1980 Stepside Build... My first build thread

[ChevDog1]

Not much to report for today. Bled the brakes at all four wheels again - and I think I may still have some air trapped in the system.

Also finally got around to a fun project. The stock exhaust has been driving me nuts. Way too quiet. So, I cut off the muffler and tailpipe, and sectioned it back together to come out under the drivers side step. Now the only thing quieting it down is the cat. I also made a larger exhaust tip from some scrap tubing I had laying around. Here are a couple pics. As so as I can figure it out, I'll post a vid. It sounds much better, but still quiet enough to drive.

[ChevDog1]

And another

[ChevDog1]

Found my next part today at lunch. I needed a factory type air cleaner assembly to try and get this thing to pass smog. Found an original air cleaner at a local wrecking yard for $25. Only problem is that my truck doesn't have the original vari jet carb. The carb was replaced with a rochester 2-jet. So my air cleaner has a rectangular hpole where it mounts to the carb, but I have a round air horn on my carb. Going to have to do some fab work tonight to fit a round peg in a square hole. Looks like I'm going to continue to get good use of the steel left in my original fender!

[ChevDog1]

Here is the air cleaner I modified to fit

[ChevDog1]

So tonight, I installed the air cleaner, as well as a correct 195 deg thermostat (found a 160 in there). Warmed the truck up to full operating temp, and took it for another test run. Still has a major bog off the line, as well as visible black smoke when you stab the throttle. Even fully warmed up, the exhaust smells of raw gas.

Decided to pull the carb off, and tear it down to see what jets are in it. The first thing I discovered was that the PO had made some seriously questionable choices when it came to making an adapter for this carb. Check out the photo. One of the ports in the manifold is mostly covered by the adapter! What possessed this guy to do such a thing?

[ChevDog1]

Here is what the manifold looks like under the adapter

[ChevDog1]

Decided to tear down the carb anyway...

[ChevDog1]

So now I have a decision to make. As I see it, I have a few options:

Rebuild and rejet my existing carb (which is a Rochester 2jet from a 1972 Pontiac 350), and modify or replace my adapter to make it fit better.

Find a stock carb, and rebuild it. Install without adapter (this will require undoing my air cleaner modifications). I will also have to find and install the original throttle linkage which is oriented 90 deg from my current setup.

Install and aftermarket carb, like a Weber ($$) with an adapter (don't yet know if these are even available).

I feel like I just slipped a few steps backward tonight. Do any of you have experience fitting aftermarket carbs to integral head 250's. I am open to any and all suggestions at this point.

[Old School Low]

Very few people would have thought to do this. But for some of us, it's a no brainer. Being cheap (me) leads us to be fabricators. I would be proud of this aircleaner. See where I found metal on last? pg of my build.

[ChevDog1]

I just hope my air cleaner work wasn't wasted effort. If I can't make this carb work, I may have wasted my time

[Low Elco]

I'd just clean up what you have, if the throttle shafts are tight. Get a piece of 3/8 plate and make a proper adapter, and give it a whirl. If it don't work, you ain't out much.

[ChevDog1]

That's what I decided to do, Low Elco. But I'm going to have to make a 2 piece adapter to make it work. 1/2" base drilled to the varajet pattern, with a 1" thick top piece drilled for the 2jet. Has to be 2 piece to clear the throttle linkage with the venturis lined up. I ordered a carb kit, and a set of 42 jets to replace the 56's that were in there. Probably won't have anything to report until all of my parts arrive next week, but keeping my fingers crossed.

[ChevDog1]

Today, I had one of the guys in my shop cut me a couple of chunks of scrap aluminum for my new carb adapter. Made the base out of 1/2" and the top out of 1". The two pieces will bolt together using flathead 5/16" screws. I'll have to buy the screws tomorrow, but here are a few shots of my progress

[ChevDog1]

Here is a shot with the throttle body sitting on it. The linkage is what it had to be two piece.

[ChevDog1]

Close up

[ChevDog1]

And another angle. The bores aren't perfectly aligned yet. I need to get the bolts first, and bolt it together solid so I can blend the parting line between the pieces. Just need to buy a couple new base gaskets, and wait for my carb kit to arrive. I sure hope this carb works after all of this.

[ChevDog1]

I've been out of town since last Saturday, so haven't made any headway. Still waiting on my carb kit from Mikes Carbs. It was listed as shipped on 3/20, and has not arrived yet. Mike didn't give me any way to track it, so I'm dead in the water while I wait. Not sure why USPS is taking over a week to deliver this - mike is only about a 2 hour drive from my house. Shouldn't take more than 2-3 days.

When I got home this afternoon, I managed to get the two parts of the adapter blended, and mounted to the intake. All I need is a rebuilt carb, and I can test it out again!

[Low Elco]

Nice tight work! Do you own a machine shop/fab shop? Hope it works out, that's a much better adaptor.

[ChevDog1]

I work for a steel fabrication shop. One of the guys used our CBC plasma table to cut out the basic shapes for me. The rest I did myself with a die grinder, angle grinder, and a drill press. Now the carb bores line up with the manifold, and last night I mocked up the pieces of the carb to see if the air cleaner will still fit - looks good so far!

Just need my carb kit and jets...

[Low Elco]

Lucky dog. Man, I miss my big fab stuff I had free access to back in the day.

[BADAZ chevy guy]

On the first page it looks like you moved the rear springs closer to the frame.

[ChevDog1]

The rear springs are in their stock locations, with original hangers, shackles, etc. I just flipped the axle to the top of the springs.

I called Mike this morning, and found that he had forgotten to ship my order! He is sending it out priority this morning, so I hope to have it by tomorrow, but it probably won't show until Monday.

In the meantime, I'm going to get started on the exhaust. I don't think that there is any way the ancient stock pellet type converter is going to get me thru smog, so I ordered a pair of new converters this morning from napa. Should have them this afternoon. Going to remove the "y" ahead of the converter and go true duals. Two cats and no mufflers. Too bad I won't get to hear it until I get my carb parts.

[rusty76]

That's a good looking adapter. Great job. I likes it.

[ChevDog1]

Got started on the exhaust while I was waiting for parts. Court out the existing system just ahead of the "y"...

[ChevDog1]

Drug the rest of the system out from under the truck.