340 camshaft recommendations for stock converter

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Hello,

I will be rebuilding a 340 for my duster soon with mostly stock components and wanted to get some recommendations for a camshaft for it. I just got the engine yesterday and I can tell it has a forged steel crank, J heads and the factory cast iron intake. I will be using this car for some of my daily driving duties so I don't want to fight with it in traffic. I just want a solid performer that makes the best use of what I have. I will put a set of headers on it and likely a 650-700 cfm carb. I may upgrade the intake in the future but want to see how it performs with the factory piece first. Rear gear ratio will likely be 3.23 or 3.55 and the trans will be a stock 727.

I was looking at something like these from Howards Cams. I've used one of their rattler cams in a chevrolet build a few years ago and I was very impressed with the performance. It wasn't a cam designed for sound, it flat out made power and proved itself on the chassis dyno.

Hydraulic Flat Tappet Camshaft & Lifter Kit; 1964 - 2003 Chrysler 273, 340, 360 1800 to 5600 Howards Cams CL711651-10 | Howards Cams
Hydraulic Flat Tappet Camshaft & Lifter Kit; 1964 - 2003 Chrysler 273, 340, 360 1800 to 5800 Howards Cams CL711451-08 | Howards Cams
Hydraulic Flat Tappet Street Force 3 Camshaft & Lifter Kit; 1964 - 2003 Chrysler 273, 340, 360 1600 to 5800 Howards Cams CL712121-12 | Howards Cams
Hydraulic Flat Tappet Rattler Camshaft & Lifter Kit; 1964 - 2003 Chrysler 273, 340, 360 2000 to 5800 Howards Cams CL718001-09 | Howards Cams
 
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After running the numbers on the engine, I have a 72 340, made on September 30, 1971. So it would have lower compression and smaller valve heads, correct? R denoting regular fuel?

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You lost me at the point of you want to put headers on it .....

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No headers here . . .

☆☆☆☆☆
 
i'd go with the CL712121-12 or CL718001-09

the -12 is hotter than a stock 340 4spd cam and the -09 is even more so, but the duration numbers are strikingly similar. i'd shy away from running .500+ lift on the street in a daily because you're going to need gears and a converter.

my pick would be the -12 if you're keeping the 3.23's and with the headers you'll probably pick up a bit of midrange torque. spot on carb size for street daily. that manifold will run pretty much neck and neck with an aftermarket with a mild combo (smaller, more reasonable cam, carb and decent compression). you *might* see some better low and midrange numbers and driveability with an aftermarket, but you'd be hard pressed to feel it in the seat of your pants.
 
That would be a lower compression 340 if it still has the stock internals. The factory intake is so good that unless you have an edelbrock rpm or an old Edelbrock LD340 handy, you’ll be ahead running it. Those are all good cams, but the one that will work best depends on how far you’re going to go from stock with it. Some will probably require machine work for the lift. junkyard hero pretty well nailed it on those, and everything else, too. Do you plan on going back with stock type pistons? I would plan on going back together with at least 9.2:1 compression. If it’s needing an overbore, it would be a good time to upgrade them. You said stock 727, are you planning on a factory high stall converter or an aftermarket option?
 
Garrett Ellison said:
That would be a lower compression 340 if it still has the stock internals. The factory intake is so good that unless you have an edelbrock rpm or an old Edelbrock LD340 handy, you’ll be ahead running it. Those are all good cams, but the one that will work best depends on how far you’re going to go from stock with it. Some will probably require machine work for the lift. junkyard hero pretty well nailed it on those, and everything else, too. Do you plan on going back with stock type pistons? I would plan on going back together with at least 9.2:1 compression. If it’s needing an overbore, it would be a good time to upgrade them. You said stock 727, are you planning on a factory high stall converter or an aftermarket option?
Click to expand...
Thank you for the feedback. I’d like to keep the factory high stall. Those flash about 23-2400 rpm, correct? I agree, I plan to up the compression when I go through it. I was thinking 9.5-10:1. I wish I had spare LD340! I have one on my Cuda. I’ve had 4 different intakes on it and it’s by far the best one!
 
You have the factory high stall? Nice!
For a hot street and everyday car I’d go with what I posted as the second cam & 3.55’s. Let’er rip!
 
junkyardhero said:
i'd go with the CL712121-12 or CL718001-09

the -12 is hotter than a stock 340 4spd cam and the -09 is even more so, but the duration numbers are strikingly similar. i'd shy away from running .500+ lift on the street in a daily because you're going to need gears and a converter.

my pick would be the -12 if you're keeping the 3.23's and with the headers you'll probably pick up a bit of midrange torque. spot on carb size for street daily. that manifold will run pretty much neck and neck with an aftermarket with a mild combo (smaller, more reasonable cam, carb and decent compression). you *might* see some better low and midrange numbers and driveability with an aftermarket, but you'd be hard pressed to feel it in the seat of your pants.
Click to expand...
Thanks for the feedback! I look forward to putting this one together!
 
rumblefish360 said:
You have the factory high stall? Nice!
For a hot street and everyday car I’d go with what I posted as the second cam & 3.55’s. Let’er rip!
Click to expand...
I’m almost certain that’s what it is. This was a combo that’s been together in storage since the late 70s. I just got the 727 book and looking at it the converters came with this sticker on them? I’m sure this is likely long gone from mine but if the converter measures 10.75” in diameter, that’s the way to physically verify, correct?

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I actually don’t know. I’ve been a Row my own boat kind of guy for decades and I’m only getting to automatic transmissions now.
So, since is the case, all converters are custom ordered and built since all of my camshafts and builds area but far beyond stock. Smallest cam is a hyd roller @224@050 intakes side for the wife’s ‘67 Cúda w/3.55’s and a 904 on 26X10 tires. Stall is a little tight @ 2500. Works well, excellent driver.
 
Around 220+ @ fifty is where you start really trading low end torque for higher end hp.
Trick is you want to extend the powerband higher end rpm (hp) with little effect down low.
It's a judgement call everyone's compromise is different, more under 220 is a safer bet, 220 and over really depends on the person. Obviously there more to it than the intake duration.

Take the Xe comp cam line the xe250h is similar to stock which leaves xe256h and xe262h under 220 and xe268h 224 being about 220 and xe275h anf xe286h above being more street strip type cams where higher stall and deeper gears are desired. So xe268h is a mid ground cam in the line up.
 
It's not a 340 but shows what xe262h size cam behaves like and can guesstimate from there


Here's an stock low cr 318 with 4bbl xe262h cam and headers mod 1&2 base is stock 2bbl with headers.

TORQUE SUPERFLOW 901 DYNO-TESTED AT WESTECH
RPMBASEMOD 1MOD 2
2,000292
2,500287
3,000287338336
3,500272335340
4,000248326330
4500218309319
5,000188285296
5,500250258

318 Long Block Bolt Ons - Tech Articles - Mopar Muscle Magazine
 
If it was me, I would run the stock intake and carb.
I also would run the original 340 cam if it is in good condition
with new lifters.
These cars would run to 6000 easily with stock springs and camshaft
and were good daily drivers that would run 13s in quarter if well driven
and tuned!
My son and I both run NHRA legal stockers that run Mid 10s @ 125
with stock intake and carb plus stock lift intake = Nothing wrong with intake
and carb.
 
I’ve said that about the TQ & the stock factory 4bbl. a lot. Everyone dumps it for an aluminum intake & a Holley.
I’ve said it before the FAST class came around in which they (the FAST class) proved it and honestly floored me on what they have done with it.

I think I mentioned it in RustyRatRods thread “Hot Rod Bliss” thread. You can get pretty far with a factory carb, intake & heads but it might not be for everyone. A lot of carving goes into it.
 
273 said:
It's not a 340 but shows what xe262h size cam behaves like and can guesstimate from there


Here's an stock low cr 318 with 4bbl xe262h cam and headers mod 1&2 base is stock 2bbl with headers.

TORQUE SUPERFLOW 901 DYNO-TESTED AT WESTECH
RPMBASEMOD 1MOD 2
2,000292
2,500287
3,000287338336
3,500272335340
4,000248326330
4500218309319
5,000188285296
5,500250258

318 Long Block Bolt Ons - Tech Articles - Mopar Muscle Magazine
Click to expand...
I'm assuming the base 292 figure is torque, not hp ??
 
Brooks James said:
I'm assuming the base 292 figure is torque, not hp ?
Click to expand...
Yes the torque number for the article in the link, here's the hp


HORSEPOWER SUPERFLOW 901 DYNO-TESTED AT WESTECH
RPMBASEMOD 1MOD 2
2,000112
2,500137
3,000164193192
3,500182224227
4,000189248252
4,500186265274
5,000179271282
5,500262270
 
GTX JOHN said:
If it was me, I would run the stock intake and carb.
I also would run the original 340 cam if it is in good condition
with new lifters.
These cars would run to 6000 easily with stock springs and camshaft
and were good daily drivers that would run 13s in quarter if well driven
and tuned!
My son and I both run NHRA legal stockers that run Mid 10s @ 125
with stock intake and carb plus stock lift intake = Nothing wrong with intake
and carb.
Click to expand...
John,

I've got all of the stock components except for the carb. It had a single inlet, spread bore holley on it. I'll have to look at the model number to determine the CFM rating. After getting the intake and oil pan off, the engine is going to have to be gone through. Unfortunately, it was stored without a distributor, so mice found their way into the intake valley and proceeded to drop all sorts of debris through the engine.
Could you provide any tips regarding the heads themselves? Any porting to the stock intake? You can PM me if you don't want to post about it. I ran the #s on the transmission last night and it's the original 340 spec 727 with the factory "high stall" converter, which is about 22-2400 RPM per what I read in Mr. Hand's 727 book.
 
Correct on the Converter.
All I would do on the Heads would be a good valve
job (Seats not too narrow) and open up with a cutter the
area behind the valves.
 
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