340 Cam Kits which ones work with a stock block

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68 Coronet RT

68 Coronet RT

68 GTS # 508 in Registry
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Upstate New York
Looking for a good cam kit for my stock block 340 with stock exhaust manifolds and stock intake but willing to change the intake if need be. What I'm looking for is a cam kit that will give me the nice cam sound but don't want to sit at a light and rock and roll, want to be street able. I know I will have to change springs and rocker arms and lifters not an issue. Car does have a 2 1/2 " TTI exhaust system all the way with dyno max mufflers. She is a automatic with a nice shift kit but not sure about converter. Rear end has 3:91 posi.
 
Crane Z-268-2 is one decent choice. A bit milder than other 268's.
Not aggressive ramps so not a cam to tend to have issues. Will work well with a lower stall converter. My son's 340 has a 2200 RPM stall and this cam just motors right out from a stop.
But I am not impressed with the hydraulic flat lifters being used these days. See the thread on lifters running at this time.
 
Do you have the stock converter in the trans?
If so, are you willing to swap it for a higher stall unit?
FWIW, the factory intake is very good.
 
rumblefish360 said:
Do you have the stock converter in the trans?
If so, are you willing to swap it for a higher stall unit?
FWIW, the factory intake is very good.
Click to expand...

I have no idea what's in the car for a converter, what ever is in there was there when I purchased the car last year. Do I really want to drop the tranny to change the converter, if I was going to go to the track every weekend I might but I have no intensions of going to the track. Just play around on the street so no
 
Well, changing a converter isn't a track thing only. A higher stall just allows the engine to get into it's power making band a lot quicker and easier. I have a 2400 in my wifes car right now. It runs and drives like a normal car with the upgraded parts smoothly. With the 3.91's, you have a higher ceiling on what can be done. but a converter change would be needed for the bigger camshafts. Without a converter change, your limited. I would suggest no larger than a 218 @ .050 duration cam.
(Generally speaking, that is in the area of 1500/1800 - 5000/5500 rpm. Depending on how made the camshaft.)

That, "Nice sounding cam" sound often considered "That Muscle car sound" which is a cam ground on a 110 LCA. Most cams are done this way. A more muscle sounding, or more radical idle will have the LCA @ a 108.

next question......

Would taking the heads off to modify them for valve springs be OK?
This maybe a needed evil and a lot depends on the spring used.
 
Lunati voodoo is about the only source of off the shelf cams optimized for the Mopar .904 lifter
(or Hughes) in your street duration sizes
many others (Howards, Engle, Bullit, crane) can do custom but comp has nothing smaller than their HL series
Many others like ISKY have nothing even custom

would you recap your heads, gears, body or weight and how do you drive it?
is your 340 68 vintage compression or late lower ??compression or has anyone ever changed pistons
what is your cranking compression?
The factory cam may be 209 @ .050 but it has very long ramps which bleeds off dynamic compression
anything done to your heads?
willing to cut your guides for more lift and viton seals?
 
Rumble suggested [email protected] without me knowing the details you can go from the way obsolete comp 268H with less lift than stock (chevy grind)
to a Hughes SEH 1629BL-12 with .495 lift on the intake
the Voodoo 60302 (may be a RB number) is .475 lift
Howard has a lobe with a half inch lift at [email protected]
several good choices- post up the details and get dialed in
 
Wyrmrider said:
Lunati voodoo is about the only source of off the shelf cams optimized for the Mopar .904 lifter
(or Hughes) in your street duration sizes
many others (Howards, Engle, Bullit, crane) can do custom but comp has nothing smaller than their HL series
Many others like ISKY have nothing even custom

would you recap your heads, gears, body or weight and how do you drive it?
is your 340 68 vintage compression or late lower ??compression or has anyone ever changed pistons
what is your cranking compression?
The factory cam may be 209 @ .050 but it has very long ramps which bleeds off dynamic compression
anything done to your heads?
willing to cut your guides for more lift and viton seals?
Click to expand...

OH! By the way, welcome aboard Wyrmrider!

By the way 68 Coronet RT, this, "cams optimized for the Mopar .904 lifter" is not allways needed to do. Certainly not for everyone or for an every day, daily driver. While the steeper ramps and quicker valve openings certainly do provide more power, it only shows up if your going to really taking advantage of it all. It's more Hype than anything on mild mills. The quicker cam ramps are tougher on the valve train. You should have no real worries though as long as the valve train geometry is dead on.
 
Wyrmrider said:
Rumble suggested [email protected] without me knowing the details you can go from the way obsolete comp 268H with less lift than stock (chevy grind)
to a Hughes SEH 1629BL-12 with .495 lift on the intake
the Voodoo 60302 (may be a RB number) is .475 lift
Howard has a lobe with a half inch lift at [email protected]
several good choices- post up the details and get dialed in
Click to expand...
Of course. Limitedinformation, limited answers. Still, I'm asking questions.
Having used that duration cam several times, it has work very well in low compression 318's to mid level (10-1) 360 engines.

And yes, even though you love to tout key words like, "Chevy grind", "MoPar grind", "904 ;ifter design", pushing someone in that direction under brow beating posts doesn't help or make it correct. Yup, even a Chevy grind cam will make power in any engine it slides into. There a fav by grinders for more than just ease of production. They also last due to not being stressful on other parts and less than perfect builds.

Don't brow beat and shame people into what YOU think is the best cam.
 
rumblefish360 said:
Well, changing a converter isn't a track thing only. A higher stall just allows the engine to get into it's power making band a lot quicker and easier. I have a 2400 in my wifes car right now. It runs and drives like a normal car with the upgraded parts smoothly. With the 3.91's, you have a higher ceiling on what can be done. but a converter change would be needed for the bigger camshafts. Without a converter change, your limited. I would suggest no larger than a 218 @ .050 duration cam.
(Generally speaking, that is in the area of 1500/1800 - 5000/5500 rpm. Depending on how made the camshaft.)

That, "Nice sounding cam" sound often considered "That Muscle car sound" which is a cam ground on a 110 LCA. Most cams are done this way. A more muscle sounding, or more radical idle will have the LCA @ a 108.

next question......

Would taking the heads off to modify them for valve springs be OK?
This maybe a needed evil and a lot depends on the spring used.
Click to expand...

If I knew what was in the car as far as a converter it would be different as far as what I would put in it. I would hate to drop it then only find out what I bought new is what's in there. This is my first automatic. My other mopars were 4 speeds, What mods are you talking about to the heads for springs ? If you are talking changing the springs I don't need to pull the heads to do that. The cam kit I had in my 440 RT I had to change the springs and I have the tools to change them on the car that's not a issue and I would rather change them as this motor in my Dart has never been apart it's all original as is the interior and all the sheet metal. The cam I had in my RT was from Straight Line Performance which is now Competition Components, the cam had Lobe lift .335 intake and .335 Exhaust, Valve lift was .503, Adv.Dur 270 In 284 EX, [email protected] 226 In. 238 Ex. LBC 108 IN. 116 Ex. It was a adjustable hydraulic lifter set up with new springs and rockers. It really ran good but you could not tell there was a cam in it unless you got close with the hood up and you could here a little clatter from the lifters.
 
you can design an easier on the valvetrain master or a more velocity without increasing acceleration or a faster action or anywhere in between
All I was trying to say is there can be a wide range of profiles with 218 (or any other) @.050
and
seat timing is more important
268H
268 AH 10
oh please something from this century
those old grinds can make hp but cost torque- or vice versa

OP stock 340 converter to start don't spend big bucks till you find out where you motor stalls a stock converter
2ed
It's not changing the springs it's that they are so short and there is not much clearance between stem seal and keeper
someone weigh in about how much lift you can utilize without cutting the guides
 
Wyrmrider said:
you can design an easier on the valvetrain master or a more velocity without increasing acceleration or a faster action or anywhere in between
All I was trying to say is there can be a wide range of profiles with 218 (or any other) @.050
and
seat timing is more important
268H
268 AH 10
oh please something from this century
those old grinds can make hp but cost torque- or vice versa

OP stock 340 converter to start don't spend big bucks till you find out where you motor stalls a stock converter
2ed
It's not changing the springs it's that they are so short and there is not much clearance between stem seal and keeper
someone weigh in about how much lift you can utilize without cutting the guides
Click to expand...

The stock 340 cam has a Intake lift of.429 and exhaust of .444 according to my service manual. The cam I'm looking at is a purple shaft with a Intake and Exhaust lift of .484 or a cam from another manufacturer with something very similar
 
Excellent post Wyrm.

Springs. To add a note to it, all valve spring are not created the same. Height, width, diameter on the inside, outside, installed height, bind distance, etc.... Sometimes it requires some work where the spring sits on the inside requiring the use of a cutter.

That would require the head to be removed. Goose your spring wisely. Look closely.

If you do t know the converters stall, I will make an error on the side of caution and suggest a smaller cam that will work with what could be considered a low stall stock converter. Hence, the [email protected] duration.

In the far past, old tyme member Mike Beck ran low 12’s in a race only Duster with a Crane cam. A split duration @ 216/228-.454/.480-112. In, IIRC, a 360.

I have been long a manual trans 4spd guy. I understand where your at. I took my problem (with advice from long time friends advice) to a local shop (ProTorque High Performance Drag Racing Torque Converters) and told them everything they needed to know except having a Dyno sheet. Which they chuckled and told me it was OK. They said, “We got your back.” They modified the stock converter to suite. Now rated to 650hp.
 
72Dart6pack said:
Go as big as possible without hitting the pistons. Small cams are a waste of time.
Click to expand...



I'm sorry but I gotta LMAO when I read posts like this. My 408 ran 9.80's with a 520 lift Racer Brown with both W2 heads and Edelbrock Heads. My Sons 3250 pound Duster went 10.40's with his 520 lift cam in his 360 with a stock crank and flat top pistons.
 
pittsburghracer said:
I'm sorry but I gotta LMAO when I read posts like this. My 408 ran 9.80's with a 520 lift Racer Brown with both W2 heads and Edelbrock Heads. My Sons 3250 pound Duster went 10.40's with his 520 lift cam in his 360 with a stock crank and flat top pistons.
Click to expand...
Where did the heads flow quit?
 
If the Straightline cam was not enough idle for you, NONE of the 268 or voodoo recommendations are going to be good.
 
If you just want the sound without the work I suggest this...




This is what an LS sounds like when installed in a Mopar...
 
Wyrmrider said:
Rumble suggested [email protected] without me knowing the details you can go from the way obsolete comp 268H with less lift than stock (chevy grind)
to a Hughes SEH 1629BL-12 with .495 lift on the intake
the Voodoo 60302 (may be a RB number) is .475 lift
Howard has a lobe with a half inch lift at [email protected]
several good choices- post up the details and get dialed in
Click to expand...
268H Comp High Energy, is a safe grind , and produces good torque, while remaining streetable . Next choice: The k6900 Summit cam 204/214 @.050 is generic, but smooth ramps. That's a personal favorite, on a budget. It makes torque, that's what you need.
 
Some notes working backward

Abody bomber

268H is a safe grind, good torque but not great torque especially with a lower compression motor

look when it was designed and what gas was available

The Summit is better than buying exactly the same thing from Edelbrock, Elgin is even less expensive

an even older design than the 268 H I'd do a regrind first Like the stock cam it has really long seat timing for the amount of lift or duration at 200 Needed compression back in the day and that has not changed.

Agree with crackeback – but I do not buy cams for the sound

and the 218 was a strawman till real data shows up- just for discussion- I can even agree with Rumble about that:)

72Dart r has a good point use as much lift as you can but no more- and put it in correctly as advance or retard changes valve clearances

what is a small cam? Short at .200 IMHO we can use limited lift by rolling the nose over while still have the valve open a bunch where it counts where the piston is really moving

Duration is simple more duration moves up the torque curve- how much low end do you want to live without?

Excellent post rumblefish360

68CoronetRt Purpleshafts are better than most out there but they are pricy and lobes are dated

one reason is that there are better springs today- and better heads if you use head flow to help spec a cam The stock 340 cam has VERY LONG RAMPS and as you say not much lift

any idea what your cranking compression is--- stock heads, thick gaskets now? Any idea what your compression really is?

thanks for the tip about Competition components- not in my database

I'll post some in the range you are looking at later today but IMHO you are not ready to make a choice



a Note on CRANE

nm9sheham

The reason that the crane 268 is milder is that it is! Crane measures duration .004 off the basecircle whereas Comp measures at .006 so a 268 Comp is BIGGER than a 268 Crane

and Engle and Isky measure at .008 (or more in IskyMegacams) and MOPAR (which is completely different)

They are not aggressive ramps even for the Chevy lifters they were designed for

What they are is that they are SMOOTH for the time they were designed- Harvey Crane was ahead of the game as to jerk etc (at least as far as advertising it) and was in fact less hard on the valve train than Clay Smith, Howard and some others we could mention- Isky made (and still sells the same thing) cams that were easy on the valvetrain by stretching out the duration (just like the factory did)

That's why Isky Megacams rev well and are reasonably stable when over revved

so you gear low or a more modern grind will eat you off the corner- and change your springs
 
so key thinks is to determine how much lift you can use- stock piston 340 guys speak up

.484 Direct Connection Cam

284 MOPAR duration (which cannot be directly compared with anything else except other MOPAR

294 industry duration

143@200 measured



some other cams with about the same whatevers

Comp Purple Power 6884 shorter seat with fatter duration than MOPAR, limited lift

.485 .323 lobe [email protected] [email protected] 154@200

There is also Voodoos with .494 lift, .510 lift, .533 lift with 287@006

Howard .518 lift 271 duration [email protected] several other choices note the short seat duration

Comp HE HL

[email protected] .363 lobe [email protected] [email protected] 159@200 shelf with 110lca would take some head work

.525 [email protected] 440 source smallest .904 lifter offering appears to be comp XE-HL lobe
275/ 287 @.006 149@200 110lca intake closes 64ABCD comp XE275XL
 
The 284/484 will definitely give you a choppy idle. It should be in the 240-242 range at .050. If you do buy that cam , DO NOT get one other than the 108 LSA model. In a stock 340, grab a degree wheel and install it at 100-102 ICL.

Put plenty of initial timing on it and it will be decent down low.

If you don't already have the cam, look for something other than a MP grind. There are plenty of similar grinds from other companies out there.
 
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