Why? I can turn my 416 back into a 340 with little effort!
Question about the price of 340s
- Thread starter Relax360
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The other reason they did away with the 340/426 was for insurance reasons. The 71 340 was rated at 275 HP. 72 and 73 at 240 HP. Also HP rating on all cars went to rear wheel. Again because Insurance companies flexed their muscles! And now days you can buy a Demon rated at 857HP! Kinda makes the 426 Hemi look like a auxiliary kicker! Eh?
340dartley
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340s just seem a little more special due to their low production numbers. I don't dislike any classic mopar engines. Personally I have a 340 in my bracket car which is an original 69 swinger 340 car. I have a core 340 in the garage. 2 318s 1 440 2 383s and 1 360 core. I don't discriminate.
ir3333
Well-Known Member
I am pretty sure that was for smog reasons not performance.
i thought the 360's bigger displacement would allow a little more pollution so they could keep a performance sm blk.
Simple, supply and demand.
Sorry, wrong. They did not rate HP at the tires. No American automaker did this then or now. They started rating HP with a full exhaust system, a closed air cleaner assembly, a water pump and fan. This was done to get a more realistic "guess" to the actual HP the engine made. Again, NO rear wheel dyno ratings were used.
i am a member of the "340 cult." i have two full motors and a third redone painted block. i street raced "the 340" when it was "first made" (1968). at the time, NOTHING from Ford, Pontiac, Olds, or Buick could beat it in a quarter mile taking all these cars right off the car hauler. only a "factory fresh" 68 corvette 427/435 tri-power (or L88) would send ANY mopar 340 A-body car back to the staging lanes. the reason was simple physics: a stock 340 was "a factory race motor" and could be safely wound to 6500 and the power/torque it produced was substantial in the light A-body chrysler cars. that motor in the A-body cars were a very balanced package. the cars launched well with minimum wheel spin allowing at least a car's length from other muscle cars of the day. then because the motor would go to 6500, this car length advantage could be sustained longer before the shifts happened in a 4 speed car. the same advantage could be gained in a torque flight car if you installed a "shift kit" upping the RPM shift points for the auto trans.
now, if you are going to race or abuse your car, DON'T install a 340 - they are too valuable these days (especially to guys who want to restore 68/69 A-body cars to "stock"). if you are going to run the risk of putting a connecting rod through the side of your toy's motor at some point, build a 318 or a 360. nobody cares about turning those blocks into boat anchors because there are "literally" millions of those engines around.
i wanted to send up just a "small" red flag here - and of course, represent my fellow "340 cultists" fairly.
now, if you are going to race or abuse your car, DON'T install a 340 - they are too valuable these days (especially to guys who want to restore 68/69 A-body cars to "stock"). if you are going to run the risk of putting a connecting rod through the side of your toy's motor at some point, build a 318 or a 360. nobody cares about turning those blocks into boat anchors because there are "literally" millions of those engines around.
i wanted to send up just a "small" red flag here - and of course, represent my fellow "340 cultists" fairly.
dibbons
Well-Known Member
Jim Harvard just said: "the motor would go to 6500". I wonder if he meant with the single/damper factory valve springs or with aftermarket valve springs?
the 340 motor in my original 68 formula S had an edlebroc alluminum high rise manifold, hooker fenderwell headers, a holley 750 dp carb and a "viscus drive" clutch fan. other than that, it was stock - all the internals were OEM. my "Sun Super" Tach had its red needle set on 6k but in many a street race, the needle was still moving when i would power shift. except for the 69 Z/28 302, there were very few engines other than the 340 that would go to 6k on a regular basis without a serious risk of a BIG BANG coming from under the hood.
just for the record, here's a list of old "stock muscle car" motors that exceeding any RPM over 5500 was playing "Russian roulette:" chevy 396, 427; ford 390, 428, 429 (not the 429 "hemi" motor); pontiac 389, 400, 428, 455; olds big block; buick 455. you could take 440 and 426 hemi mopars to 6k but it was a "scary experience."
dibbons
Well-Known Member
Regarding your viscous drive fan, I just installed the Mopar version (5 blade) and in traffic jams my coolant temperature has climbed to the half way mark and then a little beyond and I never have heard the fan kick-in. I stored it properly "this side up" and I never observed any fluid leaking. Very disappointed.
When 360 came out in 71 and if it came with all the 71 340 goods. It would of been top banana and 340 would be more like how Chev view the 327.
Too bad Chrysler just didn't add the 3.58 stroke to the 340 block in 71 and come up with a 367.
Too bad Chrysler just didn't add the 3.58 stroke to the 340 block in 71 and come up with a 367.
ir3333
Well-Known Member
that would have been costly with the 3.58 stroke large journal crank.They would have needed new pistons as well and they wouldn't balance with the cast crank.360's had sm valve heads too.They wouldn't have re-tooled in lieu of the dropping performance, emissions and oil industry problems.1970 was the last performance year for most.
I love the 340 in my 71 Demon. Motor was rebuilt before I bought the car. It seems fairly stock. In saying that the 71 340's were factory rated at 275hp & yes I know that was underrated. Mines got 340hp (that's at the flywheel not rwhp). Goes fast enough for me I'm 50 years old so big hp's not the end of the world. In saying that when I jump on it, it certainly throws you back in your seat & has plenty of pull that's for sure.
Do you really think .040 of an inch in a 4.000 bore makes any difference?
Relax360
Well-Known Member
Well I think the topic has been covered they are harder to find and people want more money
in the late 1960's, there were lots of "factory" and "after market" parts you could buy to make your mopar run faster. mopar sold "viscus drive" radiator fans through the parts counter Direct Connection program. mopar claimed that taking off your "solid bolted" radiator fan and replacing it with a "clutch fan" or "viscus drive" fan was good for a 5 hp increase. back then, "bolt on" horse power was the rage so anything you could "take off" or "bolt on" that would increase power was popular. that's why a lot of old muscle cars do not have power steering or air conditioning (and "young kids" couldn't afford these options) - and of course, air pollution air pumps usually got taken off in the drive way as soon as a young gear head got his ride home from the dealer. it does not surprise me that the viscus fan is not cooling your car in traffic. these fans do not turn as fast as solid fans and thus do not produce as much air. they are designed to provide air flow while reducing the "torque load" on the motor. they work better for "racing" rather than "sitting in traffic." for maximum cooling, it's hard to beat "factory design" which is: a fixed bolted fan, a fan shroud properly spaced between fan blade and radiator, correct size and in good condition radiator. remember, car companies ALWAYS spent millions of dollars finding the right "compromised" set of components and specs in order to make the car the best performing for "normal" driving. when you decide "to go racing", you are going to affect the "drive ability" of the subject car.
pishta
I know I'm right....
Fords 351C was made for only 4 years but you could get them in Torinos, Rancheros, Cougars and 'stangs....They wind to the moon, make more power and are not half the price of a 340. Mopar tax!
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Well since most of us, or at least a lot of us, are running about 1.1 or better hp/cid, .040 is about 7 hp at peak.This is about a half, or almost a half, a cam-size.
But the boost in ftlbs at low rpm is a welcome thing with a stick-car.
But mostly, I have a 4.04 x 3.58 cuz I can sorta call it a stroked 340 which elicits oohs and aahs at car shows whereas 367, invariably brings out the ignoramuses who parrot the "you shoulda put a 340 in there" mantra.
I coulda put a 340 in there, if I wanted to be slower with the same parts I chose.
In fact I had 4 of them sitting right beside the 360 on decision day.
I mean why settle for a 340 in this day, when you could have over 20 cubes more for the same money spent? Stick cars especially like the extra oomph off the line, Cuz we don't have the extra TM in the TC, which can be very significant. So for us, the 22 additional cubes, and the one size smaller cam, adds up to a stronger punch off the line a much stronger midrange, about the same top-end power, and more mpgs with perhaps one size smaller rear gear.
Here's a comparison
First a 345 cuber(4.07x3.315), with a 268/276/114 cam in at 110
Static compression ratio of 10.3:1.
Effective stroke is 2.57 inches.
Your dynamic compression ratio is 8.21:1 .
Your dynamic cranking pressure is 165.35 PSI.
V/P (Volume to Pressure Index) is 133...............................................133
Second, a 367 (4.04 x 3.58)with a 262/270/110 in at 106
Static compression ratio of 9.75:1.
Effective stroke is 2.95 inches.
Your dynamic compression ratio is 8.21:1 .
Your dynamic cranking pressure is 165.35 PSI.
V/P (Volume to Pressure Index) is 150...............................................150
Both are set up to run the same Dcr and cylinder pressure, at about the max for pump gas and closed chamber iron heads.
Notice the VPs, 150/133 = about plus 12.8% for the 360. This will allow the 360 to run 3.23x2.66 (M/T) for a starter gear of 8.59,times say 200ftlbs take off=1718# at launch.
against the 340 with 3.55x2.45=8.70 x an instantaneous say 1.7 in the TC =14.8 times (say at 2800TC and) 177 ftlbs=2624# instantaneous, falling to 1562x1.1(lol)=1718# just a short ways out. So this makes them about equal in the lower rpms, in first gear.
Then at peak torque, the 360 is gonna make maybe 420 to the 340s say also 420. But the 360 is gonna make it at least 200rpm sooner.
So the 360 at 49mph and 3750 will be putting down 2468 road ftlbs, in 2nd gear.
and the 340 at 49 also in 2nd gear will be spinning just 3300 rpm(5% slip) , no where near its 3900 torque peak. But let's say it's making 95%, or 380ftlbs; then 380 x1.45x3.55 x1.1 in the TC=2152
But let's wind 'em up to the power peaks. I chose 5200 for the 340 with the 268, and 5000 for the 360 with the 262. And I chose the same power level for both,say 360hp for kicks.
So lets bias this for the 340 at the top of second gear. Ok so 360x5250/5000=378 ftlbs. and 378 x3.55x1.45x1.1TC =2140# @74 mph.
So lets compare this to the 360 at 74 mph
This will be 5671rpm, so we will be on the downside of the curve quite a long ways in second gear. Lets guess the 360 is down at 335hp so about 310 ftlbs. Ok' 310 x 3.23x1.91 = 1913# so she's down 11%.
So lets take her up to peak power in the 360 in 3rd gear; this is 360hp/343ftlbs, and 343 x 3.23 x 1.40 =1550# at 89mph.
Now the 340 at 89mph, is doing 5976 rpm and is 776 rpm past its prime, so I'll guess 300hp or 264 ftlbs. So 264 x3.55x1.45 x1.1=1492, so it's down 4%
Now let's take them both to 100 mph.
So the 340 car will have to be in third, and that gets her 4630 rpm, about569 rpm below peak power, so I'll guess 380#. And 380 x 3.55x1x1.1= 1484 ftlbs.
Next the 360;which is still in 3rd gear@ 5618rpm, or 618 past it's power peak, so I'll guess 320hp, or 343 ftlbs. And 343x3.23x1.4=1548 ftlbs and so it's up 4.3%.
So I'm gonna guess they'll run neck and neck to the stripe.
But the 360 will cruise 65=2608 compared to the 340 at 2867(zero slip), or plus 259rpm. So that gives the nod to the 360 for fuel-economy.
Now let's talk about overlap and power extraction. the 340 cam has 44* overlap compared to the 360 cam at 46* so that's a wash,
And the 340 has 104* extraction as compared to the 360 at 111*, so that 7*/6.7% gives the nod to the 360 for fuel economy. Again.
If I were to guess; the 360 will get at least 4 mpgs better in point to point steady-state cruising at the same speeds, mostly cuz of the lower cruise rpm
And lest anyone missed it, the 340 runs 10.3Scr to the 360s 9.75 for the same Dcr/pressure. At zero-deck the 340 needs about a 62cc chamber, compared to the 360 needing a 72cc chamber. Both for a .039 gasket and 5cc eyebrows.
so to recap; the 360 will need less cam and less gear to trap with the 340 car, but cruise 259 rpm lower, and extract more energy out of every gallon of gas consumed, mostly while cruising.
And the part I like is when I stomp it at LOW-rpm, I don-need-no-steenking hi-stall; I got VP.
All pure speculation, your results may vary.
But yeah, as to the price of them, up here they still are not worth much,which is why I've been hanging onto the 4 or 5 I got. But I've had them now since the 70's so............. maybe it's time ....................
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non numbers matching car? save your cabbage bro. punch out a pre 72 LA318 and find a forged crank. just don't overbore past .04 of a 340. you cant see cylinder distortion or compression blow by past the rings cause of out of round cylinders. the smaller main journal non 360 crank will keep bearing speed lower. the shorter stroke crank will make rpm quicker and be more fun to drive on the street. best to keep power below 500 hp to keep from eventually splitting the cylinder walls. IF YOUR AFTER HIGH HORSEPOWER, find an old X block or better yet find an R block and change the lifter angle to 48 degrees.
those 2 type blocks are worth throwing cabbage at to acquire, within reason.
those 2 type blocks are worth throwing cabbage at to acquire, within reason.
friends don't let friends drive fords.
interesting argument and well argued.
I don't quite get this?? Why was it a "scary experience"/ "Russian roulette"??
The first engine I took apart and put back together again.....that ran....was the 389 in my brothers 65 GTO, I was a Junior in High school, in Auto shop. Simple ring and bearing job, first valve job, did a cam upgrade, haven't the slightest recollection of what the cam was I put in, bought it thru the local NAPA store, they gave the school a discount, it came with 7000 rpm hydraulic lifters. Once I got my license so I could legally drive, I tested that specification regularly. It even survived an episode of "watch this.........." where I came close to 8000rpm; it got a funny sound, I looked in the rear view mirror for pieces on the ground.....nothing, I goosed the throttle, the tack still moved, no funny sounds; I kept driving. I was aware of Pontiac's reputation for blowing up, now at this point, I kinda wonder if it was more of an Urban legend like so many things now.
340's cost what they do, because people will pay, pure and simple. For a restoration it almost makes sense, almost. Since it's not likely to be the original engine to the car, it begs the question, WHY?? The original engine met it's demise in some form of street combat "back in the day", or "watch this........" as the owner showed off about how far he could wind his 340.
Capitalism at it's ugly best.
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