The Stovebolt Site Forums The Shop Area Engine Shop stalling on inclines

Hi, I am new to the Stovebolt Forum. I hope I am posting my question in the propers place. I did not go back through the thousands of post to see if others have had a similar problem. I appears there is away to have my post forwarded to another thread, if there are others that have similar issues.
Here is my problem: I have a 53 3100 p/u. The engine has been replaced with a 59-62 235. The carburetor has been replace to a pair of Holley/ Webber 2 barrel/ 2 stage model 5200 carbs. This set was sold to me back in the early 2000 from Tom Langdon (the [email protected]) as a matched set.
When the truck was completed it ran fine with no power loss issues. Now as soon as there is any pull on the engine, you have to gear down to get it up any kind of an incline. Eventually it will just stall out. I have it in a shop. The mechanic has tried a number of things to try to resolve the problem. It now has an electric fuel pump. Lines have been check for plug issues. A regulator has been added to insure we are getting proper fuel pressure and the carbs have been completely rebuilt. The truck has a Chevy T-5 transmission. Rear-end gearing has been changed to give approx. 2200 rpms at 70 mph.
Any ideas on why I am loosing power?

You're in the proper place. Thanks for asking. I'm sure help will be along soon.

That sounds to me like a float level problem. One of the experts on those carbs can probably give you more details.

What rear end are you running? 2200 RPM at 70 MPH is why you need to downshift on an incline.
With all of that carburetion, you need to spool up the RPM to realize any gain with that setup on a 235.
Not saying that you may not have another issue going on, but a setup which gives you 2200 RPM at 70 MPH is not a great starting point.

You must have a very high geared rear end. My Chevy 3600 with a final of 3.55 with the overdrive, has a speed of about 55mph at 2200rpm. No lack of power with the twin two barrel Weber carbs.

My 250 runs 2550 rpm @ 70 mph with a 28" tire with an automatic T350 trans, so no down shifting. Try the same hill in 4 gear, if it still " looses power " then look for a lean condition, maybe your fuel has changed in your area or the carbs have blockage you haven't got cleaned out yet. Check the distributor and make sure it's timed right and the advance isn't stuck. I doubt the muffler is plugged up, but check it along with dirty air filters, especially if you have those really small diameter dual filters.

If you haven't done so in a while, run up to full rpm through the gears to get it " cleaned out " as we used to say. They need run every so often, my dual Carters need it often if I don't drive it very much. After a good run up, mine idles much smoother and just runs better till it sets for a month or so.

Take the top off one of the carbs. Those 5200s have the main fuel jets on one side of the bowl at the bottom. Its really common to install these carbs backwards so that the main jet is in the front so that when you are inclined, or really getting a jump off the line, you end up exposing the main jets and getting a stumble or stall. The fuel bowl in those carbs are not very deep so its imperative that the jets be toward the firewall. Check that first just to eliminate that as a possible cause.