360 cam

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Brayden Holden

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I and a 1978 360 chrysler with standard heads and flat top pistons etc, I need to replace the cam shaft, I have been doing some browsing on the net. I am wanting to try make it lumpy. I like the look of this package ...

COMP Cams Thumpr Hydraulic Flat Tappet Cam and Lifter Kits K20-600-4

Will this be alright in my engine? Or will this require some work to the heads? Or will it all work fine?

Thanks in advance for anyone’s input that can help me as at the moment I am not wanting to buy different heads.

I have put in a photo of my block engine number and head number
 
The stock heads will work fine with a good valve job and install the springs that come in the kit to match the cam...


Look up the manufacturer's recommendations:

20-600-4 - Thumpr™ Hydraulic Flat Tappet Camshafts

Pay attention to the notes on the bottom of the page especially the last one stating it needs adjustable rockers...

They recommend stock converter = ok, 2000 stall better.... and a gear (3.55, 3.91, or 4.10)....


You may want to go with a little tamer cam or throw in some Rhoades lifters to tame out the idle without sacrificing top end... But the Rhoades lifters will also make it less lumpy which is opposite of what you want...

If you go with too big of cam without matching the other components, your car will fall flat on it's face... If you run a smaller cam your car will be faster than over camming it... .

Too small of a cam will just run a little short on the top end... Too large of a cam will run bad across the whole RPM range - especially with too small of rear end gear...

Don't get too eager to get a lumpy idle... bigger is not always better when trying to choose a cam...

I would run a smaller cam with that set-up if it were me...
 
Okay thanks a lot for your reply. I am wondering why u say I will need rhoades lifters and not use the lifters that come in this kit?
 
Brayden Holden said:
What sort of cam would you recommend me running also mate? Very confusing trying to pick a cam
Click to expand...

I know someone who had that cam in a 340. I heard it run and it seemed to be more showoff of lumpy idle than low end power. He didn't like the cam after installed. I would look into a Comp XE cam like the XE268 or XE262. I prefer the XE268.
Good luck with your choice.
 
When I kind of explain the cam to people I tend to call it the conductor. It's conducting everything when and where and how to do it. Of course I went absolutely Bonkers with my cam and went to the moon in the top. I'm ready to switch it out for something a little less radical. Another place for you to look is Hughes. They have what's called a whiplash Cam that does kind of the same thing. But also know that they just resale cams they don't actually grind them themselves. I myself used Oregon cam Grinders and talk to Ken. A place like that has a professional has used all the cams and grinds them himself and races with them himself. Sometimes just not buying one off the shelf and asking professional cam Builder questions like these might benefit you? I'm sure some people can give you some other people that do this and you'll find them to be less expensive and custom made to your needs. Just another option for you. Generally a cam selection is extremely hard. But maybe sometimes as these cars are a bit of a hobby a lot of times you all pick a cam and learn something from it. Like I did. the next time you have experience.
 
Rusty has a nice Crane Cam for sale in the for sale ads. That and a set of the Rhoades lifters, matching springs.
Or an 268 xtreme. Not a thumper. My $.02
 
I have not ran a thumper or a xe268.
There are many who say the thumpers don't work ?
However someone car craft , or hot rod , I can't remeber ?
Well they had a dyno handy and the thumper actually made more power then the other cams ?
I'm sure you could look it up .
Best of luck !!
 
The factory LRE 360 had a 340 speed camshaft from factory and worked very well, when I first rebuilt the engine years ago I added the Aluminum LD340 intake, headers and used the mopar performance 268* .450 .455 camshaft and was happy with its performance (like Jpar first I tried the MP .508 cuz I thought bigger was better - it was lopey but that was it...)
 
lil red said:
The factory LRE 360 had a 340 speed camshaft from factory and worked very well, when I first rebuilt the engine years ago I added the Aluminum LD340 intake, headers and used the mopar performance 268* .450 .455 camshaft and was happy with its performance (like Jpar first I tried the MP .508 cuz I thought bigger was better - it was lopey but that was it...)
Click to expand...
Yes I'm a little over 600 lift right now LOL with about five on the lobes separation LOL
It's great for the drag strip! But I want to drive it on the street a little more...
 
Brayden Holden said:
Okay thanks a lot for your reply. I am wondering why u say I will need rhoades lifters and not use the lifters that come in this kit?
Click to expand...

Because Rhoades are variable duration and bleed down below 3500 RPM to take out about .025" of lift and 15° of duration to make the cam run smoother at idle... They increase idle vacuum and low and mid range without sacrificing mid range and top end... It's like having an adjustable cam almost and you get to have your cake and eat it too... I've been using them for over 30 years on daily drivers and put over 200,000 miles on engines with them.. They still work even with high pressure high volume oil pumps...

I installed a MP 484/284 cam in my Barracuda and with standard lifters, it wouldn' idle below 1100 RPM with 11" HG at idle... I then installed Rhoades lifters in that engine and was able to get it to idle at 800 RPM with 13" - 14" hg vacuum....

I put a stock 340 cam in a 318 with rhoades lifters and with 318 heads, it idled at 24" Hg vacuum... Then swapped the 318 heads with a set of 360 heads and it idled at 22.5" hg Vacuum... I got 17.75 MPG out of it with a 2.76 gear on a daily driver...

The higher the vacuum, the more velocity in the port... As a great head porter that I talked to once said, "velocity is torque"....

Here's the main page for them:

Rhoads Lifters

Here's the articles to describe how they work, the second one is the better one to read, but I would recommend reading both:

Articles

Don't go with knock offs, if you want to run variable duration lifters, go with Rhoades...
 
Brayden Holden said:
What sort of cam would you recommend me running also mate? Very confusing trying to pick a cam
Click to expand...

The stock 360 with flat top pistons will be around 8:1 compression and will want a more mild cam than the one that you picked... Too much overlap will lower your cylinder pressures and you don't have much compression to compensate...

I would run in the 270° - 285° duration range with that engine... And use Rhoades lifters...

Also keep in mind to look at cam overlap (where both intake and exhaust valves are open at the same time on the same cylinder) and lobe separation (how far apart the intake lobe center line is to the exhaust center line)... Lobe separatiion determines overlap... Most cam manufacturers will list lobe separation and not give overlap...

The cam that you picked has a 107° lobe separation... You can get some cams with a 110° - 114° lobe separation which will have less overlap and will give more cylinder pressure... Overlap bleeds cylinder pressure... The lower the number for lobe separation, the higher the overlap... The higher the lobe separation, the less overlap and smoother idle and higher cylinder pressure you will have... You will loose that rough lumpy idle that you are desiring, but your car will run better and faster with the lower overlap with the compression that you will have on that 360...
 
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I think you have heads 3418915 - 1970 - 1972 340 and 360 heads. Compresion ratio too low for that cam , maybe go taller pistons or smaller head chambers. What rear gear, vehicle weight , and ****?
 
Sorry if i missed it, but what is around the motor? Gears, tranny/converter, headers or manifolds, weight of car...... Higher gears, 4 speeds or good aftermarket converter, and light cars allow for the use of more cam (more lift/duration). But without knowing any of it, I'd say keep the lift between .444 - .474, duration between 212-224* @ .050. If you are running factory manifolds, I'd run a split pattern cam.

I'm running even less cam in one of my 360's. I think it's .427/.444 lift and .204* on intake @ 050. But I have factory manifolds, stock converter with 2.45 gears.
 
Brayden Holden said:
View attachment 1715159329 View attachment 1715159328 I and a 1978 360 chrysler with standard heads and flat top pistons etc, I need to replace the cam shaft, I have been doing some browsing on the net. I am wanting to try make it lumpy. I like the look of this package ...

COMP Cams Thumpr Hydraulic Flat Tappet Cam and Lifter Kits K20-600-4

Will this be alright in my engine? Or will this require some work to the heads? Or will it all work fine?

Thanks in advance for anyone’s input that can help me as at the moment I am not wanting to buy different heads.

I have put in a photo of my block engine number and head number
Click to expand...

Choosing a camshaft can be difficult.
What we need to know is what gear ratio and tire size you have in your car or what will be used. Also, knowing th intended useage of the car is a huge help. Also, are you willing to change out the torque converter for a higher stall unit?

IF you just want to add a cam and 4 bbl. carb to the engine for a mild pick me up, here is my suggestion;

COMP Cams High Energy Cam and Lifter Kits K20-210-2
 
Thanks everyone for reply’s it’s going in a 1976 vj valiant sedan, I am more after noise than performance with this engine,
 
with a 107 lsa your compression might be to high for reg gas I would check your compression before ordering a cam , is it a stock bottom end low comp pistons
 
A lumpy idle and low-compression is a recipe for disappointment, every time you put it into gear, thay nothing will cure except a high stall TC; in your case a higher than appropriate stall for street.
But you could cheat with a cam that has a similar IVC to stock,but withe LSA tightened up.
 
IIRC the factory 360 2bbl cam is a 252/260/112. In at 108 the ICA is 54*, and this with an 8.0, 360 will get you a Dcr of about 6.9@132psi and a VP of 120 ..This is about as low a pressure as you wanna run. And the overlap would be 32 Degrees.

Well, you could grab a Comp 262/270 cam and have those lobes put on with a 104LSA. and install it with the same ICA of 54 degrees, to get overlap of 58*; not up to the Thumpr's 73.5, and not nearly as lumpy....... but your compression and power events won't change much.
But you will have more specific power, at about 300/400 rpm higher and not suffer the driveability issues.So your gonna need new springs.
IMO, this is a reasonable solution, if you are just after the sound.
That 279/296/107 Thumpr cam will reduce your low-rpm performance about 12%. Just to get back to where you are at, you will have to rev the engine higher to find 12% more power. That means a New TC and more money
With the 262/104 cam, you could leave the combo alone. And the fuel mileage at steady-state will not change much either. Whereas that Thumpr will suck gas big-time.
 
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Yes. The whiplash cams from hughes actually work pretty well. I put a thumper cam in a friends 8.75 to 1 360 and it sounded good but the power wasn't impressive. Rode in a car with 8.2 to 1 comp. 360 with the bigger whiplash cam and it ran very strong for what it was.
 
aaronk785 said:
Yes. The whiplash cams from hughes actually work pretty well. I put a thumper cam in a friends 8.75 to 1 360 and it sounded good but the power wasn't impressive. Rode in a car with 8.2 to 1 comp. 360 with the bigger whiplash cam and it ran very strong for what it was.
Click to expand...

Thumper cams suck. Wrong cams suck also. J.Rob
 
OP has those mysterious mid late 70's 915 heads short the "1" of the original 340/360 head casting. 348915 instead of 3418915

Just keeping track of them. Lol
 
hughes whiplash works better than the thump
however both are really for under 9:1
change your mufflers
both have way too much exhaust duration especially if running headers
see those who are having ex valve problems
there are better choices for almost every case
except maybe yours if low compression
 
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