340 stock cam question

[John Hogan]

John,Please post your findings when you call Melling. Information is always good.

Well, the call to Melling tech support was pretty useless. The tech said they use the Chrysler specs on the SPD-22. I told him that with all the years and models of 340 and 360 they show the cam to cover (1970-1981) I was sure Chrysler used a different cam in a 1970 340 Challenger vs. a 1981 360 Ramcharger. He claimed that they get their info from Chrysler and the SPD-22 was the same grind used in all the years and models they show in their application list. Asked if he meant it would work or was it actually the same cam profile, he claimed the cams were all the same. I'm not buying that, but my research goes on.

 

[PRHeads]

Imo, you’re over thinking it.
All 340’s except the 68 4 speeds used the same cam.
And yes, that same spec cam was used in many other HP SB’s thru the years.

 

[John Hogan]

Imo, you’re over thinking it.
All 340’s except the 68 4 speeds used the same cam.
And yes, that same spec cam was used in many other HP SB’s thru the years.

Thanks, after 30+ years out of the engine building hobby I'm sure I am overthinking it! Last engine I built was during the AOL dial-up days and online research didn't exist. Just went to the local speed shop and took their advice. What threw me was when the tech guy specified a 1981 truck or van with a 360 would have the exact same cam as a performance car. Seemed like the question of an HP 340 cam was something he just didn't understand. Doing some research it seems the SPD-22 is close to the factory HP cam with about the same lift and a bit more duration. Thanks everyone!

 

[JC Boatguy]

Just gonna throw in my 2 cents...
In the 80s I drove my high comp. (10.3)
340 daily. It had a re-ground cam that was approximately 284 dur, 445 lift, 4 speed and 3.23 SG. I balanced the engine where I worked and once you got rolling it wound quickly to 6500 rpm! But...here's the butt, for a driver, I would think there is a better grind to produce a stronger bottom end...more of an RV grind? Anybody wanna chime in on that?

 

[Dodge Bros]

At one time we use to put the 204/214 cams in almost every stock mild performance engine we built. Never used anything but stock valve springs with those cams. Lost track of how many we used. One was a 360 for a 73 Road Runner with the 204/214 cam, stock 2bbl valve springs, log manifolds, performer intake with 2.73 gears. It was ok. But after being around both the SPD-22 and and 204/214s in low compresssiom engines, I can’t say that smaller cam helped the low end power over a stock 340 cam much, and does loose some top end HP. FWIW.. If I did the 360 in 73 Road Runner over again I would use the 340 cam over the 204/214.

The SPD-22 was used in a lot of low compression 340 and 360s.

Adding the the 204/214 to a 340 is making the car have a bit less HP than it was when it was stock. Not too cool.

 

[Krooser]

Have Oregon Cams (or another cam grinder) regrind your stock cam.

A stock Mopar cam is ground to take advantage of the 903 lifter diameter...those big name shelf cams are ground for a Chevy lifter. Big difference.

Make sure yours is made for the Mopar lifter.

 

[davek]

OK gang, I haven't built a motor in 30 years. And all the motors I built back then were for street/strip. I always ran Mopar Performance cams. Now I have a 1973 340 in a Road Runner I'm currently restoring and I plan on using it for cruising and possible road trips. This car won't be visiting the strip. Stock bore, stock compression ratio, stock heads. I am looking for a cam that will have good drivability and idle as well as lower RPM torque. I see Melling has a stock grind replacement cam (SPD-22) with the following specs:

Exhaust Duration - 289 deg
Intake Duration - 279 deg
Exhaust Duration at .050 Lift - 220 deg
Exhaust Valve Lift - .444
Intake Duration at .050 Lift - 209 deg
Intake Valve Lift - .429
Lobe Separation - not listed

They also offer a cam (MTD-1) with the following specs:

Exhaust Duration - 288 deg
Intake Duration - 278 deg
Exhaust Duration at .050 Lift - 214 deg
Exhaust Valve Lift - .443
Intake Duration at .050 Lift - 204 deg
Intake Valve Lift - .421
Lobe Separation - 112 deg

Your thoughts on if their MTD-1 (classified by Melling as a torque towing camshaft) would have any advantage over the stock cam for my intended usage? Or any other recommendations for a good cam? I have read there seems to be lots of quality issues lately. Thanks!

What did you end up using on your engine? The cam is my last piece for me to buy. Mines a stock 318 bored 30 over. Did you have to change anything on the heads for the cam? thanks Dave

 

[John Hogan]

What did you end up using on your engine? The cam is my last piece for me to buy. Mines a stock 318 bored 30 over. Did you have to change anything on the heads for the cam? thanks Dave

Haven't fired the engine yet. Been working on the rest of the floors, body work and painting the engine compartment and jambs. Discovered that the cam in the engine was a Comp Cams 268H. From receipts I found it seems the last rebuild by the previous owner was in 1994 at an unknown mileage. The Comp is in excellent shape and with all of the horror stories of newer cams getting trashed during breakin I am seriously considering reusing it. Had a local machine shop upgrade the heads to 2.02 valves. This whole answer isn't really much help for your question, sorry!

 

[toolmanmike]

At one time we use to put the 204/214 cams in almost every stock mild performance engine we built. Never used anything but stock valve springs with those cams. Lost track of how many we used. One was a 360 for a 73 Road Runner with the 204/214 cam, stock 2bbl valve springs, log manifolds, performer intake with 2.73 gears. It was ok. But after being around both the SPD-22 and and 204/214s in low compresssiom engines, I can’t say that smaller cam helped the low end power over a stock 340 cam much, and does loose some top end HP. FWIW.. If I did the 360 in 73 Road Runner over again I would use the 340 cam over the 204/214.

The SPD-22 was used in a lot of low compression 340 and 360s.

Adding the the 204/214 to a 340 is making the car have a bit less HP than it was when it was stock. Not too cool.

That SPD-22 is a nice cam. More duration than the 68 340-4 speed cam but less lift. It will idle a bit more aggressively than the 340 cam but the less lift will be a bit easier on the valve train. That SPD would work fine in a 340/360 but you might not want it in a 318 unless you have a converter and different rear gears to make it work. In fact a looser converter in a 340/360 with that cam would make it happier off the line. Here's the 68 manual transmission 340 cam. It sounds great, idles a little ragged, and would like a converter to make it work better.