Recommend a cam for my 340?

[Chargerguy74]

Can anyone recommend a camshaft to wake up my 340? I'm not looking for anything too crazy, just a little wilder than stock. I just took it for a rip today and I'm not really happy with it. It's a bone stock 1970 340, X heads. I am going to be running an Edelbrock performer rpm air gap intake, Holley 650 double pumper, and TTi step headers. Here's a short video. The quality blows, I know, I plan on getting a go pro soon.

https://www.youtube.com/watch?v=b7bCsqlQXCU

[Challenger340]

I watched your video.
no offense intended... but how do you know this is a "bone stock" 1970 340 X Head Engine ?

I guess my question really is...
Who rebuilt it ?.... and using what parts ?

For a Cam Rec....
* remove all 8 spark plugs
* Wire the throttle plates wide open
* dis-able the ignition system
Then do a compression test on each cylinder... "4 bumps only" of the Compression tester needle.... per cylinder !
Look for the 1st "bump" of the needle, to be 75% of the 4th and final bump..... and record.

Need to get at least an idea of current cylinder filling and dynamic compression, which will assist anyone making a Cam Rec.
Hopefully Ron(FireFighter3931) will chime in also.

[Chargerguy74]

Just going off the info I was given.  But, you're very correct. I can't speak for what happened to the engine in the early to mid 70s. From the late 70s to now it hasn't been touched. So, really, I can't say bone stock with 100% certanty. But it's highly likely it is. No rebuild I am aware of.

[Chargerguy74]

I'll grab compression numbers tomorrow.

When you say 4 bumps. Are you saying take a reading per cylinder 4 times? Or bump the engine 4 times, to give me one reading on the gauge, and record that?

[justcruisin]

Test each cylinder once, crank the engine over on the starter motor until you have had 4 pulses on the compression gauge. (4 compression strokes).

[cudaken]

74, have you checked the ignition system far as base timing and advances? Lot of people will leave untapped HP on the table.

While a 340 is a good running motor (I have never owned one) if the Charger is a 74, well that is a lot of weight.

Where are you unhappy with the power, of the line, mid range, top end or all I have listed?  What king of exhaust are you running, 70 HP manifolds or other?

Charger did sound good, where you short shifting?

Cuda Ken

[Chargerguy74]

Yeah, I was short shifting. The tach wasn't working and I haven't installed my Rev-n-nator yet. I recently blew an engine the day before I planned to install a rev limiter. It's tach sporadically worked, but I just missed a shift. So I'm a little gun shy to stay into it too long. But my issue with the 340 is off the line, I have a hard time breaking the rear end loose. Top end is fine, and the 150mph speedo is put to good use. The rear is a 3.55 sure grip 8 3/4. The tires are worn and could use a good beating before I swap to the new skins.

I hope there is a lot of untapped power that can be had from tuning the ignition. The engine runs like a 40 year old engine. It was a rolling start, and I mashed that poor pedal into the floor in 1st. I haven't tweaked much yet as I plan on pulling a lot of the factory components off, like the intake and carb. The previous owner's friend rolled his '70 Challenger 340 4 speed in the late 70s. He rolled it into his own 340 4 speed 'cuda, as the story goes. This was the same time the rear frost plug on the '74 360 corroded. So the 340 was swapped into the 74 and the 360 put into storage. Factory HP exhaust manifolds, with some downstream exhaust components missing lol. Getting ready to install the TTi setup. The more I think about it, the more I think I should yard out the 340 and drop in the 440. And if that doesn't make me happy, then it's time for a new hobby (yeah right). I'm sure someone out there would love a running '69 cast 340 and freshly rebuilt 833 for a project.

[Challenger340]

Those Compression numbers... taken/recorded with the procedure as described, will tell you LOTS about whether to proceed with the 340 Cam upgrade, or cease and desist to contemplate a BB swap ?

The '69 & '70 340 Engines... if in any shape at all, with the Factory Camshaft will pump about 150-155 psi. If you see those numbers, then "game on".
But also be aware, that any Cam change from that point on with the heavy B-Body, would also "like" a rear gear change.

[randy73]

When was the last time the car had a tuneup and what carb and when was the last time it was tuned up?

Reason I ask, is when I got my charger it was a dog. Carb was so gummed up, it could hardly get out of its own way, replaces carb and tuned it and runs great now or at least did before I started restoring the car.

Forgot, are the exhaust manifolds from the 70 or 74?

[cudaken]

74 few numbers for you.

1970   HP    Foot Pounds
340     275  340 @ 3200
383     335  425 @ 3400
440     375  490 @ 3200

340 is a great engine, the above numbers are publish number by Chrysler and they are some what optimistic on the BB engines. 340 did make the numbers listed above in good state of tune. Most 383's came in around 275 to 310 HP and 440's 330 to 360.

My self, I would think about BB power and that 340 with the X heads is worth a pretty penny. But, do a compression test and don't sell it short.

Cuda Ken   

[Chargerguy74]

I really appreciate all the help. I wasn't able to get out to the shop today and check the compression. So it'll have to wait until the weekend. I'll check the compression and do a good tune (to the best of my abilities) and see if there's much improvement. Itll most likely be done with the new intake and Holley in place. I do believe the exhaust manifolds are the 70s. I checked the casting numbers 4 years ago before puting the car in storage, and if my memory serves me correct they were the 70s. The exhaust on the drivers side was also rubbing quite the flat spot into the torsion bar. Zero clearance.

I feel like I jumped the gun on the idea of swapping cams. Hopefully I did. It would just be a very opportune time to swap with all the suspension upgrades, etc about to be done to the car.

[Chargerguy74]

Sorry it took so long to get these numbers. Was able to line up a helper today to turn the engine over. The engine was cold. The compression numbers are as follows.

Cyl:

1-15psi (yes, 15)
2-117psi
3-95psi
4-107psi
5-120psi
6-125psi
7-110psi
8-92psi

The engine is getting pulled and sold. The 440 will be going in now. I'm pretty impressed that it ran so well on 7 cylinders.

[Chargerguy74]

Any ideas on a fair price for the 340?

[Nacho-RT74]

why not rebuild ?

[Chargerguy74]

I have a rebuilt 440 sitting on the stand. So I think it's kind of pointless to rebuild the 340.

[Nacho-RT74]

mmmm, well, if is not a matching number..., but I'd rebuild anyway ... save maybe for later. 340s are not everywhere

[Chargerguy74]

Very true.