I bought my first jeep last year. It's a 1978 CJ5, with a AMC 304. The guy before me had put a 4 barrel eddlebroke intake on it, and had a 2 barrel holly carb i wasn't too fond of.
After doing some research, i found that most people recommended the motorcraft 2100, or 2150. So i found a new never been used 2150.
Then i picked up a 4 to 2 barrel adapter plate that doesnt fit so well on either side, and had to rig up another 2 adapter plates on each side of my adapter plate. Needless to say, i always seem to have a vacuum leak, and the thing wont idle.
I feel like maybe i should do one of a couple things, and hoping i can get some expert advice.
1) Find a real adapter plate that bridges these two truly, but i can't locate one, so maybe i just need to find somebody to can make me a custom plate, but not sure who to turn to there either.
2) Find a stock 2 barrel intake from the junkyard, and slap it on, making my 2150 fit better. But my questions then are, would i be losing performance? Would it be more gas efficient?
3) Say screw it all and get a 4 barrel barrel carb like maybe the 600 Truck avenger. It already has a 4 barrel intake so my guess is they are going to fit better and maybe just have less heartache, and maybe better performance?
What's you guys opinion? What would you do?
Last edited by somerandomguy; 09-17-2015 at 03:20 PM..
Unless you know how to tune a carb, I wouldn't get a Holley Truck Avenger. While a Holley has a lot of adjustability, few folks understand how to adjust. I would recommend an Edelbrock 500cfm performer with the following modifications:
1. remove the top off the carb (very easy to do...youtube if you don't know) Use 3/8" fuel line and cut three short lengths (about 1/2 inch) and block off the bowl transfer port in the back of the body, one in the middle and one on each end (yes, I know, this is overkill, but I like to make sure gas doesn't transfer). You simply cut the line so it will fill the port top to bottom when you fold it, hole facing up, and stuff it into the slot running side-to-side. This will keep the fuel from running to the low side bowl on a side hill.
2. install the spring loaded needle kit. Here again, easy to do and cost is $14.
3. Set your float at 3/8" using a drill bit under the nose of the float. Don't push down on the float when setting, just let the spring hold up the float and bend the tab to set.
4. Set your air/fuel screws to 1 1/4 turns out as a start. You won't need much adjusting after that.
5. Set your timing at 14 degrees advanced without the vacuum advance hooked up.
6. Purchase the Mr. Gasket fuel pressure regulator number 9710 at Advanced Auto or similar. Also purchase a fuel pressure gauge from the same store and install these in the fuel line after the pump and before the carb, the gauge after the regulator. The number one problem with carbs in 4x4 activities is that the gas will continue to fill the bowl as the float bounces...and yes, it still bounces with the spring loaded needle. When you hit the trail, set your fuel pressure to 1-2 pounds (I run mine at 2 pounds rock crawling and running sand). If you forget to reset for the street, you will know as the motor will run out of fuel when you accelerate and cough and sputter.
My son has a the Truck Avenger on a 350 chevy in a CJ7 and has never been able to get it tuned for rock crawling, but lives three states away, so I can't tune it for him. He is so disgusted with the Holley, he had me purchase the TBI conversion parts and will be here in a few weekends so I can convert. Tried to talk him into the Edelbrock, but he now hates carbs since the Holley has ruined a number of his wheeling runs.
TBI is by far the best solution, but it's about $1000, so expensive. The 500cfm Edelbrock can be made to work very well with a few mods. I've been using this carb for years on various jeeps, and after tuning, they run great, but most don't know how to make them work for anything but the street. Lower fuel pressure is one of the key elements.
I am running a 1406 on my 304, so 600 cfm, only because the PO purchased just before selling his jeep to me. He could never get his Holley to work right rock crawling, so swapped for an Edelbrock. Unfortunately, Napa Auto sold him a 600 cfm instead of the correct 500 cfm, but I was still able to make it work, as the 500 and 600 share the same body but use a different primary booster. He also had the ignition retarded, which was another problem. After tuning, I can crawl or full power without a problem.
The last thing you will want with any carb is a hand throttle. Cheap and easy to install, and eliminates your foot bouncing on the gas pedal.
Truck avenger. You can not go wrong. I completely disagree on tuning. I find holleys very simple to tune and easy to do precise adjustments. I have the 770 on my 401. Great carb. You will not be disappointed.
Had a Holley on my 304. It was too big and difficult to tune. Made tons of top end power but drivability made me convert to the 1406 manual choke eddy. The 1406 Looks nice and is easy to tune but the Holley made gobs more power.