57 Chevy BelAir Gasser Build

^^^^^^^^^^^^^^^I would trade mine for "something interesting"! ^^^^^^^^^^^

 

Thanks again for the thread. I have a complete '57 truck axle I was, can use for my build BUT I think they look a little wide. Does anybody narrow an axle like this "safely"?

 

The '55-'59 year range Chevy truck axles are wider than the earlier generation Chevy truck axles. You could get an earlier one of you want a touch narrower and not need to modify. Bill does the custom work, straightening etc. though I believe at WAC as well. My axle is from a '56 Chevy, I do like the width with my wheel and tire setup, but I'm going to swap to a straight axle from WAC Customs because I don't like how much gap I have to make up between the spring eyes and the frame at ride height, and I don't want hi-arc springs. I just need to swap the inner bearing and seal for the difference in bearings since I'm switching to car spindles. I have a Speedway disc brake kit installed that I want to reuse.

Anyway...Here a little info on some factory source gasser axle options:

1928-40 CHEVY CAR OR PICKUP AXLES

50-1/2" kingpin center to center

26-3/4" spring pad center to center

1-3/4" wide spring

0.734” dia. kingpins

2-1/8” tall kingpin boss


1933-39 CHEVY CAR AXLES

50-1/2" kingpin center to center

28" spring pad center to center

4" factory drop

0.734” dia. kingpins

1-3/4" wide spring

1933-36 car axle 1-3/4” tall kingpin boss

1937-39 car axle 2-1/8” tall kingpin boss

1939 axle has hole for shock mount by KP boss


1941-55 CHEVY / GMC 1/2 TON SERIES 1 PICKUP

50-1/2” kingpin center to center

26-3/4" spring pad center to center

1-3/4” wide spring

4-1/4” factory Drop

2-1/8” kingpin Boss

0.866” dia. kingpins


1947-54 CHEVY/GMC 3/4 - 1 TON SERIES 1 PICKUP

50-1/2” king pin center to center

26-3/4” spring pad center to center

2-1/8” tall king pin boss

0.921” dia. kingpins

2-1/8” tall king pin boss

1-3/4” wide spring Chevy

2" wide spring GMC


1955-59 CHEVY / GMC PICKUP AXLE 1/2 TON SERIES 2

54" kingpin center to center

31-7/8” spring pad center to center

4-1/2” factory drop

0.866” dia. kingpin

2-1/8” or 2-1/2” kingpin boss

Some years have a bearing, some have a thrust washer.


1955-59 CHEVY / GMC 3/4 TON 1 TON SERIES 2

55-1/2” kingpin center to center

31-7/8” spring pad center to center

2-3/8” tall kingpin boss

0.921” dia. kingpins

2" wide spring


1964-69 CHEVY VAN

54" kingpin center to center

35-3/4” spring pad center to center

2-1/2” wide spring

0.8125” dia. kingpins

2-1/4” tall king pin boss

4-1/4” factory drop

Number stamped on this axle 3892504GM12

 

Wealth of info, thanks! I have been saving parts for this build for 50 years, picking things off the shop floor, benches & hiding places for a period correct build. Hard to pic between "period" & "safety". Front axle is either going to be WAC or a chevy truck axles. If you ever think I am stepping on your thread just say so, just thought it would be redundant to start another.

 

If im not mistaken, these breathers were made by Richies Nostalgia(later Arias Components) from the actual Mickey Thompson patterns.

 

Questions and discussion are great and welcome but you should definitely do a build thread for your car when you get rolling on the project. Hard (and no need) to meddle two car build threads together.

 

Don't think the HAMB needs another try5 gasser build, yours with info is enough for most!

 

HEY hay now.. HE ain't no 'Y'-word
We Kool?

 

I had them before Richie started advertising his scoops here, not sure who made them originally.


And on the earlier year axle thing, prior to 55 the leaf springs weren't parallel, the back was wider than the front.

 

^^^^^^Bingo!^^^^^^
"And on the earlier year axle thing, prior to 55 the leaf springs weren't parallel, the back was wider than the front."

 

I needed a spacer on the blower drive, Rick hooked me up with a nice machine piece. Did the trick and lined up the pulleys perfectly, just grabbed a set of longer bolts and all good. Rick uses 50/55 pulleys, I've got 53/59 setup on mine so not a lot of slack in the belt for the idler. Any thoughts on that?

 

I narrowed a Chevy axle years ago, to used under the front of an A roadster. Welded the spring perches, and 4 link brackets to the axle as well. Ran it in my street car for 24000 miles, then sold the car. I didn't do it, but you could add a piece of rod in the relief on the back side of the axle, to act as a gusset.

 

Seems I always see idler pulley on those GMC blowers to take up the slack. Will you have trouble tossing the belt off?

 

Aluminum expands alot when it's heated, aluminum manifold, aluminum blower, aluminum brackets, that belt will tighten up more than you think. They like 3/4" movement left & right. Get a longer belt!

 

I'll definitely be rubbing an idler on a swing arm bracket but that was my question is if the slack is minimal or should be more for the idler to take up. I wasn't going to run as is lol

 

This is exactly TRUE! I have my blower belt at nearly one inch of slack, cold. When the engine is at at operating temperature it is very snug but not banjo string tight. The belt adjustment is critical, I have seen them run to tight and break the bolts on the crank pulley and break the snout off the crank. That makes one hell of a mess when it occurs. 3/4 to 1 inch slack cold, Gary Dyer told me that when he built my blower.

 

That's the kind of info I was looking for thank you. I have my idler bracket being machined at a buddy's shop right now but I have the idler pulley ready to go. I might need a longer belt or swap to the 50/55 pulley setup. That's what this belt was designed for.

 

That set blower setup might be what it's set up for but wouldn't your motor dictated the boost you want & what your motor can handle?

 

Glad I could help brother. I like your car and the build.

 

Awesome thank you.

 

I'm not sure I'm following what you're saying here exactly...

 

Your not the first or last one! Start changing top & bottom gear numbers and you change the boost. At the risk of you may already knowing this, belts have diff. pitches, gear teeth have to match.

 

The drive ratio determines how fast the blower spins. The C.I.D of the engine determines how much boost will be produced. More cu. in. = Less boost for a given drive ratio and vice versa.

 

^^^^^^^^^^^And that's how you explain things in English!^^^^^^^^^^^^^

 

Not mentioned but lay a straight edge on the long side of belt up against the blower and crank pulley, take a ruler and push the belt towards the center of the engine to measure.

 

Oh ok tracking, the way it was worded just tripped me up sorry about that. Yea I looked this setup up in my charts and found it to be a -10.2% underdrive setup, whereas 50/55 would be -9.4%, which seems pretty minimally different. I'm running the proper 8mm pulleys and matched belt, no 1/2" pitch stuff. I'm only curious if the length of belt doesn't have enough slack to set the idler and cold tension. Seems like minimal slack belt to work with but we'll see once the idler pulley and swing arm are actually installed and go from there.

 

So how do you know in advance how much boost will be made, or is it just to make a best guess and install a boost gauge and see where you're at once running and go from there?

 

One you do this, what do you do with that info? And what's the ideal target measurement?

 

You really don't know how much boost you're making until you have a gauge to read. Those charts are compiled from years of testing common combinations, and are generic at best. Which, is not to say, that they aren't close, because they will get you in the ballpark. It's just best to get a good positive reading from a gauge.

 

As I posted , 3/4 to 1 inch slack, cold. If the belt is to tight checking it with the method swade41 has showed you, then you need a longer belt. I have several length belts for different pulley combinations. Yes ,use a quality boost gauge