got a 340 intake for my 318 RR...what next?

Posted By: bigdaddywiz

got a 340 intake for my 318 RR...what next? - 12/23/10 07:36 PM

I've been looking to do this for a while now and finally over the summer I came across an intake, 4bbl and air cleaner off a 340 (stamps showing its off a '72) for my 73 Road Runner with a 318 2bbl.

Now I know people are going to say why not just do an engine swap?...well, i don't have the cash to change out the transmission and rear end to handle much more power let along find an entire engine as well. I know this isn't going to make my car a fire breather or anything, I just want a little more pep, and something to do over the winter while its in the garage.

Can anyone offer any pointers for this project? I know the carb will need rebuilt, but didn't know if i had to re-jet or anything like that since this will no longer be on a 340 block. Also, what gasket kit will I need to get? This will be be my first engine project, but I wouldn't consider myself a total noob.

right now, the only thing done to the car is straight pipes with classic series flowmasters. stock headers, but i do have what looks to be aftermarket headers that my dad had lying around his garage. don't know if they will work, but I'm sure I'd probably want to add those on later if they do.

any pointers for this would really be appreciated!

Thank you.

Posted By: 1_WILD_RT

Re: got a 340 intake for my 318 RR...what next? - 12/23/10 07:51 PM

Back in the 70's I helped a buddy add a 70 340 intake, a Holley 600 & some Hedman headers to his 318/3spd Duster.. That car spanked some stuff it had no business running with... Like a 396 Chevelle & a 68 Camaro with a hotrodded 350 & gears..

Posted By: MoparforLife

Re: got a 340 intake for my 318 RR...what next? - 12/23/10 09:04 PM

Gaskets will be fine. Use the composite intake gasket - not the tin 318 type. The sealing surface may get some what marginal in places and you want a good seal.
Don't listen to all the nay sayers that will tell you that this won't work or that you should do this or that in stead. Hey it will work and work well. Just do it and have fun. Nobody can tell you where to jet - each will be different.

Posted By: deansrr

Re: got a 340 intake for my 318 RR...what next? - 12/23/10 09:30 PM

pretty easy change over, as stated above good gasket set, how do you know the carb needs rebuilt? what kind of carb?

Posted By: sthemi

Re: got a 340 intake for my 318 RR...what next? - 12/23/10 09:33 PM

I will assume you are replacing the tiny two barrel on the 318.
You will have to buy or fabricate the throttle bracket, since the original is in the wrong place., and if you are running an automatic, some tweeking of the kick down linkeage will be needed.
As far as the carb, it should be in the ballpark as far as jetting, the factory jetted them lean to begin with, for emmisions...
Just plan more fuel stops ! Not that the carb will burn more fuel, just your foot will be listening to the music more often !

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/23/10 09:42 PM

Quote:

I will assume you are replacing the tiny two barrel on the 318.
You will have to buy or fabricate the throttle bracket, since the original is in the wrong place., and if you are running an automatic, some tweeking of the kick down linkeage will be needed.
As far as the carb, it should be in the ballpark as far as jetting, the factory jetted them lean to begin with, for emmisions...
Just plan more fuel stops ! Not that the carb will burn more fuel, just your foot will be listening to the music more often !

yeah i'm replacing the 2bbl carb with the 4bbl that came with the intake, so its whatever came on a 340 in 1972. I'm pretty sure it needs rebuilt cause it was sitting in this guys garage for a long time and everything seems dry rotted, like its been sitting for 20 years or so.

about the bracket that i'll need for the throttle linkage and kick down...it looks like it was attached to the carb. i'm not looking at it at this very moment, but i think it was all there. will i still need to fabricate or will the 340's linkage and brackets work?

Posted By: sthemi

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 12:41 AM

The 340 throttle brackets should work.

Posted By: pinkduster

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 12:59 AM

This is an easy swap. I've done it a couple times. However, each time a new Holley 600 was used. I would always get a intake gasket set for a 340. I never used the end gaskets, just a bead of silicone. Each time, we were able to just bend the 318 throttle bracket over a little to get better alignment with the carb. (Not too noticeable.) We'd always have all the parts ready to go and we'd joke that we (a buddy of mine and I) could complete the swap on a running car before the engine even cooled down.

Posted By: scratchnfotraction

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 01:32 AM

it is very important to have the throttle pressure valve linkage to save the tranz from burning up

a 2-v linkage can be mod o fried to work with very little work

if it has a flat rod from bracket to the carb stud

you can bolt 2 of those together to make it longer from the bell crank to carb stud

if its round threded rod you can cut and weld a piece in to make it longer and still be adjustable

usally needs 1" to 1.5" added to the linkage to be long enuff

I also bend in a slight s curve to aline it up to the carn stud

it needs to move freely with out the carb lever and the spring pull it back with out open the throttle

stock 4-v linkage would be ideal,IIRC it would be the 3 rod style for A-body

it will be a boost in performance even with the 2-v wimpy cam in the 318

4-v and headers will wake it up some,cam swap later to gain some more performance

done this swap many times over the yrs

should be a thermo bog on that 340,I would have it rebuilt or go with another carb,they can be pricey and feniky to get right for a first timer

600cfm eddie carb works great on them,IMO

here is the 88 360 headed 318 4-v cop engine in my stepside

600 eddie carb
LD4B intake
lunati voodoo roller cam
headers
deul 2.5 pipes
a999 HS/LU tranz
8 3/4 with 3.23 gears

runs strong and knocks back 19 mpgs daily driveing

Attached picture 6374384-smallblockengine.jpg

Posted By: GO_Fish

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 01:50 AM

If your kickdown rod is the round threaded kind, the 2bbl version will be too short to reach the carb as said above. Edelbrock sells a cheap threaded extension a couple inches long to correct this problem. Summit sells them, they come in two different diameters depending on which diameter threaded kickdown rod you have. You will be happy with the upgrade. The Thermoquad spread bore carb you probably have will have an agressive sucking sound when you crack the secondaries open!

You may not have to re-jet the carb, just clean up and re-gasket if you are half lucky.

Posted By: skullbucket

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 02:01 AM

Quote:

Back in the 70's I helped a buddy add a 70 340 intake, a Holley 600 & some Hedman headers to his 318/3spd Duster.. That car spanked some stuff it had no business running with... Like a 396 Chevelle & a 68 Camaro with a hotrodded 350 & gears..

Uh well..... uh..... yea....
Here here have some more eggnog, I'll know when you had enough when the 318 whipped on an L-88 vette also!!!!

Posted By: 1_WILD_RT

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 02:37 AM

Quote:

Quote:

Back in the 70's I helped a buddy add a 70 340 intake, a Holley 600 & some Hedman headers to his 318/3spd Duster.. That car spanked some stuff it had no business running with... Like a 396 Chevelle & a 68 Camaro with a hotrodded 350 & gears..

Uh well..... uh..... yea....
Here here have some more eggnog, I'll know when you had enough when the 318 whipped on an L-88 vette also!!!!

Believe what you want... I was there... To be honest I was completely shocked too...

Posted By: scratchnfotraction

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 03:16 AM

i have seen a few little teens that could also

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 07:18 AM

Quote:

it is very important to have the throttle pressure valve linkage to save the tranz from burning up

will this be something i have to buy separately or can i make either the 318 or 340 linkage work?

thanks, and sorry if this is obvious...got lots to learn!

Posted By: JoesMopar

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 07:24 AM

Quote:

Quote:

Back in the 70's I helped a buddy add a 70 340 intake, a Holley 600 & some Hedman headers to his 318/3spd Duster.. That car spanked some stuff it had no business running with... Like a 396 Chevelle & a 68 Camaro with a hotrodded 350 & gears..

Uh well..... uh..... yea....
Here here have some more eggnog, I'll know when you had enough when the 318 whipped on an L-88 vette also!!!!

Haven't even been a member for 2 weeks yet and already bashing people you don't know? Nice.....

Posted By: DaytonaTurbo

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 07:26 AM

If you can swing an intake change, can you swing a little more for a cam change? The summit k6901 cam/lifter kit is only 110 bucks and I'm sure someone on here can suggest a set of valve springs. Add in a set of aftermarket headsers and you'll really wake that 318 up a lot more than just doing the intake.

Posted By: rtidd440

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 08:09 AM

Quote:

If you can swing an intake change, can you swing a little more for a cam change? The summit k6901 cam/lifter kit is only 110 bucks and I'm sure someone on here can suggest a set of valve springs. Add in a set of aftermarket headsers and you'll really wake that 318 up a lot more than just doing the intake.

Did this years ago with a 69 Charger. Someone put a rumpy cam in it and left the two barrel on it before I got the car. Put on a stock spreadbore manifold with a TQ. Ran real good for a 2 ton car.

Posted By: rattler

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 02:19 PM

Back in the 70's i had a 70 model duster with a 318. I replaced the intake with one from a 273, put an AFB carb on and installed a stock 69 model 340 cam with dual exhaust. This made for a fun little car. I to surprised several bigger name cars. And as far as beating up on chebys, remember its just another cheby.

Posted By: T2R9

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 03:39 PM

Quote:

If you can swing an intake change, can you swing a little more for a cam change? The summit k6901 cam/lifter kit is only 110 bucks and I'm sure someone on here can suggest a set of valve springs. Add in a set of aftermarket headsers and you'll really wake that 318 up a lot more than just doing the intake.

I have run this cam on two different 318's with stock springs with no problems up to 5500 rpm. My 76 Feather Duster with this cam, a 72 340 TQ and duel exhaust was a screamer! The 4-speed and 3.55 gears helped too!

Posted By: scratchnfotraction

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 03:44 PM

if you have the 4-v 340 linkage use it

it basicly the same from the intake bracket down to the tranz

the longer piece will be from the bracket to carb rod

you can mod the 2-v linkage to work with ease,just ask on here when you ready to do it

see if you can post pics of whats on the car now and what peices you have from the 340

I have a few pieces that might help you get it done..they are free so it should be cheap for you to get it right

sounds harder than it is,but its one of the most important pieces on the car for tranz longevity and working correctly on the shifts

if you go junyarding any of the mid 80s 4-v cars F-R bodys( 5th aves-gran furys) would have a set up to use also..as long as its a 3 piece...just get all of it

some of the mopars use a one piece rod also,but it goes by body style

when I did my truck to stock q-jet,I just got the intake carb linkage all the way to tranz

when I went to LD4B and eddie carb stock linkage worked

there are some aftermarket cable set ups that are good also(bouchillon/lokar)

lets see what you got

Posted By: Mopar_Country

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 03:49 PM

I did the same swap, you should get the throttle bracket from the 340 as well and the upper portion of the throttle pressure linkage. You didn't say what carb, is it a TQ? I run the 340 intake and a large primary TQ on my teen and it runs great. I also did a cam swap and headers. Composite gaskets for the 340 intake. Just make sure your surfaces are clean and dry. On the ends I took the cork gaskets and set them on with black rtv and put a little weight on them and let them sit overnight. Then I put a bead on top before installing the intake, it worked great and no leaks. After installing everything make sure that at WOT your lever on the trans is all the way back but not putting undo pressure on the lever.

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 05:18 PM

thank you so much for all the tips! i will check and see exactly what kind of carb i have when i get home. should i look for any specific markings?

Posted By: scratchnfotraction

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 05:40 PM

cant miss a thermobog,,it has a plastic bowl center section

and is preety big looking

AFB will look like and edelbroke carb..maybe not as pretty

Q-jet looks like ...well a q-jet

I like running a q-jet on all my 318s myself and mopar did use them..so you can find one with a mopar throttle lever too

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 06:31 PM

looks like its a Holley...

Attached picture 6375610-1224001124a.jpg

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 06:32 PM

and another shot of it...

Attached picture 6375612-1224001124.jpg

Posted By: MoparforLife

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 06:32 PM

Looks to me like you will need a carb.

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 06:35 PM

Quote:

Looks to me like you will need a carb.

i wont be able to clean that one up and get it rebuilt?

Posted By: scratchnfotraction

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 06:36 PM

at least a good soaking and rebuild kit

move the carb and lets have a look at the intake

is it a spredbore intake?

is that holley a spredbore carb?

what are the list #s on the airhorn/front driverside?

if not a spredbore did it have a square to spredbore adaptor?

Posted By: scratchnfotraction

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 06:39 PM

thats a nice 340 aircleaner

need to put that recpt and cover back on the box..thats troble waiting to happen

Posted By: 1_WILD_RT

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 06:40 PM

Quote:

at least a good soaking and rebuild kit

move the carb and lets have a look at the intake

is it a spredbore intake?

is that holley a spredbore carb?

what are the list #s on the airhorn/front driverside?

if not a spredbore did it have a square to spredbore adaptor?

That is a speadbore Holley.. Mechanical secondaries = 4 mpg... Find a Thermoquad or a Mopar OE Quadrajet..

Posted By: MoparforLife

Re: got a 340 intake for my 318 RR...what next? - 12/24/10 07:15 PM

You sure that that carb hasn't been through a fire. Maybe it is the picture but it looks to have been real hot at one time. Not good in my opinion.

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 02:01 AM

Quote:

If you can swing an intake change, can you swing a little more for a cam change? The summit k6901 cam/lifter kit is only 110 bucks and I'm sure someone on here can suggest a set of valve springs. Add in a set of aftermarket headsers and you'll really wake that 318 up a lot more than just doing the intake.

i'd love to do that down the road, but wouldnt i have to change out the 904 tranny and 8.25 rear to handle the extra power? how far can i go?

Posted By: scratchnfotraction

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 02:48 AM

no you dont have to change traz or rear axle

they will take a little HP upgrade

run them till they break then swap to bigger stuff

comp 901-16 springs are good for most cams that are a mild hydro cam,they are a single with damper,drop on with heads on engine,use stock valve seals and retainers

I steped mine up to a small roller cam with the 901s and run the 904 tranz with a high stall loc-up verter

Posted By: DaytonaTurbo

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 02:56 AM

Quote:

Quote:

If you can swing an intake change, can you swing a little more for a cam change? The summit k6901 cam/lifter kit is only 110 bucks and I'm sure someone on here can suggest a set of valve springs. Add in a set of aftermarket headsers and you'll really wake that 318 up a lot more than just doing the intake.

i'd love to do that down the road, but wouldnt i have to change out the 904 tranny and 8.25 rear to handle the extra power? how far can i go?

You're not making that much power for it to be an issue. Also one thing you should really look into is what rear end gear ratio you have. 2bbl 318's tended to come with granny rear end gear ratios. Gears like that make for nice highway cruising but will make your car an absoloute DOG in the acceleration department.

Quote:

Quote:

If you can swing an intake change, can you swing a little more for a cam change? The summit k6901 cam/lifter kit is only 110 bucks and I'm sure someone on here can suggest a set of valve springs. Add in a set of aftermarket headsers and you'll really wake that 318 up a lot more than just doing the intake.

I have run this cam on two different 318's with stock springs with no problems up to 5500 rpm. My 76 Feather Duster with this cam, a 72 340 TQ and duel exhaust was a screamer! The 4-speed and 3.55 gears helped too!

That's very interesting. If the stock springs will do it to 5500, assuming they're in good shape, that sounds like a good bet. Stock 318 heads are going to be done by 5500 anyway.

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 03:04 AM

Quote:

You're not making that much power for it to be an issue. Also one thing you should really look into is what rear end gear ratio you have. 2bbl 318's tended to come with granny rear end gear ratios. Gears like that make for nice highway cruising but will make your car an absoloute DOG in the acceleration department.

ya know, i have no idea what gears are on the car, but i dont think they are the granny gears. its got decent pull from a dead stop even with its whopping 190 hp!

what other gears did they put in the 318s?

Posted By: scratchnfotraction

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 03:12 AM

2.76,2.94,3.21,3.23.3.55,3.91 depends on what was orderd when new

most have a 2.76 open diff

3.55 are good for the street

3.91 are better but can get old on the highway

pull the rear cover and change the oil,probly needs it anyways..while its draining turn it to see the yr and gear ratio stamped on the ring gear

few bucks for 2 bottles of gear oil,that info is cheap and will be needed down the road with upgrades...also will know if its open or a sg unit

a short dur cam with high lift works great in a teen for street duty..gears multiply the torque and HP so the lower the better for launching it from stand still

Posted By: DaytonaTurbo

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 03:22 AM

Jack the back end up and count how many times the driveshaft turns for one complete revolution of the rear tires. If you have a suregrip you'll need to jack up both rear tires, if an open rear diff only jack up one tire. Take a marker and mark your driveshaft and tire when you start to rotate it so you can keep track.

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 03:30 AM

Quote:

2.76,2.94,3.21,3.23.3.55,3.91 depends on what was orderd when new

too bad my dad doesn't remember...he's the original owner! i always get on him for getting the "base" model...he sold a 1970 340 duster for a 318 road runner! i've attached a pic in case you were interested.

Posted By: mopargem

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 03:54 AM

Even with the 318, its probably a 3.21 since its a road runner, thats what one of my brothers 74 came with. Unless you can hook up with slicks, you will never hurt that 8 1/4 rear. I've done the bone stock 318 then cast intake 4 bbl with sq bore eddy carb/adaptor swap with headers and its makes for a quick reving, plenty of street power and great sounding combo on a budget. Nice looking car

Posted By: forphorty

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 05:25 AM

Quote:

Quote:

2.76,2.94,3.21,3.23.3.55,3.91 depends on what was orderd when new

too bad my dad doesn't remember...he's the original owner! i always get on him for getting the "base" model...he sold a 1970 340 duster for a 318 road runner! i've attached a pic in case you were interested.

Posted By: scratchnfotraction

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 01:49 PM

thats a nice looking car

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 04:41 PM

Quote:

thats a nice looking car

thanks man!

Posted By: MoPar Jamie

Re: got a 340 intake for my 318 RR...what next? - 12/25/10 10:10 PM

That IS a nice looking car. I swapped an '84 4-v intake onto my '75 shortbed and it made a ton of difference. I'm running an Edelbrock 600 carb. Otherwise its a stock '83 318. I am running a 4-spd with OD so I didnt have to mess with the kickdown but the cable and bracket are stock 318-2v parts.

I used a cruise control holddown on my truck with the cable going through the vertical part to get the cable where it needed to be. I also flipped it around and its angled toward the drivers valve cover.

I am also running and 8 1/4 rear and the 4 gear is much more violent on it than an auto would be so I think you will be fine, same deal with the trans. Those tranny and rear combos were used on 360 R/T Aspens BTW so they can hold up to a bit more power than a person would think.

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/26/10 04:29 AM

here are a few more pictures of the intake and carb for those that wanted to see them...

Attached picture 6378244-1225001320.jpg

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/26/10 04:30 AM

more...

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/26/10 04:31 AM

more....

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/26/10 04:32 AM

and one more...

Attached picture 6378249-1225001334.jpg

Posted By: scratchnfotraction

Re: got a 340 intake for my 318 RR...what next? - 12/26/10 04:37 AM

that carb is most likly a thermobog replacement holley

spredbore,manual 2ndarys,double pumper

the intake will fit a q-jet/thermobog/spredbore holley carb so you have some choise on waht carb you want

or a spred to square adaptor will fit an eddie/carter/square holley

itakes fine,carb looks like it need a rebuild

Posted By: bigdaddywiz

Re: got a 340 intake for my 318 RR...what next? - 12/28/10 06:00 AM

so can anyone recommend a gasket set that will work with this particular carb?

Posted By: Orange_Duster

Re: got a 340 intake for my 318 RR...what next? - 12/28/10 10:30 PM

That appears to be list #6711.It takes holley kit 37-605.Shoud cost about $35-$40.