stu’s68furyiiirat
Member
I have a cast iron 2bbl intake with new 2bbl stock carb would it be worth porting the heads for bigger valves and 4 bbl intake and 650 carb will I gain anything or not
68 fury iii 318 Carb
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57fury440
Well-Known Member
I put an Edelbrock 1406 carb on a 4-barrel manifold along with a 340 cam and lifters on a 318 in one of my son's cars. We also added a nice dual exhaust system. It made a noticeable difference. If you just want some more power, it is not a bad way to go and will not break the bank. We also put 3:55 gears in it and everything together made a big difference.
To answer your specific question, and not bring in camshafts and strokers and 360s and aftermarket aluminum 340 heads and dual exhaust and superchargers and nitrous oxide and.....well, the answer is simply "no". Let's be realistic here. The two barrel on that engine is quite sufficient to supply all the flow that engine can use. Might you gain a very few HP? Maybe, but what about drivability? And I'll mention that you don't "port the heads for bigger valves", but I know what you mean. Those two things are related, but are not the same. Heads can be ported. Heads can sorta have bigger valves installed, but not by much (it's a lot of work and no self-respecting machine shop would do that on a 318). Or both can be done. But on a 318--as you said--it's going to be "or not".
For my 440, which is actually 448, I selected the Street Demon 625 on the Eddy Performer intake. At 5200 rpm, that 448 street engine can only use 573 of that 625 cfm available, and it runs like a sumbitch to 5200 in a 4400 lb car. On a 318 at 5200, it's 406 cfm max. At 6000, it's 469. Are you revving to 6000? Simply, you don't need a 650 and you don't need the headaches that come with this mod. And you're not going anywhere with an OEM single exhaust, but you didn't mention that. But if you want to do it to just do it for bling, have at it. But be realistic about any power gains by doing exactly what you are considering doing.
Here's a cfm calculator: CFM Calculator
I've built a lot of smallblock Mopars, most for street racing and track use. Lots of 340s, one 340 T/A and I did the 360 "Hoover Mover" engine that becomes 380 inches when it's all done. Hoover's Mover ( Feb-1976 ) My first engine ever was a 318 in my 68 Dart. I put a Holley 500 two barrel and headers/dual exhaust on it. It was more fun than effective. Maybe a wee bit more power, or maybe not. After all....it was a 318 and I was 17. I should have installed a supercharger and nitrous but I didn't know what those things were back in 1974.
Now that Trace has opened the door . . .
You CAN do everything to a mere 318 that you can do to a 340. Many of these things are detailed in the Mopar Connection Engine Manual for LA motors. You can even swap sides with the pistons, if desired. All it takes is $$$$ to cut the upper edges of the cyl bores to clear bigger valves and such, plus the other things needed.
But bigger valves is not a good answer, as it takes more port flow to need them. LA motors are, like other Chrysler motors, "package motors" where the various pieces are selected to meet a particular end result. Not that other OEMs don't do similar, just that it seems that Chrysler perfected that orientation, in most cases.
As to cams, it is very easy to over-cam an approx 300 inch motor than a 400 inch motor. IF you might desire . . . you can take the "Chevy Killer" 340 and downsize the cam, valve sizes, and such to achieve the same thing in a 318, but with a little bit less power due to the smaller size. And, it might well be similar to what you currently have, in many respects. Just need the intake, small 4bbl, 340-style exhaust manifolds, and good dual exhaust system to add. Search the salvage yards for a 318 4bbl cast iron intake for a TQuad, for example. IF you find that, then get the top side of the motor, for good measure, with the exhaust manifolds, too.
The OTHER thing is that you might need some internal upgrades to the A-904 trans, if that is what the car has. An old HOT ROD magazine article claimed that after about 20 WOT passes on the drag strip, the trans would need some internal attention anyway, for which B&M had a kit to fix, back then.
NOT that the 318 can't be improved, just that for a 4000lb car with a 2.93 rear axle ratio, it'll never be a 318 Duster as to straight-line performance, for example. For your application, you need TORQUE to get the car moving and then enough engine air flow to keep the party going to about 5000rpm, then upshift and go again.
Forget about horsepower numbers. The max power only happens as MAX RPM. Torque is not sexy to talk about, but that's what moves the car from idle. Play with the base ignition timing and advance curve to help off-idle response. Then add about two more turns of preload into the kickdown rod adjustment, which can raise normal shift points a few mph, for better feel. Little things can make enough difference that you'll not miss not having a 4bbl and such. As these things happen at "below 2500rpm", NO engine dyno numbers exist, just the "seat of the pants" feel.
Keep the tire tread width to 7" or narrower. Those wide tires which people tend to like just take more power to turn, power which you might not have. Harder to spin, too! Better to have a car that looks normal and MOVES than one which looks powerful and is not, by observation.
IF your 318 Fury does not have a front anti-sway bar, GET ONE from the salvage yard from a 383 car. Might need the lower control arms, too?
Forget about "dyno numbers", nobody really knows what they feel like anyway, usually. Make the car feel better driving it, LEARN to drive it, too. See how little throttle it takes to move it from stopped rather than trying to lay rubber with a WOT stomp, for example. Perfect a 3-2 part-throttle manual downshift for freeway on-ramp activities. Works pretty slick when you get it. right!
Sure, when I was in junior high, I'd take a JCWhitney catalog and make a 300 horsepower V-8 into a 400+ horsepower engine with several add-on parts, 20 horsepower at a time. Not knowing how a too-big carburetor and over-sized camshaft would act in the real world, but "the numbers" were good. Or trying to squeeze all of that power through a 2.0" dual exhaust system!
My late machine shop operative would always chuckle at guys who'd come in to see about getting an engine built. They didn't really know what they needed, but they always gravitated to the parts listed "at the bottom of the page" (where the bigger numbers were). When they should have been shopping up toward the middle of the page or higher. After they had talked a bit and had gotten more knowledge of what it took to "get there", he built them an engine "that worked". And they were happy. Because . . . he started out as a hot rodder from his teens, with accumulated knowledge of what would work on the drag strip and also on the street. He worked until he couldn't. We laid him to rest about 3 years ago. He was in his later 80s. A long life well-lived.
Sorry for the length. Take care,
CBODY67
You CAN do everything to a mere 318 that you can do to a 340. Many of these things are detailed in the Mopar Connection Engine Manual for LA motors. You can even swap sides with the pistons, if desired. All it takes is $$$$ to cut the upper edges of the cyl bores to clear bigger valves and such, plus the other things needed.
But bigger valves is not a good answer, as it takes more port flow to need them. LA motors are, like other Chrysler motors, "package motors" where the various pieces are selected to meet a particular end result. Not that other OEMs don't do similar, just that it seems that Chrysler perfected that orientation, in most cases.
As to cams, it is very easy to over-cam an approx 300 inch motor than a 400 inch motor. IF you might desire . . . you can take the "Chevy Killer" 340 and downsize the cam, valve sizes, and such to achieve the same thing in a 318, but with a little bit less power due to the smaller size. And, it might well be similar to what you currently have, in many respects. Just need the intake, small 4bbl, 340-style exhaust manifolds, and good dual exhaust system to add. Search the salvage yards for a 318 4bbl cast iron intake for a TQuad, for example. IF you find that, then get the top side of the motor, for good measure, with the exhaust manifolds, too.
The OTHER thing is that you might need some internal upgrades to the A-904 trans, if that is what the car has. An old HOT ROD magazine article claimed that after about 20 WOT passes on the drag strip, the trans would need some internal attention anyway, for which B&M had a kit to fix, back then.
NOT that the 318 can't be improved, just that for a 4000lb car with a 2.93 rear axle ratio, it'll never be a 318 Duster as to straight-line performance, for example. For your application, you need TORQUE to get the car moving and then enough engine air flow to keep the party going to about 5000rpm, then upshift and go again.
Forget about horsepower numbers. The max power only happens as MAX RPM. Torque is not sexy to talk about, but that's what moves the car from idle. Play with the base ignition timing and advance curve to help off-idle response. Then add about two more turns of preload into the kickdown rod adjustment, which can raise normal shift points a few mph, for better feel. Little things can make enough difference that you'll not miss not having a 4bbl and such. As these things happen at "below 2500rpm", NO engine dyno numbers exist, just the "seat of the pants" feel.
Keep the tire tread width to 7" or narrower. Those wide tires which people tend to like just take more power to turn, power which you might not have. Harder to spin, too! Better to have a car that looks normal and MOVES than one which looks powerful and is not, by observation.
IF your 318 Fury does not have a front anti-sway bar, GET ONE from the salvage yard from a 383 car. Might need the lower control arms, too?
Forget about "dyno numbers", nobody really knows what they feel like anyway, usually. Make the car feel better driving it, LEARN to drive it, too. See how little throttle it takes to move it from stopped rather than trying to lay rubber with a WOT stomp, for example. Perfect a 3-2 part-throttle manual downshift for freeway on-ramp activities. Works pretty slick when you get it. right!
Sure, when I was in junior high, I'd take a JCWhitney catalog and make a 300 horsepower V-8 into a 400+ horsepower engine with several add-on parts, 20 horsepower at a time. Not knowing how a too-big carburetor and over-sized camshaft would act in the real world, but "the numbers" were good. Or trying to squeeze all of that power through a 2.0" dual exhaust system!
My late machine shop operative would always chuckle at guys who'd come in to see about getting an engine built. They didn't really know what they needed, but they always gravitated to the parts listed "at the bottom of the page" (where the bigger numbers were). When they should have been shopping up toward the middle of the page or higher. After they had talked a bit and had gotten more knowledge of what it took to "get there", he built them an engine "that worked". And they were happy. Because . . . he started out as a hot rodder from his teens, with accumulated knowledge of what would work on the drag strip and also on the street. He worked until he couldn't. We laid him to rest about 3 years ago. He was in his later 80s. A long life well-lived.
Sorry for the length. Take care,
CBODY67
But but but but but....that's not what he asked.
My intent was to close the door to the thousands of suggestions and erroneous advice that guys on all motor vehicle forums always leap to provide to an OP, while ignoring what that OP originally asked about.
Did you ever hear the story about the admiral who wanted a lifesaver? They brought him life vests, rings, rescue boats, frogmen, the Coast Guard. All he wanted was a piece of candy.
My apologies if I "over-delivered" by possibly answering "future questions" in the process. Just trying to consider "reality issues" of trying to make a 318 more powerful, without forced induction and especially without NOS.
A point of reference from the late 1950s Poly318s, the "power pak" option of 4bbl and dual exhausts (as small as they might have been back then) was about 25 advertised horsepower back then. Probably a 450 cfm 4bbl carb with 2.0" exhaust pipes with normal mufflers.
Regards,
CBODY67
A point of reference from the late 1950s Poly318s, the "power pak" option of 4bbl and dual exhausts (as small as they might have been back then) was about 25 advertised horsepower back then. Probably a 450 cfm 4bbl carb with 2.0" exhaust pipes with normal mufflers.
Regards,
CBODY67
Last edited:
stu’s68furyiiirat
Member
I have the edlebrock 650cfm carb and intake I just wanted to swap it I already have dual exhaust with 40 series on it hei dizzy does anyone have a good link for cam and lifters upgrade
Triple Pickle
Senior Member
I foresee yet another kickdown linkage thread in the making.
Other than that, you want to go with a small “RV” camshaft. As has been said here already, this stuff that you’re doing will be felt at the top of the rpm range, if at all. When you set up for volume and you really need velocity, you hurt the bottom end. That’s where you need it in a heavy high geared car.
Other than that, you want to go with a small “RV” camshaft. As has been said here already, this stuff that you’re doing will be felt at the top of the rpm range, if at all. When you set up for volume and you really need velocity, you hurt the bottom end. That’s where you need it in a heavy high geared car.
A 4 barrel and intake, dual exhaust, and a new distributor curve will make a lot of difference to your 318.
To answer the first question, maybe. But all the work and money this will cost, and will the end result be worth it? NOPE
begger valves will need a bigger camshaft and more compression. So you are talking a whole new engine.
get a 440 and then you will have something.
begger valves will need a bigger camshaft and more compression. So you are talking a whole new engine.
get a 440 and then you will have something.
57fury440
Well-Known Member
Leave the heads alone and do what toolmanmike listed. You will see and feel a difference. A mild cam will help too. Going to a big block would give you more power and torque but would not be cheap to do. Some simple modifications will give you more performance from the 318 for not a lot of money.
As @Trace 300 Hurst says, to answer your specific question, the answer is basically "no".
Maybe a small 4bbl carb might give you a little more "snap", but really, it's still gonna be a dog. Bigger valves? No. The 318 heads aren't going to get any better.
The question from us is "what do you want from this car?"
The 318 is a great motor. It rivals the /6 for longevity and reliability. If you just want to go to the "cars and coffee" at the local Dairy Queen on Saturday, it's perfect.
Want to go fast? That's a whole 'nother thread... Once you go down the path of making modifications, it steamrolls very quickly. It can get expensive and chances are you'll need to do more wrenching after making the changes to get it right.
I've seen so many guys do all the mods to make their car fast. Usually, those cars end up sitting in the garage for one reason or another and it's often because the mods took the fun out of the car.
My advice is to leave it alone, work on making it run right and look good. You'll have more fun and be much happier in the long run.
stu’s68furyiiirat
Member
I agree I don’t need to spend alot of money
stu’s68furyiiirat
Member
It runs good on the 2bbl trans it awful I’m trying to straighten it out but I have the carb and 4 bbl if I ever decide to pull motor
stu’s68furyiiirat
Member
I just want a reliable cruiser
Bingo!! There's everything "right" about a reliable cruiser.
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