304 has no get up and go

[zig]

I just bought a 79 CJ7 with a AMC 304 in it a few weeks ago. It seems to run decent until i put the pedel down then its like it has no power. It had a holley on it when i bought it and it just backfired when you stepped on it. So i put an edelbrock carb on it and new fuel filter and fuel pump, that got rid of the backfire but it has no power when you want to go. If you ease into it then its ok. I don't know if its the carb or something else. Any help would be great. thanks

 

[Old Dog]

What size and what kind of carb? Both holley and edelbrock make different kinds and sizes of carbs.
Also if you fill out your profile it would help us now and in the future.

 

[zig]

The Edelbrock is a performer 600 and i'm not for sure what the holley is that came on it. I will get my profile filled out thanks for the info.

 

[Kane]

There is a possibility you have a worn cam lobe. That symptom is what happens. Everythign sounds and feels nice until you step on it, then the motor needs more air and fuel but that piston cannot get any so it falls on its face. Most likely it is your farthest back cam lobe and the #6 or 8 cylinder is affected. This happens from oil starvation.

 

[GoldenEagle36]

could have too much gas going into the engine check the carb
im not sure tho

 

[Kane]

The only thing about that is he replaced the carb with a new one. Another thing to check is your ignition timing and your advance on the distributor. At idle you should be around 8 BTDC and at 3000 RPM you should be around 35-40 degrees BTDC. Each motor is different but that is a rough number. If your mechanical advance weights in the distributer are stuck then you are not advancing your timing while revving and it will kill your power.

 

[Old Dog]

could have too much gas going into the engine check the carb
im not sure tho

The only thing about that is he replaced the carb with a new one. Another thing to check is your ignition timing and your advance on the distributor. At idle you should be around 8 BTDC and at 3000 RPM you should be around 35-40 degrees BTDC. Each motor is different but that is a rough number. If your mechanical advance weights in the distributer are stuck then you are not advancing your timing while revving and it will kill your power.

Both great ideas. A 600 cfm carb is to big for a AMC 304 , and as kane said your advance might not be working right. I've never had a cam go flat on me so that could be something to check also. You can check the cam with a dial indicator and the timing with a timing light. I would also sugest a smaller carb, more like a 450 cfm or so.

 

[Kane]

A quick way to check to see if your carb is too big, put a ziptie on the linkage for the secondary linkage in a manner to disable the second barrels. This will effectively make it a 300 cfm two barrel. If you are killing your motor with a large carb this will give you a clue. With only two barrels working it should run better since it will be getting less air and pool.

 

[asfaultdemon]

i personally run a 750 cfm holley dbbl pumper on my AMC 304 and have no problems . So if you ask me the power loss is that pile of poop edlbrock. And the popping and back fire was either a blown power valve in the holey or a timming problem. i had alot of the same problem (note the points if it has them) I fixed it by putting a dummy chevy HEI covertion distributor in and running a MSD 6AL. Now my AMC 304 out powers my bothers fresh 360 and mine has alot of miles on it. Iv seen 4 cars burn to the ground due to using a edelbrock carb so in my opinon they are junk iv got 5or 6 of them i made ash trays out of and i dont smoke LOL. So my advise would be check the power valve and see if that was the original problem if it was then check the timming and point aswell as the mech adv.. Iv seen a vacume leak do the same thing in some of my race cars if the leak is on the metered side of the carb it wouldnt have vac till you step on the gas ten it would cause a huge leak. Just a few things to lok at i could be way off base