I picked up a Holley carb, 390 cfm, the type used on '62-'63 HD 292 trucks. C3TW 9510 F, List 2151 1. It came with the governor on one side and a manual throttle on the other. My mechanic took it apart yesterday and it is in good rebuildable condition. In removing the gov and hand throttle, I will loose a functioning choke, and will need to weld a bracket onto the throttle shaft for my throttle cable.

This carb had two, two stage power valves. Bill said to forget them and go with regular power valves. Dont know if new Holleys work like this but the idle circuit adjustment is on the secondary bowl. Still no provision for a PCV. Also will need to put in a protection for power valve blowout due to backfire.
A blocking mechanism on the throttle will also have to be added, due to the throttle shaft currently going beyond the center point of WOT.

It should be interesting. During research prior to buying the carb one guy said the governor couldnt be removed on these carburetors, but that appears to be wrong.

Bill rebuilt many carbs while in CA. These came in for service from trash haulers. He had a story about one driver that wanted more getup and go. Bill did some "alterations" to the governor, but it all had to be redone, because when the driver stomped on it the truck lurched forward rapidly, but just as fast fell on its nose, making it impossible to drive. It was a good laugh .

The jets were/are 52 primary and 58 secondary. I would like to change them to 49 primary and 55 secondary.

When all is done I expect to have no more than $100 in this, so it may be worth it to pick one up if it is reasonable. I'm hopeful that a simple bracket can be made for the use of manual choke. If not, oh well, as the current carb doesnt have a choke either.

 

I went over to Bill's today to give him some gaskets for the carb, and it was already done. He wasnt too pleased with the amount of work it required, 6-7 hours, and he works fast. The picture below shows the throttle side and all of the linkage that had to be made. Throttle lever, accelerator pump link and cam, idle stop/adjustment, and other stuff. So this isnt probably something that could be recommended. He is confident it will work very well. But I couldnt have done it, and any other professional would charge a lot more than $20 for parts and $55 labor.

Choke is fixed open, secondary power valve was replaced with a plug. The brass plug in the center of the carb shown in the pic is a vacuum port, so may use it for the distributor.

 

WOW! That guy works cheep!!

That carb looks like a 4150/4160 like the one I pulled off my OMC 460!




By the way,


Here's the one I ordered for my 292. I settled on Model #0-8007, 390 CFM model.

 

Rick, to me it looks more like the one you ordered. I noticed on the one you took off the 460 the idle circuit adjustment screw was on the primary side. This one for what it is worth is on the secondary side. I wish someone familiar with the 62-63 HD 292s could tell me exactly where the distributor line was connected.

You should like the 390 I think. They are tried and proven on these engines. The 480 cfm Autolite I have would most likely be a bad match for the old tranny. But maybe the Holley will be more foregiving, as long as there arent any BURNOUTS. Sure wanted to change out those jets before it went together, but that isnt much to do with the carb on the bench. Do you happen to know what size jets the new 390 has installed?

 

I got 48 primary and 52 secondary in the one I rebuilt. I think I need to go to a 50 primary and a 55 secondary to max out the perfromance.

Is that a holley 3bbl? Is it for sale?

 

Thanks for the jet info. It tends to confirm changing to 49/55. Dont care about max performance but looking for mpg. Yeah I know, "then keep your 2100".

 

Mike, yes, the idle mixture screws are always on the primary side aren't they?

I am surprised that yours are on the secondary. How would that work?

Are you sure that they should go on the sec?

It almost appears that someone might have put it back together "backwards" before you got it...... I seem to remember that the block with the jets and screws would have gone on either side.

How would you adjust the idle on the secondary side? (unless there's an idle screw on the secondary throttle shaft) I guess there's no reason why it wouldn't work unless you couldn't completely close the primary throttle butterfly.....

My (marine) 4160 also only had a power valve and removable jets on the primary side. Everything on the secondary side was fixed.


I don't know. I was just going to try it and decide whether I might need to change them later.....

 

Rick, I dont know, and can only go by the experience of the mech. He found it curious, and explained in a way totally not understood, why it had to be that way. Also notice the brass tube running behind the fuel tube. It was used to equalize fuel levels in primary and secondary. It is all beyond me, but sure going to see how it works. The only carb I understand is the 2100/4100. So we will see. Need to get a phenolic spacer and 4 hole aluminum spacer. Will drill and tap the 4 hole on each side for PCV. This may be on who knows when, but will be on.

 

I seem to get better milage with the holley 390 than with the 2100 I pulled off.
That brass tube is kinda odd. I know that some holley DP carbs have secondary idle circuits in them but they also have it on the primarys.

 

Mike the model carb that you are using has the idle air adjustments on the secondary side. Typically the distributor vacuum advance line is connected to the front metering block on the passenger side of the carb. I've done this changeover several times with mixed results. If you need more info let me know.

Have A Great Day ------ Hotwrench

 

Mike,
I have the same carb recently removed from a early 60's big truck. The distributor is crazy looking! It had the line to the carb for the Governor and the Vacuum advance went to where you have brass plug. Mine has a 90 degree fitting with a nipple on it.

I removed it from the engine and thats the way it was.

 

Hotwrench, I looked over the carb closely, with glasses and flashlight , and there isnt anything on the passenger side for the dist. vacuum tube. The only thing there are two blind threaded holes (probably part of the hand throttle mounting), and an unused port for idle circuit adjustment on the primary metering block. Dont believe it goes anywhere. Also, you referred to mixed results. Give it to me please, good and bad.

Kevin, do you think the center port where the plug is now is a ported vacuum source? When it is installed I should be able to tell if yes or no. Out of curiosity post a pic of the distributor. It figures that it is unusual, because in its original form the carb looked ALIEN.

 

Mike typically govenor style carbs are of two types variable speed and fixed. The variable ones are used in truck applications and the others are fitted to industrial units such as pumps and wood chippers. The fixed ones do not do well on the street as they idle well and run at govenored speed
OK . The variable speed carbs are set up for heavy loads and not fuel economy. Leaning them down sometimes presents problems with transitional throttle [ IE dead spots -- lean surge ] . Its possible that this carb has no port for vacuum advance, as the application it was used on had a full mechanical advance no vacuum. The port on the driver side with a plug in it went to the distributor govenor vacuum control. This port is usually a vent from the distributor and leads to the airhorn area.

Have A Good Day ------ Hotwrench

 

This may help.

 

Well, maybe this: