2 barrel to 4 barrel?

[SirDan]

Ive got a 73 318 with a 2 barrel on it. the car is also an auto trans. I found out i actually have a ld4b sitting in my basement. I also have a 600 cfm edelbrock performer carburetor. Id love to bolt these on and have some fun with them but Im unsure of what throttle, kickdown and fuel line modifications might be needed. any help is appreciated.

Oh and i know the ports on the intake are larger than the stock 318 heads.

 

[HemiEd]

Probably won't see much improvement to anything but the cool effect, unless you improve the exhaust flow, and ultimately the cam.

But it sure won't hurt anything, and the Eddy is probably fresher than the old 2 barrel.

 

[68cuda]

Here's a partial answer:
The throttle linkage rod will have to be lengthened at the carb - Edelbrock actually sells an extension for this. I'm running an Edelbrock Performer manifold with the 600cfm Edelbrock carb on my 318 and I had to weld an inch and a half extension into the throttle linkage rod to get the kickdown to work properly.

You can check this by going through the kickdown set up procedure in the Factory Service Manual. If you can't get it set properly with the linkage hooked to the 4 barrel, see if it will set up with the linkage disconnected from the 4 barrel. If that works, you will be able to see and measure the amount the throttle linkage rod needs to be lengthened.

 

[dano]

Might check to see if you'll have a port mismatch with the intake. Honestly, if the car runs good, save your goodies for when you do a rebuild. If the motor is a stock rebuild, you'll need to know a few things like static compression ratio, converter size, gears, etc to spec a cam to go with your intake and carb to see a gain. I guess it all depends on what you intend or are doing with the car?

 

[furz4]

You will at least want a dual exhaust if your not running one already to see much improvement. I have done this swap a couple of times and you can adapt the 2BBL linkage to work by extending the kickdown and throttle linkage. Make sure at full throttle the kickdown is also all the way back. Like Hemi said the cam will realy hold you back but with a good exhaust you should see some improvement.

 

[SirDan]

Ive allready got dual exhaust, i have a 340 cam to put in and hopefully ill be getting headers to put on if i win this ebay auction. Im also going to convert to a 4 speed, im fairly positive i now have every part and i will work on putting it in very soon.

Thanks for all the answers it doesent sound too bad at all.:-D

 

[RustyRatRod]

There will be a port mismatch on the intake/heads. The LD4B is 340/360 sized ports. the D4B was for the 318.

 

[66fs]

There will be a port mismatch on the intake/heads. The LD4B is 340/360 sized ports. the D4B was for the 318.

Ports are the small 273 and 318 size on the LD4B and D4B. The D4B is for the "64" and "65" 273 with the 5/16 intake bolts. LD 340 is for the large port 340 and 360 heads. You should be happy with your combination, but I'd add 340 valve springs and a double roller timing chain.

 

[dano]

Ditto on a fresh quality timing chain. The Timing chain guide from Mopar works great along with as well. Just break the cam in correctly and you should have a good little motor.