Hi all,
I've got a 1968 Dodge Monaco that has the 383 2bbl. and single exhaust. It makes good power, and I actually find it quite impressive for a 2bbl., but I feel the need for a four barrel. I realize Holleys are big with the Mopar crowd, but I'm a beginner and have more experience with Edelbrocks and they're easier to live with, so I'm probably getting one of them. I'm new to Mopars so my question is: what size to get, and what intake? I've done a bunch of forum searches on this stuff, but they seem to deal with much more heavily modified motors than mine.

This would be considered a very mild modification, as the cam and heads, etc. are all stock. I just want to put a nice 4bbl. and nice duals on it and I'll be happy. Would a 750 be too much carb for an engine like this? I had a 600 Edelbrock on an Olds 394 and it did the trick, but if I could get away with a 750, then I'd probably go that direction in case I mod it up more in future.

My first thought for intakes was to find a stock '68 4bbl. intake, but I've heard the flow on an Edelbrock performer is substantially better. Would I notice a difference for the extra $$? I'm not doing any drag racing, this is all street/highway stuff here.

Another consideration: if I get a 600CFM, and decide to put a hotter cam, headers, etc. on it later, will I be under-carbed?

Thanks in advance for any basic wisdom you might have to share!

 

I believe the factory 383HP carb was 625cfm.

 

You're right about the 383 2bbl having good power and response. But, with an original 4bbl intake and the Carter 625 4bbl, you'll find that it'll have more legs on the top end. Lots more legs as with the 2.76 or 3.23 rear ratio, you should be able to bury the speedo into the 120 mph area. The Edelbrock Performer is a good intake manifold/carb combo and is what I have considered for my '68 Fury when the time comes as I have had them in the past and they have always worked well.

If you split the exhaust, with the 2bbl.... it'll wake it up a bit!

 

M68 -

Gonna go along with the guys, a carb in the 600 - 650 range (tops) will give you the most response. The adage "Holley for the track and Edelbrock for the stree" has a lot of merit, but I haven't had any tuning or upkeep issues with my Holley yet.

The double pumpers will give you a better launch. but how much better with a stock cam might be debatable. For now a vacuum second would be the way to go, IMHO. And go for a good dual plane intake manifold. The Edelbrock intake kits might be a smart move.

Yes, adding full dual exhausts will help.

CFM isn't the only measure of a carb, and a 600 - 650 will handle a mild cam with zero problems (but you might have to play with the jets etc).

Archer

 

Double pumpers with highway gears and a auto don't work well. They are also very thirsty gas wise. I tried both on my 440 charger and the double pumper performed worse and dropped my milage by 3 mpg. They also are more expensive. I now have a 750dp as a shelf orniment along with a 1050 and several AVSs and 600 holleys.

 

Thanks for the replies, guys. Sounds like I'm after a 600 Edelbrock at this point. A local car parts store wanted like $400 for one(???) but Edelbrock online sells rebuilt ones for about $220, which is very doable. Does anybody know of a good place to find a good used Performer intake? I just find the cost of a new one to be kinda steep.

A few more things...I've been hearing people talk up the dual exhaust on 383s. I had duals on my Olds 394 and loved the sound, and I'd like to put some on the Monaco but what kind of power increase should I expect? A car friend told me that on an engine the size of the 383, duals wouldn't make nearly as much difference as they would on 400-455 sized engines, but I figured I'd ask here because Mopar engines seem to be in a class of their own.

Also, I've heard you can replace the intake manifold on a 383 with no coolant drainage required, just "bolt off, bolt on." Is this true? Is there anything special I should know about 383 intake swaps?

Thanks again,
Mack

 

To get the true gain from the 4 Bbl. you will need dual exhausts. Otherwise you won't notice much differnce.

 

As long as we're on the topic of dual exhausts...I figure I'll ask about a few more points, as I have very little experience in the area. I've heard yeas and nays on the subject of whether or not a crossover or X pipe would really make a difference with this engine. Would some form of crossover be a good idea? Does it make a difference whether it's an "H" or an "X," or where along the pipes the crossover happens?

 

If looking for a used duel plane I found ebay has some. Just have to keep checking. They are in demand.

I have a 383 with the 750 edelbrock. I do have a high performance cam. It works great. You would be smart to put headers on while your going to duels.

 

TTI is an exhaust manufacturing company that I have heard good things about regarding exhaust systems for our C-bodies. I plan on ordering from them when I change the existing 2bbl exhaust manifolds to the HP manifolds that I recently acquired.

I have looked through their site and they offer an "H" pipe as an option but, for some reason do not offer an "X" pipe crossover.

I recently had a full dual exhaust system installed, without a crossover, and installed a pair of 3-chamber Flowmasters. It sounds good and, like I said in an earlier post, woke her up a bit. When I make the modifications with the 4bbl and the HP manifolds, yes, I will install the "H" pipe crossover as I have heard good things about it and most of all..... It looks cool!

Here's a link to the C-body systems that TTI offers. Good diagrams, too!
http://www.ttiexhaust.com/Exhaust-H/ExhaustSystems.htm