(Another) 383 2 bbl to 4 bbl conversion thread, anyone got a parts list?

[HOTTODDY6757]

Same bolt pattern for the "Holley" pattern (adopted by all for 1968 model year Chryslers) as the spreadbores. The spreadbores have the unique sizing for the secondary throttle plate sizes.\

You WILL also need an air cleaner with the 1968 Holley diameter air cleaner base hole. Which is the same as any other later Carter or Holley 4bbl. IF you can find an air cleaner base section with the big-enough center hole, you can then trim the outer section off and have an incognito open element air cleaner using your existing factory 2bbl/4bbl top.

The Edelbrock DP4B aluminum intake of 1968 came with a Chrysler part number cast into it, so it was legal in the stock classes for drag racing. Mounting plate height might be a bit different, but not enough to place the top of the air cleaner stud above the cowl level on the body. I have a Torker 383 on my '67 Newport with no issues. I suspect the Performer 383 intake is an version of that earlier intake, with some updates and tweaks.

Linkage? Main thing is that the throttle shaft of the primary side will be more forward on the engine than the 2bbl is. Might be able to loosen the throttle cable and reposition it a bit more forward in the holder, then gently tighten it down? Remove and use the existing throttle stud after getting the necessary Chrysler linkage adapter on the new AVS2.

The transmission rod will similarly need to be longer. Edelbrock lists such an extension in their catalog. Just screw it onto the existing rod and attach the front part of the rod (threaded end) onto it and adjust as normal. Before you do anything, check the current adjustment on the rod (turns preload, lengthening, from when the end of the slot just touches the throttle cable stud) at hot base idle. Adjust the lengthened rod like that. If the transmission shifts are too soon, add another turn of preload to get things back to where they used to be.

Edelbock and Holley both advocate for their square-bore adapter for the spread-bore manifold. I discovered that with the thick insulator OEM-style base gasket (rather than the thinner paper one that comes with the carburetor), that adapter is not needed. Find an insulator gasket (thicker and with the plastic bushings in the mounting stud holes) for a '70 383 4bbl (which was also a factory AVS) and you'll probably find that the rear areas have enough stiffness and size to reliably seal the rear of the carb to the intake manifold. I did that on a similar situation and it worked fine for over 500K miles. DO check this first, before buying the adapter kit, which will further add to the ultimate carb height on the engine! On my spread-bore intake, there was about 1/4 of excess gasket which covered the spread-bore secondary throttle contours.

You many need some additional wire to power the electric choke. You can incognito run that wire along side the wires going to the distributor on the rh valve cover, then to the cowl's other wiring toward the driver's side of things.

4 carb studs and nuts might come with the new carb. Those studs are very soft, so I like to replace them with the "black" studs from an auto supply, which are much harder. Put a bit of oil or anti-seize on the part that goes into the manifold.

You can re-use your existing valley pan gasket, if desired. Either way, get the 1969 440 6bbl paper gaskets, too, or a new valley pan which has them for your engine size. The paper was added to keep the metal valley pan beads from embedding into the softer aluminum of the one-year aluminum manifold on the 440 6bbl motors. Fel-Pro makes those paper additions AND might include them with their new valley pan gaskets for which ever engine size you have.

For a sealing upgrade . . . I take some black, high-heat sealer and put a skin coat on the paper gaskets and fill the bead on the valley pan gasket with it, too. Scraping it flat with a gasket scraper. Let it all cure for 24 hours and install. Has worked great for me. Might be over-kill, but so is a "higher degree of execution", many times, too.

1-Edelbrock Chrysler throttle cable adapter Edelbrock 1481
1-Edelbrock transmission rod extension, note diameter of your stock rod 5/16" rod Edelbrock 8004
1-Edelbrock thick carb base insulator gasket (with bushings) Edelbrock 9266
1-Air cleaner items mentioned above
1-Wire and quality terminals for electric choke connection
1-Black finish stud/nut kit (longer than supplied with carb and harder metal) Edelbrock 8056
// I had problems finding these items in the current online catalog, so went back to a 2019 catalog I had downloaded. Should be the same part numbers, I suspect. The noted car studs might be cheaper if sourced locally? //

Take care and enjoy!
CBODY67

I just had all the parts delivered from Summit & Pypes to do my conversion to 4 barrel on my 66 Dodge Polara. I see some extra linkage I need from your post. 2186 Edelbrock intake, Hooker Headers because none of the manufactures make the first exhaust pipe any more. Is there that big of a difference in C body & B body front end parts? I found that Pypes when I asked about they complete exhaust they have one for headers crossmember back with turbo mufflers. I am also installing the single to dual power master brakes. I am hoping this upgrade will have few problems. Ha Ha LOLROF. Before picture on my 383ci with 51,000 miles survivor. Thanks for the information

 

[Gerald Morris]

.... Is there that big of a difference in C body & B body front end parts? ....

Yes, the difference is that C bodies weigh about 1/4 ton (or more) MORE than B bodies, and REQUIRE HEAVIER, STRONGER, LARGER PARTS! Don't even play with the notion of using stuff meant for B body weight and proportions.

For front end suspension, stick with stuff meant for C body scale machines. Interestingly enough, I learned that the early Dodge RAM pickups, say, late 1970s through early 1980s use the same disc brakes and accoutrements up front as the "Formal" (late 1970s) C body Mopars. I don't care for 1970s cars, period, so this is of little interest to me aside from demonstrating that, contrary to the profit motivated assertions of "Break Masturbator" type "brake specialist" shops, A VALID FRONT DISC BRAKE SYSTEM USING MANUAL POWERED MASTER CYLINDERS WAS USED BY DODGE ON THEIR EARLY 1980S D150 CLASS PICKUPS!!! Suffice to say, my hostility to needless booster systems which fail as soon as the engine dies has valid underlying reasons.....

Modern enhanced front end suspension companies abound. PST comes to mind as one. Just stick with what's engineered for C body cars and you probably will live when you hit the highway.