318 2bbl manifold swap with OE cam - worth it?

[rmchrgr]

Alright, I went to the track yesterday and ran my car - the only word I can find to describe the performance is PATHETIC. I'm too embarrassed to even post what it is.

Clearly the two main things (besides the low compression and exhaust manifolds) holding my 318 back are the 2bbl carb and the oe cam.

I'm thinking like anyone else who's had one of these dogs - put a 4bbl carb and Edelbrock manifold on it to wake it up. These are time-honored bolt ons. They must be ok for something, no?

My question is this - is it actually worth doing with the wimpy stock cam?

Here's the thing. I AM NOT going to pull the engine. I know all about the pros and cons of 318 vs. 360, how they all grow on trees etc. Let's just say my only choice at the moment is to leave everything AS IS and the only thing I can do is to get a manifold and Holley 4bbl for the time being. Distributor is staying (points) exhaust manifolds are staying (though it does have a dual exhaust with an H pipe and Flowmasters) and oe cam is staying.

I'm thinking LD4B (they can be found fairly easily as far as I can tell) and Holley 80454 which if I'm not mistaken is a Mopar-specific 600 CFM carb. To me this would be the easiest and least expensive route. Those carbs new are like $180 or so. I figure this all adds up to around $350 - $400 bucks including all the misc. parts need to complete the job though I could be wrong either way.

In my little brain, I'm thinking there HAS to be a better induction path than the cast iron manifold and 2bbl carb. The low performance is killing me! I'm hoping the minumum of tinkering will net me some seat-of-the-pants satisfaction. I once had a 273 in a '67 Belvedere with basicallly a manifold and Holley carb. Ran OK.

Thoughts appreciated.

- Greg

 

[flyfish]

A performer manifold would help, but I would go with a Holley 650 vac secondary carb (not the one with one fuel inlet) unless you're thinking about making it a performance machine down the road...if that’s the case, I would make it a Holley 650 dp.

 

[rmchrgr]

A performer manifold would help, but I would go with a Holley 650 vac secondary carb (not the one with one fuel inlet) unless you're thinking about making it a performance machine down the road...if that’s the case, I would make it a Holley 650 dp.

I think the LD4B was an ancient predecessor to the performer. I've read lots of good things about it and it's sized correctly for the 318. The Holley 80454 is a 600 cfm vac. secondary/electric choke carb.

My plans for down the road a way different - I have a 340 block that will get a a 4" crank, so it's like apples to oranges. This is 'just for now' to have a littler bit more fun and not be so wimpy when they flash my time up on the score board!

 

[Woodys_Cuda]

Agree with above.

I put a factory 4 barrel intake, with a thermoquad on my low comp 318, years ago. It made a nice difference, and was a cheap upgrade. The need for more speed took me to a 340 when I had a few more bucks.

 

[doktor_x]

I put an LD4B and a 600 cfm vacuum secondary Holley (80457 if memory serves) on an otherwise-stock 318 and it was certainly worthwhile. I can pass stuff with far greater ease and it takes less pedal to maintain speed. I'll still be doing a cam swap at some point though.

 

[rmchrgr]

Cool, thanks guys. So it seems like a worthwhile deal to bolt a manifold and carb on an otherwise stock engine. Everyone does this, it's been the thing to do for a long time. It's just that the oe cam in the 318 2bbl engines is so lame, it hardly turns over what seems like 4K.

 

[furz4]

I would upgrade the cam for sure I put a 4bbl on a 318 once wih duals it helped some but was still not much more then the 2bbl the duals helped more. The last 318 I did in the dart I have I changed the cam too, a huge difference revs all the way to 6 K now and I get better millage too. You can easily get 100 more hp out of it over stock with bolt ons but you need more cam. I am using the stock 340 cam but there are alot of newer disigns that are way better. Your probably leaving 50 hp on the table with that little cam.

 

[RedFish]

Now would be a good time to ask... How many of you will admit that you bolted a bunch of easy to do performance stuff on a high milage engine ( over 70K ) , only to have the bottom end come apart in less than 20K more miles ?
My suggestion would be leave the hood closed and stay off the track until you have a complete fresh engine to bolt performance goodies on.

 

[GTGrinly]

Now would be a good time to ask... How many of you will admit that you bolted a bunch of easy to do performance stuff on a high milage engine ( over 70K ) , only to have the bottom end come apart in less than 20K more miles ?
My suggestion would be leave the hood closed and stay off the track until you have a complete fresh engine to bolt performance goodies on.

Everytime I ever tried bolt-ons, was either the bottom end or the valve train that let go.

 

[Woodys_Cuda]

Now would be a good time to ask... How many of you will admit that you bolted a bunch of easy to do performance stuff on a high milage engine ( over 70K ) , only to have the bottom end come apart in less than 20K more miles ?

That could be more embarrassing than a slow timeslip.

 

[1968FormulaS340]

Don't expect much from just an intake and carb swap in a stock 318.

You WILL get something out of it but it will be far from life changing. It will feel like the same thing but as my grandpa would say "A little more poop".

Thats about it.

I wouldn't run a Holley 650 and no way would I run a Holley 650DP, even if you plan a build up in the future.

(Get the carb you need for your future build when you know for sure what you are building)

Both are over kill and the DP would simply suck *** on there.


If you just NEED to do it I would look used for sure. Any money you spend on this 318 comes off the top of your "Real" build.

If it were me..... I would just live with it and use my cash on parts for my 340 build.


Just a note... I don't know what you ran but lets say it was a 17 flat..... If you got a full second from the intake and carb swap (you won't) would a 16 flat really make you happy? If not don't waste the cash.

 

[63dartman]

If your not going to pull the engine and want to get serious about going to the track.....I would just live with it and put parts and funds away. Your heading down a road I've been. You can try to "wake up the 318" or just save your money for the "real" deal.

 

[rmchrgr]

Just a note... I don't know what you ran but lets say it was a 17 flat..... If you got a full second from the intake and carb swap (you won't) would a 16 flat really make you happy? If not don't waste the cash.

Probably not... good point! Guess I just had a little wounded pride, mind starts racing, gotta fix it NOW. Thanks for bringing me back down to earth. But hey, that's the beauty of this place, I get to bounce my emotionally charged up ideas off other members which clearly helps to keep me in check. BTW, car runs pretty good, cruises pretty easily. Gets up and goes from a 40-50mph roll but not going to beating anyone light to light anytime soon.

Like Dartman says, I'll probably just save my green for the real deal.
I don't have all the stuff laying around anyway. I do actually have some parts to make a 318 run pretty good, but not the manifold or a small enough carb. I'll end up needing throttle cables and brackets too and on and on.

It's funny how this all works. I start thinking I need a a manifold and carb, which turns into rear gears which turns into bigger tires which... you get the point.

 

[furz4]

I agree with the others if you need maximum power go to a 360 or 340. It all depends on what you want, mine runs mid 15's with a basicly stock 318 except for 340 cam and springs old streetmaster intake and 600 holley, good dual exhaust and some tuning. Also has transgo TF-2 which helps shave a couple of tenths off. I am still running the original gearing in the 7 1/4 2.76 and can get 20 mpg on the highway no problem. I am in the process of building an 8 3/4 for it and will probably run 3.23 or 3.55 gears and expect I'll just get into the 14's with that as my build is very mild. Even a 340 will be a dog with 2.76 gearing. If you motor is in good shape, doesent use alot of oil and compresion is good and oil pressure is good, bolt ons will work just fine. You cant expect too much with a tired motor no matter what you start with. If I had it to do over again I would have done the rear end first. I saw a test once where a stock 318 2bbl dart with 4.56 gearing ran 14.88. You will need the rear end upgrade if you plan on doing anything more then just crusing.

 

[AdamR]

I would do a small cam at the same time as the intake swap, Why pull the top of the motor apart twice ? The stock cam is aroun .410" lift so a intake/carb swap wont make a huge difference.

For a cam I would look for something like a comp cams XE262. I believe crackedback has a kit for sale right now.

Intake/carb wide, The stock iron and thermoquads work well but they arent what I would call cheap upgrades anymore. I paid around $200 for a 71 intake and 72 340 carb and the carb still needs to be rebuilt.

I think the LD4B or a Performer RPM would work well. I would run a carb around 600-650cfms.

 

[Badart]

I have a factory 4bbl intake I will sell you for super cheap. It's from a smog motor.

 

[Johnny Dart]

I wanna tell you I built a hot little 318 with a stock original motor,in my 70 Dart.It had about 70,000 miles on it.

All I did was add a Edelbrock performer with a Edelbrock 600,wich in my opinion is the perfect intake carb set-up for the 318. Also with a Edelbrock carb,all factory linkages/fuel lines bolt right up.

Electronic ignition.

Dual exhaust,Flowmaster 40's, H-pipe.
The kicker was the Hi-Po 340 manifolds !!

Never got a 1/4 mile time, but I tell you this car was no joke with this set-up.
I could roast the tires with this car. Was really fun to drive.

So yes you can wake up a stock 318 with the right bolt ons.

 

[CHEATHAM]

with a carb intake headers and electronic ignition you should be able to out run anything equivlent to your set up. a cam would be a plus but do the simple bolt ons and you'll be glad you did, some will tell you not to waste your time on this 318 but its yours so make it fun to drive. you wont gain much till you lose the point distributer and replace it with a elctronic.

 

[rmchrgr]

If I had it to do over again I would have done the rear end first. I saw a test once where a stock 318 2bbl dart with 4.56 gearing ran 14.88. You will need the rear end upgrade if you plan on doing anything more then just crusing.

Hmmmm.... I have a lovely aluminum center section with a 4.10 gear in it. That'd prolly work, huh? Might actually be under geared with that ratio. That's the gear that will ultimately be going in to the car too. I need to complete the rest of the rear end before it goes in though - axles, offset spring hangers and brakes. Cal Tracs are planned for as well. I often think about completing chassis stuff before the engine, good call furz4.

Funny to think about - a Dart with a stock 318 2bbl running Cal Tracs. Sounds like some bizarre stock eliminator car.

 

[Woodys_Cuda]

Funny to think about - a Dart with a stock 318 2bbl running Cal Tracs. Sounds like some bizarre stock eliminator car.

I have a friend running these traction bars with a stock 360 2 barrel in a 71 Cuda http://store.summitracing.com/partd...925130+4294839061+4294881589+115&autoview=sku

I haven't said anything about them, yet. :-D

One quick comment though. The intake/carb swap won't keep you happy for long. If you can stay away from the track for awhile, your money is better spent on real performance parts.

 

[metallidart]

I'm going to be doing the same to my Dart until my 408 is done, I just wanna drive it. I have a 318 lying here, bearings look good, bores look good. I also have a crane .460.450 224/232 cam, new valvesprings, timing set, and 1850 Holley 600, manifolds, and 2 Flowmaster 50 series mufflers. All I have to do is find a LD4B, get gaskets and an oil pump, and I'm going to see what it will do. Oh, and I'm gonna port the 318 heads a little. I won't barely have any money in it, everything but the valvesprings and timing set are used. The trans is a 904 that I just rebuilt with a converter that stalled at 3200 with my 360, I'm guessing it will be lower now but it has to be better than stock. The rear will be 3.55 sure-grip 8 3/4, SS springs, etc. Any guesses as to what it will run? My LD340/same cam/home ported stock valved J heads on a stock bottom end 360 ran 13.60's for the last 10 years, and I barely ever ran it easy. Still ran good when I sold it, and that was with a peg leg 3.23 center.

 

[flyfish]

I think the LD4B was an ancient predecessor to the performer. I've read lots of good things about it and it's sized correctly for the 318. The Holley 80454 is a 600 cfm vac. secondary/electric choke carb.

My plans for down the road a way different - I have a 340 block that will get a a 4" crank, so it's like apples to oranges. This is 'just for now' to have a littler bit more fun and not be so wimpy when they flash my time up on the score board!

If you’re going to go stroker down the road, I would just save your money…you’re going to need it! :-D

 

[flyfish]

I wouldn't run a Holley 650 and no way would I run a Holley 650DP, even if you plan a build up in the future.

(Get the carb you need for your future build when you know for sure what you are building)

Both are over kill and the DP would simply suck *** on there.

My old 318 responded well to a 650 dp, if I recall correctly it picked up about 3 tenths. The only reason I would recommend the dp is its easy to upgrade when you start making more power (with a proform main body swap you can have a 750 dp). I agree, if you have future plans for a bigger motor, just wait and save your money.

 

[ramenth]

I'm hearing a lot about intakes, exhaust, carbs, cams, etc. Man, I was waiting to hear the obvious. Wake up a 318? 360 heads. Reason why Mopar used the 360 upper end on all those 318 cop motors back in the day. The more air in, the more air out, the more horse being made... Takes half a day to bolt 'em on with the engine in the car...fire it off, instant gratification.

 

[C130 Chief]

The carb and intake you have in mind will work great on a mild 318. Since you will have the intake off, I would replace the cam. My reasoning would be that the original timing chain and cam sprocket are probably still in there and WILL fail at some point regardless of the carb. The XE262 or a stock 340 cam will work well.

Sure, the cast iron exhaust manifolds will hold you back a little, and if you are still running single exhaust, FIX THAT FIRST before the carb.