Step 1: The Teardown
Holley offers two different kits; one is a basic rebuild kit that has all the gaskets, power valves, accelerator pumps, and other service parts to do a rebuild. The second is a trick kit that gives you everything the basic kit comes with, along with a bunch of tuning parts to adjust for different motor and cam selections. Ours will be going on a stock 350, so the trick kit is not necessary. Depending on what you need your carb to do will dictate what kit to buy, and if you are not sure, call Holley's tech line and they can lead you in the right direction.
Additionally, before ripping into the rebuild, it's a good idea to have a few little containers to hold small parts. And, if you are real serious, there are many books written to help you along the way.
1. To start, drain all the...
1. To start, drain all the fuel out of the bowls and give the carb a good wash. We used this new table-top wash tank from Oil Eater that uses the company's non-solvent cleaner. It cleaned the carb perfectly and didn't affect the delicate Dichromate Finish.
2. The fuel bowls will be...
2. The fuel bowls will be the first thing to come off; they are held on with 5/16 bolts. The bowls can stick, but fight the urge to pry them off with a screwdriver. A couple medium to light taps with the handle of a screwdriver should be enough to pop them free. As you can see, this carb has the blue gaskets in place already. This is what told us that it had been rebuilt.
3. Look what we found hiding...
3. Look what we found hiding beneath the blue gasket, remnants of the original gasket material. This is not acceptable. Holley makes good gaskets, but to think they will give you a perfect seal over this crud is just ludicrous.
4. With the bowls off, we...
4. With the bowls off, we moved on to the baseplate, which is held on with Phillips-head screws. Once you have them out, separate the main body from the baseplate and inspect the base around the mounting ears. It's pretty common for these to crack from being over-tightened, but luckily, ours was in perfect shape.
5. The basic rebuild kit comes...
5. The basic rebuild kit comes with a few different base gaskets, so before you destroy the old one removing it, find the right one and set the others out of the way. This will cut down on confusion and prevent you from inadvertently installing the wrong one.
6. Moving back to the top...
6. Moving back to the top of the carb main body, the accelerator pump discharge nozzles are removed with a Phillips screwdriver. The nozzles should be the same size for the primary and secondary circuits; ours were the factory installed 28s.
7. Hiding underneath each...
7. Hiding underneath each nozzle is a little needle, which can be shaken out by flipping the body over, but be careful. Lose one of these and you are dead in the water, until you can get a new one or find the one you lost. The needle prevents fuel from being sucked out of the nozzle when air passes by the venturi.
8. Because our carb is missing...
8. Because our carb is missing the choke assembly, we can move on to tearing down the bowls and metering blocks. There is only one power valve on the non-dominator-style carbs like this one. It is in the primary metering block and requires a 1-inch wrench to get it out. If you have a choke assembly, remove the little clip from the linkage rod and remove the three screws holding the assembly on.
Step 2: Inspect And Clean...
Step 2: Inspect And Clean
1. Pull the jets out of the metering blocks and give them a good soaking with the carb cleaner. Keep track of what jets were in what metering block, but if you forget, the smaller-numbered jets go in the primary metering block. Also, compare the old power valve with the new one, making sure they have the same numbers stamped on them. Ours had a six and a five stamped on it, letting us know these will open at 6-1/2 inches of vacuum. The rule of thumb is to have a power valves that are marked with half the amount of the truck's vacuum at idle and 6-1/2 is perfect for most stock small-blocks.
2. Most damage that is done...
2. Most damage that is done happens while you are removing the old gaskets. We used Gasket remover from Permatex that eats the material and makes it very soft and easy to remove.
3. As you can see, after a...
3. As you can see, after a few minutes the old gasket has softened up and easily comes off with our plastic scraper. Try not to us a metal scraper, since it can scratch the metering blocks and possibly hinder sealing.
4. After we got all the gasket...
4. After we got all the gasket material cleaned off, we noticed this little imperfection on the main body that was caused by someone aggressively prying off the metering block. This is why we recommend lightly tapping on the bowls to break the seal.
5. To cure this little imperfection,...
5. To cure this little imperfection, we took a fine file and ran it across the main body until the nick was gone.
6. After all the filing and...
6. After all the filing and gasket-scraping was complete, we hosed all the parts down with Gumout Carb and Choke Cleaner. This will remove any varnish or crud inside the passages, which will hurt performance.