I'm going to be going over my Holley Street Avenger 670, and I need to know what kit to buy. The renew kit for the 4150 carbs is the same price as a trick kit ($95.99.) What does the trick kit have that the renew kit does not?

EDIT: Some of you know that I'm in the middle of doing quite a bit of work to my engine. I will be in the 400 hp range. Should I just get a fast kit and rebuild it to factory specs and see how it runs? I wouldn't be touching it until the engine is put back together but I'm quite sure I have crud in the carb (the car sat for years before bought it, I was going through a fuel filter every couple of days with the new engine.) It has a severe hesitation that I could never get to go away. It wasn't there when I first bought the carb, but it developed and became worse overtime.

 

http://www.summitracing.com/parts/HLY-37-933/
If the kits are the same price, I would go with the trick since it gives you some extra stuff to play with. Right off the bat I see a couple of power valves, a bunch of accelerator cams, a few accelerator diaphragms, and a gaggle of gaskets.

 

That's what I'm thinking... I'm in the middle of pulling the engine right now. When I dumped the fuel out of the carb, what came out of the rear bowl was brown. Opened it up and there's plenty of crud built up.

Do I need all that extra crap though? Seems like I'll be paying for a lot of stuff I won't use since it's a universal kit. If I rebuild the carb to factory specs, then get a jet kit and an assortment of discharge nozzles and change out the power valves, would that be a good option? What else would be a good idea to get?

I don't have much experience in performance tuning a carburetor, only stock rebuilds.

 

Murphy's law...if you have it, you won't need it. And if you don't have extra parts and start fiddling with the carb, you might need it. If your carb was working fine before, but the only issue is the crud, then go with the basic rebuild kit. That's a lot of "ifs" aint it?

 

I don't know what I'll be doing now. I disassembled the bowls and found that the zinc coating is separating from the main body. I don't know if I should try to scrape it off or what. I'll be sending these pictures to National Carburetor (it has a lifetime warranty, I'm not sure if it's covered.)

 

Oh man that's gross, do you have sand in your gas tank or what? Actually it looks like old gas and water mixed together. Was your car ever sitting for a loooong time? And how old is that carb?
If the company doesn't cover the peeling, then I would carefully try and get as much of it off with a razor blade. Then find yourself a piece of tempered glass, tape a piece of sandpaper down to it, and mill it down smooth. I used to shave Briggs & Stratton heads that way back when I was kart racing. Gotta take it slow and keep it flat.

 

Best I can gather is that the car sat for a LONG time before I bought it. The PO did some work on it to get it back on the road, but the 305 never ran quite right. When I yanked it I found that the fuel filter was completely packed full of sediment.

I decided rather than drop the tank I would try and run all the sediment out after I put the new engine in... I literally went though at least two dozen fuel filters. I was at the point where I was buying them 4 at a time.

Finally I knew the tank had to be dropped (fuel gauge didn't work anyways, I'm sure you remember helping me with that though.) Once it was out it was was the most disgusting tank I had ever seen. I had it cleaned out and I installed a new sending unit and pickup. I still get a bit of crud in the fuel filter, but the last one I had on for over a month and it still looked halfway decent.

Btw, the carb is less than 2 years old with under 5,000 miles on it.

 

I recognize that crap you have. I once bought an old Vette that had been sitting many years. The pre-unleaded style tanks have a filler opening that's a good 2.5" in diameter, and you can look straight down inside the tank. The gas was pure orange and had some floating slime covering the top of the gas that looked a lot like what you have in the carb. You were fighting a losing battle before you dropped the tank. That must have been some nasty corrosive stuff to eat at the carb that fast.

 

Well I spoke with Bryan at National Carburetor. He said that since I opened the carb I voided the warranty, BUT, he said to put it back together and send it in and they would rebuild it with a new main body. I'm only out shipping. I think I'll put it on the new engine and see how it runs, then get the trick kit once it's back on the road.

 

"These Holley Trick Kits are the inexpensive solution to fuel slosh in your carburetor. The kits contain all of the parts you need to perform a complete rebuild on your Holley carb, including a vent baffle, high-flow needle and seat assemblies, high-capacity power valves, pump cam and secondary opening spring assortments, gaskets, and O-rings. Plus, they have extra parts related to carburetor calibration that are required in order to accomplish a real performance tune. These include accelerator pump discharge nozzles and extra gaskets. A carburetor exploded view and detailed tuning guide are also included, with packaging that serves as a handy parts tray. These Holley Trick Kits have it all."

I'd consider pulling a swab through the gas lines. I usually use a vacuum to suck a strong twine through the gas line, then tie a small piece of cloth that fits inside the fuel line to the end and pull the swab through to clean all the crud out of the line. You could change filters for a long time, and never get it all out without either cleaning or replacing that fuel line.