318 dual carb help
 

Hi I am building a 318 from an old 68 cuda to drop into a 97 jeep grand cherokee limited. I wanted to get info on what needs to be done to install a dual 4 bbl carb setup. Do I need new intake manifold? If so what kind. Thanks

p.s. doing this on a budget but want some major power

if it be a street car, copy what chrysler did on the same engine. but note chrysler did NOT call the 318 a high performance engine. the ports in a 318 are small so big cam will be a thing of demising returns. if it was mine and a daily driver i would run a mopar p4452782 cam, 268 degree, .429 lift. and only run the primary plates of the carbs. two small 4 bbls is way to much air unless its a race engine. i ran a cam like this one in a 413 in a 300 L. good daily driver. no MPG loss from a mild new yorker cam. but 20 HP more.

Welcome.

Don't usually hear the phrases dual 4bbl carbs and budget in the same sentence.

If you want some tips for 318 performance on a budget your at the right place.

I've got to ask why you came up with the dual carb idea?

Sounds like a cool project. The idea behind dual carbs came during an era when large carburetors didn't exist yet. Drop one Holley 650DP on that 318 and forget about duals. Also, if you're on a budget why not start with a 360, it costs the same to build and with the 1:1 HP to cubic inch formula you get 42 free HP...just my 2 cents.

joey -

If you're putting 2 x 4V on a 318, you're doing it for looks, not performance.
In most applications an efficient single 4V / manifold will out perform a multiple carb system.

Archer

two 750 s

way too much carb Unless you are turning 10K RPM

My goal is just to build a 375+ hp 318. just throwing some ideas out there and thanks for all your input

This should get you going.

http://www.hotrod.com/howto/113_0304...d/viewall.html

http://www.popularhotrodding.com/eng...ar_318_engine/

just my idea. a 375 HP 318 will NOT be very streetable. but tons of fun. OH and go buy a oil refinery.

Im runnin near that right now very streetable so streetable iwas thinkin on increasing the lift on the cam ..swaping from my comp dual power too a voodoo cam
it depends on your combo
my last 318 I ran a 340.cam but the key to a hp 318 is heads
360 heads with stock valves will make incredible power ...mill .020,..050 off the head and corrosponding intake face if needed. Mine happen to be ported...too the max.
or port your 318 heads and stuff the biggest valves in them possible
LA blocks make a ram or supper charger effect at the valve because of the long rods so dont think velocity think.., air fuel being ramed into the cylinder when the valve opens
no large valves,are needed

i ran the 1968 340 4 speed cam in a 360. in 82 HD crew cub, ram TWK. about 5,000 lbs total. but stomped all over a stock powerstroke ford TWK. MPG 8-10 on a good day. thats the most cam i would run as a daily driver.

I ran a 86 ram van with a 360 curb weight 5680 ...my tools and suppies
ran a puple cam H 272 with solid lifters performer rpm 750 holli headers duals 4.11 gear with a 518 trany I retro fit in place of the 727 ...
10-18 mpg ....and faster than..lightning ...:gone: