360 with 340 camshaft thoughts?

[dustadude]

So years ago I rebuilt my 74 360 block, 30 over, had the heads machined, and then
ordered a 340 cam with matching lifters and spring . The cam was I believe
was P4452782, with advertised duration of 268/276, 44 overlap, 114 centerline, lift. 429/.444
The carb on top is a thermoquad.
What do you guys think of the cam in the 360?

 

[krazykuda]

It will run nice. Put some Rhoades lifters in it also.


I ran a stock 340 cam in a 318 with 9.2 compression, and 360 heads and Rhaodes lifters. It idled at 22.5" Hg and ran great. 17.75 MPG with 2.76 axle.

Run a good dual plane intake.

 

[fratzog lover]

The 3.58 stroke will make the cam a little milder, but still have good low end torque. What kind of engine are you looking for. You should have a good, if mild, street cruiser.

 

[krazykuda]

The 3.58 stroke will make the cam a little milder, but still have good low end torque..

The stock 340 cam also came in the 360 4 bbl engines such as Lil Red Express trucks. they ran great and did quarter mile in 14.5 with 3.55 gears. :burnout:


It will run fine in a 360....

 

[66fs]

So years ago I rebuilt my 74 360 block, 30 over, had the heads machined, and then
ordered a 340 cam with matching lifters and spring . The cam was I believe
was P4452782, with advertised duration of 268/276, 44 overlap, 114 centerline, lift. 429/.444
The carb on top is a thermoquad.
What do you guys think of the cam in the 360?

Great combination. I've put a lot of street 360 engines together with that cam, a TQ, a factory intake, and dual exhaust. They all ran great, good torque and power.

 

[RustyRatRod]

The stock 340 cam also came in the 360 4 bbl engines such as Lil Red Express trucks. they ran great and did quarter mile in 14.5 with 3.55 gears. :burnout:


It will run fine in a 360....

All without Rhoades lifters. They have their place, but certainly not on a tiny camshaft like that, IMO.

 

[mguner]

The 3.58 stroke will make the cam a little milder, but still have good low end torque. What kind of engine are you looking for. You should have a good, if mild, street cruiser.

True, the larger displacement and stroke can handle a little more cam before loosing bottom end.

 

[rumblefish360]

All without Rhoades lifters. They have their place, but certainly not on a tiny camshaft like that, IMO.

No doubt I agree. Krazy must be thinking about the other cam with similar specs called the "Replacement 340 cam." This one is the broom stick stocker.

So years ago I rebuilt my 74 360 block, 30 over, had the heads machined, and then
ordered a 340 cam with matching lifters and spring . The cam was I believe
was P4452782, with advertised duration of 268/276, 44 overlap, 114 centerline, lift. 429/.444
The carb on top is a thermoquad.
What do you guys think of the cam in the 360?

This is what I know. All 4bbl. 360's came with that cam. The 360 lacked compression, valve size and a decent exhaust.
This is what I think, it'll perform great with the missing parts above. Otherwise, you have a stock engine. Use the above mentioned replacement 340 cam with more duration and a slight less lift. IF you intended to stay with a purple cam. Otherwise, my choice would be the XE268H.

 

[66fs]

No doubt I agree. Krazy must be thinking about the other cam with similar specs called the "Replacement 340 cam." This one is the broom stick stocker.



This is what I know. All 4bbl. 360's came with that cam...

Not true most 360 4 barrels came with the 360 2 barrel cam.

 

[rumblefish360]

66fs, where do you collect your infomation from?
My info comes from the how to rebuild/hot rod your SB mopar.
If the book fails in your eyes, please provide a check able creditable source.
Thanks

360-2bbl. ..... 71-74 252/256 - .410/.412
360-4bbl. HP 74-75 268-276 - .430/.444 same as the 340
360- 2bbl. .... 75-78, 252/252 .410/.410
360- 4bbl. .... 76-80, same as the 74-75 HP 360
360, ............ 76-80, 252/252 - .410/.410

So pretty much if you had a 4bbl. It so appears you have the 340 cam. Am I wrong? According to the chart above? It clearly states 4bbl. or H.P. or 2bbl.

 

[66fs]

I'll check, mine is from working back in the day. If you wanted the 340 valve train you wanted the E58 360. There were many other differences from pistons, valves, cranks, windage trays, double roller timing chain, and rings as I remember.

http://www.forabodiesonly.com/mopar/showthread.php?t=249176

 

[rumblefish360]

Yea!, I know that package. A nice set of goodies in the engine. I only had one of those in my hands. I actually have it away to a fella who spun a bearing racing his Duster. He didn't know you can not take a in-modified block to 7000+. All well, live and learn.

For sure, what ever you can dig up would be great! Thanks

 

[dustadude]

Man you guys are great, I post this and get a ton of great information! Can't wait to get my TQ carb issues worked out so I can actually drive this beast. I'm just looking for a streetable cruiser, as close to a 340 as I can get with a 360 since thats what I have for now

 

[OldmanRick]

All the cams mentioned above are mild, by today's standard's, except the "retro" grind. Even with a low comp 360, the original 782 cam will be fine with at least a 3 series rear gear. The T/Q will be great with it, and as long as the exhaust can breath, you'll have "340" performance, especially if you push your initial timing & curve to the maximum it will handle with your available pump fuel.

 

[krazykuda]

No doubt I agree. Krazy must be thinking about the other cam with similar specs called the "Replacement 340 cam." This one is the broom stick stocker.

No, my engine used the camshaft out of my brother's 78 Lil Red Express. It is the same as the 68 340 auto cam.

 

[krazykuda]

All without Rhoades lifters. They have their place, but certainly not on a tiny camshaft like that, IMO.

They do help with the larger cams, but also with the smaller cams.


With a stock 318 short block except for 10.5 forged pistons, I put the old cam from my borther's Lil' Red Express and used the 2 bbl heads and carb. It idled at 24" Hg, but would overheat when the outside temps got above mid 80's.

I put 360 heads and stock square bore dual plane intake and it only dropped idle vacuum to 22.5" Hg. I was able to run a 10.5 power valve and got good MPG.

Higher vacuum is due to higher velocity in the intake. Velocity is torque....


Rhoades lifters can help even with "small" stock type cams also.

 

[OldmanRick]

kk, I should have asked this a long time ago, but how do the Rhodes sound with mild cams? The only engine i was around using them was a Pontiac with a fairly stout grind and a non-adjustable valve train. It was a "hair" noisy at low rpm's.

How much do you think a proper preload is important for those lifters? And, would a adjustable system really make the most of what they were designed to do?

After all, most guys don't want a car that idles like Grandma's with a valve tick....

 

[krazykuda]

kk, I should have asked this a long time ago, but how do the Rhodes sound with mild cams? The only engine i was around using them was a Pontiac with a fairly stout grind and a non-adjustable valve train. It was a "hair" noisy at low rpm's.

How much do you think a proper preload is important for those lifters? And, would a adjustable system really make the most of what they were designed to do?

After all, most guys don't want a car that idles like Grandma's with a valve tick....

I really don't notice the ticking myself. I run them with High volume oil pumps and high pressure springs.

The guy that sold me on them used to run two hood pads to cover up the ticking sound, or just tell others that it was a solid lifter 273 engine.


I've run them with stock 340 cams up to the .484/284 MP cam. They really helped with the .484/284 cam. With regular lifters it idled choppy at 1100 rpm at 10.5" Hg, with Rhoades lifters, it idled much better at 13" Hg at 800 rpm.


As far as preload, I've run them with stock stamped rocker arms. They were able to tolerate the variation of stock rockers, and should work fine with adjustable. I did put them in dad's Hemi with adjustable rockers and they were fine.

 

[oldkimmer]

.................I have used the stock 340 cam in many small block builds.....Its a great cam...........kim.............

 

[OldmanRick]

Thanks for the info Karl. The Pontiac I was talking about was a low comp 455 that had a cam (Crower) that was pretty comparable to the 484/284. I don't know a A/B comparison on it with the lifters since it was installed all at once, but it did have enough idle quality to work well with the stock converter.

 

[rumblefish360]

I have used the Rhoades lifters twice before. The largest cam I used it with was a oval track Purple cam. 288/.499-108 installed @ 106, a 1/4 mile flat track cam. That thing idled like a lumber jack on crack having withdrawals. Once I had the Rhoades in there, it mellowed it out enough to be drives me by any body.

The preload can be varied. Best thing I do is read up on them at there site. It will help explain it all.
I myself was not bothered by what some consider to much noise. I didn't think them loud at all. Noticeable yes, but not annoying.

 

[rumblefish360]

Man you guys are great, I post this and get a ton of great information! Can't wait to get my TQ carb issues worked out so I can actually drive this beast. I'm just looking for a streetable cruiser, as close to a 340 as I can get with a 360 since thats what I have for now

Like I say, the 360 was a day late and a dollar short. It is missing some compression, valve size (intake) and a good exhaust. If equipped like a 340, it will do very nicely. Keep the ratio @ 9.5-1 or less for today's fuel. Dual exhaust should be mandrel bent. Upgrade your ignition! Even the factory intake is capable. It is a good part. Right now the hardest part you have to deal with is the TQ. Finding a good one is the hardest part then followed by setting it up correctly. Once set up and dialed in, it will be an excellent street carb. There really is no reason not to out run a 340 at that point.

The OE camshaft is pretty melo and it will not need the Rhoades lifters. It should idle very well. Drive smoothly any where at anytime in any weather.

 

[66fs]

Yea!, I know that package. A nice set of goodies in the engine. I only had one of those in my hands. I actually have it away to a fella who spun a bearing racing his Duster. He didn't know you can not take a in-modified block to 7000+. All well, live and learn.

For sure, what ever you can dig up would be great! Thanks

From what I could find in the racing manuals, a 1974 Plymouth factory parts catalog, and a 1978 Motors manual, there was a 360 4 barrel option with or without HP (High Performance) from 1974 to 1978. I only have books to 1978. Only the HP 360 had the 340 cam and valvesprings, I assume the double roller timing setup also. My 74 parts manual still shows the special thrust plate bolt with the hole drilled through for extra chain oiling. Another twist is that for California, the HP 360 also has the 2 barrel cam???

 

[krazykuda]

Another twist is that for California, the HP 360 also has the 2 barrel cam???

Probably due to their stricter emissions.... :banghead:

 

[66fs]

Probably due to their stricter emissions.... :banghead:

Very little doubt...