318 4 barrel question.

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dvorak

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First off I am not a mechanic so this will be an easy question for most of you.

I have a 318 in my Valiant that has a 2 barrel on it, we are wanting more power. I have a 85 cop car with the 4 barrel intake on it. I am thinking about putting the 4 barrel onto the engine. Is this going to work as I want it to, or am I looking for trouble? Any help is appreciated, but remember I am not a mechanic so if I ask stupid questions about your answers please bear with me.
Thanks
Roger
 
Its a straight bolt-on. Take pictures of how everything is orientated on the 4bbl engine and swap it over.
 
I couldn't have said it any better. Take alot of pictures and raid everything on the 4bbl car for the swap. Just take note and care to adjust the tranny linkage so it will shift the trans in the car as normal. NOT hooking it up will destroy the trans in less than 40 miles. You'll have a pan full of mush if you don't hook it up. Take note how it shifts now and try and copy it after the swap is done. You'll be fine.
 
The 318 4bbl motors used 360 top ends, meaning heads and intake. Athough the intake will bolt on and it will be an improvement from the 2bbl, but the ports on the intake will be larger than the ports on your heads so it won't be a complete match.


Chuck
 
340 MOPAR, That is what I heard, but was not real sure of. Now is it really worth my time than to do this, or should I just leave it alone.

I will have to do some checking on the tranny linkage, I am used to the newer stuff, not the pushbutton auto. I will probably wait until after summer to try it anyway, you don't want to tear the convertible apart in the summer.
 
It should be an easy swap. You'll need the intake, carb, air cleaner and throttle cable, possibly kickdown linkage etc.

Without a free flowing exhaust it'll lack some power but it will be an improvement for power overall. Gas mileage will not be so great so keep your foot out of it.
 
First off the 85 engine does not run bad, but the 318 in the valiant has low mileage on it, like 5000 miles. Teh other one is in a cop car so I am going to guess it has ALOT of miles on it, but being a MOPAR would not hurt anything. I am going to guess the intake will be swaped out and I might even take the heads off of it and swap them. Keep the opinions and tips coming.
Thanks
 
Check the numbers on the cop car heads. I'm not sure, but they may be the 302s. If they are, you definitely want to grab those and get them done up. They have a smaller chamber size and will up your compression. I'm getting ready to install a set on my 318. You should also look around for an Edelbrock Performer 318 intake or equivalent. I see a few on Ebay for cheap. Get that and port match it to your heads and you'll feel the difference. JMO, MIKe
 
u might hunt and peck the e-bag or parts for sale ads for an aluminum intake like the Holley Streetmaster or Eddy LD340. There are a few OLDER intakes with smaller ports that work well with the 318. others will probably chime in with a few. they still show up once in a while.

if i were going to pull those heads off the 85, i'd want to mill them a bit. .040 or so? might be the best bet to cc them and shoot for 58-60cc of actual combustion chamber volume.

how far in the hole are the pistons on the engine u want to 4bbl?

sb
 
I did an 86 Diplomat cop swap to my Dart Sport commuter car.
Engine ,trans AND rear.
The good thing about the wider rear is that it looks right under the sheet metal.
Duster bodies always had that puckerd up look to me cause they used the same rear under the Darts and Dusters.
I took pics of moving the spring perches and setting pinion angle. I offered the "how to" free to Mopar Muscle. No takers.
If you use the cop 318 you can also use the lock up torque converter trans. maybe.
I like mine. I get 23 mpgh out of the car.
Of course, I used a different Q-jet cause the cop engine had the electronic one which I didn't want.
I had to change the lever arm on the carb. over to get the geometry correct on the trans linkage. (like the person says, must be right)
My experiance (opinon) is that the 85 318 will be the better motor. Maybe heads???
And cop departments sell cars before they get many miles on them. But they may have Idled a lot.
I just put a new oil pump and timming chain on it. Worked good last long time.
 
If the 85 has the 302 heads use them.Nice little performance head.Or just stick with the stock heads and add a 4bbl intake.

I would not use the 85(smog) intake.

Go for a edelbrock performer.

Then use the 85 4bbl linkage.Your throttle cable will be fine.

Here are some pics of my 4bbl swap on a stock 318.

Picture 274.jpg


Picture 404.jpg


Picture 405.jpg
 
Keep in mind the cop car motor will probably have the 360 style heads on it, which means large combustion chambers - low compression when swapped to another 318 depending on the deck height of the pistons. I doubt the cop car had much compression with those heads anyway.

A better plan would be to use the 302 casting head (if thats what happens to be on the cop motor), with (as someone suggested) an eddie performer intake. The stock eddie intake has small ports that match up pretty well to stock 318 ported heads anyway, and they can be found cheap on ebay or at swap meets. Id use an afb 4bbl as well, for simplicity sake.

The other thing to get from the cop motor is the complete kickdown linkage and throttle brackets springs etc (from the carb down to the trans lever), save that stuff and use it to swap onto the valiant when you change over to the 4bbl, that way you have a complete matched set. Those kickdown set ups are a mess to locate in a complete fashion.
 
Most correct, the 4bbl. 318 has 360 heads. For a cheap power upgrade like he is asking about since it is on hand, the 4bbl. will work just fine. Now;

IF he uses the 360 heads with the intake on the 318, a milling would be good to do. Enter other bolt hole alignment issues and possible port matching alignment.

IF he keeps the 318 2 bbl. heads, the port match will be off. A cheap way oput is to have the intake side of the heads window enlarged.

The mismatch ethier way isn't an end all item, but nice to avoid since it is apart. Of course, this is a price worth pending, ..... whats in his pocket? If it is zero dollors and cents, the the simple bolt on is fine as is and can not be knocked.
(I'd use the 360 heads bone stock.)
 
Well it is almost time to tuck the convertibla away for the year and this winter looks like the time to do this change on the engine. Right now I am leaning towards getting the heads off the 85 engine to a machine shop to have them gone through. I have even started to look for an aluminum intake for the engine. I am not sure what to look for there, so it is kind of a slow look process. Hopefully by the time I can drop the top next year I will have a little more power under the hood.
 
dvorak said:
Well it is almost time to tuck the convertibla away for the year and this winter looks like the time to do this change on the engine. Right now I am leaning towards getting the heads off the 85 engine to a machine shop to have them gone through. I have even started to look for an aluminum intake for the engine. I am not sure what to look for there, so it is kind of a slow look process. Hopefully by the time I can drop the top next year I will have a little more power under the hood.
Click to expand...

I hear ya!

I would go with a aftermarket intake for sure. I like the Mopar ones but they are pricey. Edlebrock are just as good.
 
do you have dual exhaust on the car yet??

if Not I would add duals Before adding a 4bbl;

duals with a 2bbl will add a bit of torque, and great throttle response.

:)
 
Ya there is dual exhaust on the car allready, that sounds good. That is one of the main reasons I would like more power. It sounds and looks good, but if you punch it at the green light it just does not want to move like you think it should.
 
Ok I was looking through Summit online and came up with this part number for an intake. EDL 21761 Would this be the intake I would want if I go with an aftermarket one? Also my next question is going to be if I went with a new carb what should I put on it, size wise? Thanks for all the help guys, I usually just put them back together and get tehm to run, never usually add any power.
 
That intake is a daul plane called the "Performer?" The yes, for a mild to peppy 318, that would be it.

On a carb, the stock (small) T-Q is a good choice or a aftermarket carb of not more than 650 cfm will do fine. 600 prefured for performance applications.
A stock 318 with just headers and intake can use a 500 cfm unit very well.
 
The preformer is the one you want like Rumble said. I would also suggest upgradeing the cam. The popular choices for your setup seem to be the Comp Xtreme 262 or 268. you would also need the Comp 901 springs with that. While your at it a double roller timing chain.
I have done this to my 318, and the cost is not that great, I am on a strict budget, if you fallow this, i think your best carb choice would be in the 600 cfm rage. Also buy some headers (not sure if you have those or manifolds). Most will suggest TTI. These are by far the best but are really exspensive. They fit like no other and will not scrape on the bumps.
another choice, that is a little less, is the Doug's. The to fit great and look good. Still a little pricey. Best bet, on a budget IMO, would be Hooker Comps.
 
Ok guys it has been awhile since I looked at this post, but I am looking at getting the Performer 4 barrel intake for the Convertible, now I have another question. With adding teh 4 barrel and hopefully getting a little more poer out of it will my tranny hold up? It is a pushbutton tranny and I do not know how tough they were built. I hate to put this on the engine and end up tearing the tranny out. Thanks for all your help so far, maybe some day I will even get this project done.
 
I would not be too concerned about the trans. If its working okay leave it alone.

One other thing I have learned about early a bodies and the kickdown linkage. you may find that you will have to cobble the linkage somewhat to make it work. The style used on the later model - 67 or 68 and up is different than the 66 and older. There is a clearance issue on the older a's underneath by the kickdown lever on the trans - its damned tight in there and the later model system may or may not fit.

I ended up installing a bouchillon performance kickdown to make it work on my 66. Hope this is helpful.
 
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