Gramma's Car: the new project!

[John Brown]

Looks to be a 750 by this picture.

[earntaz]

Yep -- doesn't appear to be a "bump" in the venturi ... TAZ

[VintageMusclecar]

I must make a confession;

I wasn't sure I was going to be able to save this carb. [img]<<GRAEMLIN_URL>>/blush.gif[/img]

When I started to build the sub-assemblies, I realized this carb was warped a <span style="font-weight: bold"><span style="font-style: italic"><span style="text-decoration: underline">lot</span></span></span> worse than I'd originally thought. While the bow wasn't <span style="font-style: italic">super</span>-bad at the front, the carb was warped like hell in the center of the casting. I noticed this somewhat during dis-assembly but didn't realize how bad it was until it started to go back together. I actually had a little trouble getting a few of the screws started because the body still had some warp in it that I simply could not get out.

That said....

drum-roll.......

It runs.

Not only does it run, it actually runs pretty damned good.

It idles beautifully at ~750 rpm, transitions nicely on the way up, and the throttle response is razor-sharp.

I was all but certain this carb was going to kick my ass and make me look like a chump.

Whod'athunkit?!?

I didn't have a correct pull-off in stock so I have to order that in, but other than that it's done.

I'll post a couple of pics and a live test video later.

*whew*.

[njsteve]

Awesome! For a junk carb that was thrown in with the engine block I bought, it's sure nice to know that there are artisans out there who can turn a sows ear into a silk purse. [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]

[njsteve]

I'm out in the garage today. Just got the 350 engine pulled out with the help of the wife and the boy (both of whom promptly ran off to go shopping and back onto the Xbox, in that order).

[VintageMusclecar]

A couple of pics on the test engine. Again note I didn't have a correct choke pull-off in stock so I just capped off the vacuum port so I could run it.







There are two small tabs on the top casting that are meant to act as a closing stop for the secondary air doors. Unfortunately on this carb, one was broken off completely and the other was badly worn. Since the carb <span style="text-decoration: underline">must</span> have some means of preventing the secondary air doors from trying to close <span style="font-style: italic">too</span> far, I employed a common trick of using a small flat washer under one of the rear-most screws to act as a stop.

Ain't pretty but it works, and it saves an otherwise junk (and somewhat hard to find) casting from the scrap heap.



Click the pic below for the video. Please note the air/fuel readings aren't entirely accurate on the meter. The rings in my test engine are beyond shot, and as such it huffs a considerable amount of oil which skews the readings. (I really need to get that poor thing rebuilt, but I just can't find the time!)

FWIW, the ~12.5 a/f ratio on my meter directly correlated to a ~14-1 a/f ratio on Kammers dyno, so you can extrapolate from there.



Steve, I'll give you a shout next week as soon as I've got the pull-off in.

Thanks again for letting me be a part of the build.

[njsteve]

That is way too cool. [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]

You know, Eric, I consider it your fault that I am going to have to detail the engine compartment to match that snazzy looking carb.

And then I'll have to repaint the 25 year old paint job on the car...

And then update the suspension...


another example of &quot;Give a mouse a cookie...&quot;

[njsteve]

BTW, what vacuum ports are full vacuum and what are ported? I usually run the distributor vac advance off of the full vacuum coming from the big cast aluminum &quot;T&quot; that comes of the back of these Pontiac carbs. If this one actually has a port for the vac advance I'd be happy to use it. (It also needs to use of of the vac ports for the auto trans vac modulator).

[VintageMusclecar]

This carb only has two vacuum ports aside from the one for the choke pull-off:

The one on the base is manifold, the one on the top pass. side above the pull-off port is ported.

The back of the base does have the 1/8&quot; pipe thread boss if you have a vacuum tree for it.

[VintageMusclecar]

BTW, I wouldn't worry too much about having to detail the engine bay because of the carb...that's one of the cruel ironies of my profession--all my hard work is usually hidden beneath a big ugly-assed air cleaner lol.