Engine New CJ5 304 Owner - Advice Needed

[TrackRat]

Hey there - Just picked up a '76 CJ5 from a friend of mine. In the process of getting the motor tuned up and running well. Swapping out the stock 2100 Carb with a Holley 2300. Have a 350 and a 500 headed my way. Curious for some thoughts / advice on which CFM you'd run. Motor has been bored to 309 (from 304) and apparently has a cam (don't know the specifics) and long tube headers. Most focused on a smooth running reliable motor.

Thanks in advance!

 

[Manic Mechanic]

Is go with sniper EFI

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[CJ]

Hey there - Just picked up a '76 CJ5 from a friend of mine. In the process of getting the motor tuned up and running well. Swapping out the stock 2100 Carb with a Holley 2300. Have a 350 and a 500 headed my way. Curious for some thoughts / advice on which CFM you'd run. Motor has been bored to 309 (from 304) and apparently has a cam (don't know the specifics) and long tube headers. Most focused on a smooth running reliable motor.

Thanks in advance!

A 600 cfm carb covers most engines under 400 ci. A little larger won't hurt.
Here is a handy cfm calculator.

https://www.summitracing.com/newsandevents/calcsandtools/cfm-calculator

 

[TSB8C]

Is go with sniper EFI

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You want smooth running, easy cold starts, good streetability, handle extreme angles or higher altitudes? EFI.

 

[TrackRat]

You want smooth running, easy cold starts, good streetability, handle extreme angles or higher altitudes? EFI.

Agree - at this point I’m trying to figure out the full extent of spend on this rig. For now just want to get it running well with a carb and will go back and re-evaluate EFI once I have sorted the rest

 

[NP435]

Hey there - Just picked up a '76 CJ5 from a friend of mine. In the process of getting the motor tuned up and running well. Swapping out the stock 2100 Carb with a Holley 2300. Have a 350 and a 500 headed my way. Curious for some thoughts / advice on which CFM you'd run. Motor has been bored to 309 (from 304) and apparently has a cam (don't know the specifics) and long tube headers. Most focused on a smooth running reliable motor.

Thanks in advance!

Edelbrock has carbs intended for off road, but you already had a good carb in the 2100 Motorcraft. Any quadra jet in the 650cfm range will work too. I have no idea if the quadra jet works at steep angles. My 2150 works fine.

 

[TSB8C]

Agree - at this point I’m trying to figure out the full extent of spend on this rig. For now just want to get it running well with a carb and will go back and re-evaluate EFI once I have sorted the rest

Carb is usually cheaper and can work just fine for most situations. As you probably can tell, I'm a fan of EFI (obvious bias) and won't go back to a carb. But overall cost and complexity is certainly a big and important factor. Mine is a daily driver. So easy starts on a cold morning, I have remote start and don't need to pump or feather the throttle, runs smooth in all conditions, etc. And probably better MPGs (though not that important with an old Jeep), and easy tuning with a tablet or my phone via bluetooth.

 

[TrackRat]

I can certainly see going down that path in the future

 

[TSB8C]

Lots of experience among this group with different options when you're ready. Until then, good luck with the carb choices. Lots of good folks here to help with that as well (just not me ).

 

[Manic Mechanic]

I switched from the 2100 to the sniper and I've talked several customers into switching to it on there classic cars as well. One of the big reasons is a carburetor is open atmosphere and and EFI is sealed due to the higher fuel pressure. With the ethanol in the fuel it can and will tear up the seals in a carburetor even more so if sits for any length of time without running it. (Mine sits for a week or two at a time depending on my work schedule) I always kept my carb tune and clean but it was getting tougher each year as the fuel seemed to degrade faster. Now with the EFI I just turn the key and go no waiting for the fuel in the float bowl to burn off while the Jeep struggle to run on it.

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[Belizean]

I had a Weber Carb on a 4 banger and was pretty happy 95 % of the time. Since I got a rebuilt 6 258 with Sniper, it put me at about 200 %. I swear I have about 4 times the power also. Of course the 4 banger had 238,000 miles in the end. I’m pretty sure it was the MSD box that kept it running smoothly the last 80,000 miles. It creates a hot spark.