin1983

I'm not dead set but like I said I can't find stock parts to replace the old ones. Summit racing has the carb , and stock exhaust manifold but only intake available is the offenhauser, and with that u wouldn't be able to use the stock carb....

Sure you can!
With an adaptor.

[Justin1983]

Also a new stock exhaust manifold is the same price as the hedman, also I read everywhere how restricted the stock intake is.. I just thought a new modern setup would have been the best bet now u guys got me thinking. Just what I wanted.

[geezer#99]

Take some pics!
Your best bang for the buck on a stock motor is an hei distributor swap.
Then learn how to rebuild your carb and fine tune the motor.

[jfnar]

You can probably find a used intake manifold on the parts forum but an offenhauser intake will work great with a stock exhaust manifold and you don't have to worry about plumbing in the heat. That's what I have on my 292. Keep in mind that you can use an intake manifold from 196, 230, 250, or 292. They're all the same. One upgrade I would recommend after you sort out your carb and manifold issues is electronic ignition if you don't already have it. Pretty simple upgrade. You can also check out Stovebolt.com and Inlinersinternational.org for more info on these engines.

[Justin1983]

That is part of my plan also , so what I'm thinking is getting a new stock exhaust manifold , order rebuilt carb keep stock mainfold and put in a hei

[Justin1983]

Jfnar what carb then?

[jfnar]

I understand that there's a 292 exhaust manifold for the bigger trucks that has 3 bolt flange rather than 2 bolt that's a little larger and less restrictive. If you can find one of those it might be worthwhile. One point I missed in my earlier post is that there are some 250s with integrated one piece head / manifolds. Nothing on those will work for you unless you change the head too. I'd recommend just avoiding those.

[jfnar]

On my 292 I used the holly 390 cfm 4 bbl. It seems to be working pretty good. I get 17-18 mpg which isn't bad for a 292. But I also have an OD transmission.

[jfnar]

Another good option is a 350 cfm 2 bbl. It will work on the offenhauser manifold too with an adapter.

[Justin1983]

Wondering if this part has the heat flap in it https://www.rockauto.com/en/catalog/...+manifold,5860

[Ozark Tim]

https://springfieldil.craigslist.org...836238911.html

hope that worked. I just posted a link to what you need
Keep it stock! You may need a little machining work and your carb can be professionally rebuilt. I agree on the ignition comment also. Have the distributor checked out, make sure bearings are good so your dwell isn't jumping all over the place

[54blackhornet]

I would suggest you keep your grandfathers pickup original. The 250 is a very well designed engine and a descendant of the engines that practically built the Chevrolet brand. Anything you need is easily available. Both the intake and exhaust manifolds can be machined at your local NAPA or similar location, they can true the mounting surfaces and replace any broken studs. Carb rebuild and GM HEI install along with 8mm wires will get you one sweet running engine. Remember your grandfather is watching you !

[Justin1983]

54blackhornet thanks for that comment that what I'm going to do the exhaust manifold is shot thinking of getting this one from Rock Auto https://www.rockauto.com/en/catalog/...+manifold,5860 and bringing this into local shop and have the pro get it done right thanks for everything guys seems like everyone got the same message fix whats wrong and keep orginal and that's what I'm gonna do anyone have the link for the hei gm distributor thanks again

[Justin1983]

What do u guys think of replacing the gas tank to make sure everything is clean? Or is that all BS?

[Steeveedee]

You can drain it and take it to a radiator shop for a flush if there's a lot of guck in it. Then seal it. You can find sealers at different places on line. You may not need to do anything. Just siphon some gas out to see what it looks like before you wild on a gas tank.