Low compression 360 cam suggestions
- Thread starter petethekiller
- Start date
-
Richard's 360 Van engine (above) and 318willrun's 360 Duster etc.. should be enough evidence alone for AJ to at least give him some pause and rethink his statements for there accuracy about how mods will effect a low cr engines hp and torque.
Below examples of other Mopar displacements built on low cr still making decent hp and torque.
Here's the effect of 4bbl headers and xe262h cam on a low cr 318
https://www.hotrod.com/articles/mopp-0312-318-long-block-bolt-ons/
Here's a low cr 440 build.
Dyno testing a stock(?) 1972 440
"But what can it achieve on a low compression 440? With the 516's we are now all the way up to 7.85:1 compression, woo-hoo!"
RPM..............TQ............HP
3000.............434..........248 my test, I'll start the RPM where I want.
3100.............445..........263
3200.............457..........278
3300.............458..........288
3400.............462..........299
3500.............458..........305
3600.............447..........307
3700.............443..........312
3800.............443..........321
3900.............446..........331
4000.............450..........343
4100.............453..........354
4200.............461..........368
4300.............463..........379
4400.............461..........386
4500.............470..........402 402 HP? hang on!
4600.............473..........414 peak torque? really, there is a peak? maybe a plateau.....
4700.............468..........418
4800.............467..........427
4900.............459..........428
5000.............459..........437
5100.............453..........439
5200.............453..........448 1 HP/CI
5300.............445..........449 Peak HP
5400.............428..........440
5500.............421..........441
5600.............407..........434
5700.............397..........431
5800.............391..........431
Below examples of other Mopar displacements built on low cr still making decent hp and torque.
Here's the effect of 4bbl headers and xe262h cam on a low cr 318
https://www.hotrod.com/articles/mopp-0312-318-long-block-bolt-ons/
| TORQUE SUPERFLOW 901 DYNO-TESTED AT WESTECH | |||
| RPM | BASE | MOD 1 | MOD 2 |
| 2,000 | 292 | ||
| 2,500 | 287 | ||
| 3,000 | 287 | 338 | 336 |
| 3,500 | 272 | 335 | 340 |
| 4,000 | 248 | 326 | 330 |
| 4500 | 218 | 309 | 319 |
| 5,000 | 188 | 285 | 296 |
| 5,500 | 250 | 258 |
| HORSEPOWER SUPERFLOW 901 DYNO-TESTED AT WESTECH | |||
| RPM | BASE | MOD 1 | MOD 2 |
| 2,000 | 112 | ||
| 2,500 | 137 | ||
| 3,000 | 164 | 193 | 192 |
| 3,500 | 182 | 224 | 227 |
| 4,000 | 189 | 248 | 252 |
| 4,500 | 186 | 265 | 274 |
| 5,000 | 179 | 271 | 282 |
| 5,500 | 262 | 270 |
Here's a low cr 440 build.
Dyno testing a stock(?) 1972 440
"But what can it achieve on a low compression 440? With the 516's we are now all the way up to 7.85:1 compression, woo-hoo!"
RPM..............TQ............HP
3000.............434..........248 my test, I'll start the RPM where I want.
3100.............445..........263
3200.............457..........278
3300.............458..........288
3400.............462..........299
3500.............458..........305
3600.............447..........307
3700.............443..........312
3800.............443..........321
3900.............446..........331
4000.............450..........343
4100.............453..........354
4200.............461..........368
4300.............463..........379
4400.............461..........386
4500.............470..........402 402 HP? hang on!
4600.............473..........414 peak torque? really, there is a peak? maybe a plateau.....
4700.............468..........418
4800.............467..........427
4900.............459..........428
5000.............459..........437
5100.............453..........439
5200.............453..........448 1 HP/CI
5300.............445..........449 Peak HP
5400.............428..........440
5500.............421..........441
5600.............407..........434
5700.............397..........431
5800.............391..........431
Typical.
Yet somehow people will argue the same HP from a higher compression engine is somehow "better". LOL
IQ and Holdener testing blow the camshaft is too big thesis out the window. It's about filling the cylinder, compressing it and making it go bang! Don't forget wanting a choppy idle. Get something cut on a 106-108 for a little more overlap if you want chop at idle.
More torque is going to make the converter stall higher as well. 50 extra pounds and the alleged "lack of" is a moot point. Converter stalls 200-300 higher, already really close or in that stall range.
I'm just a dummy that liked to put 484 cams with a 108 LSA in at 100 in those dog *** low compression 340's and truck motor LC 360's...
They ran pretty good too, better than if I put a stock 340 or smaller cam in them. We were just dumb kids from the late 70's into the 80's on a budget with marshmellow torque converters available.
More torque is going to make the converter stall higher as well. 50 extra pounds and the alleged "lack of" is a moot point. Converter stalls 200-300 higher, already really close or in that stall range.
I'm just a dummy that liked to put 484 cams with a 108 LSA in at 100 in those dog *** low compression 340's and truck motor LC 360's...
They ran pretty good too, better than if I put a stock 340 or smaller cam in them. We were just dumb kids from the late 70's into the 80's on a budget with marshmellow torque converters available.100%, even if it did, not like most of us are in a highly competitive race class, it's ok to be a little slower than it could be as long as the mods are overall improvements and or the OP's are happy with it, I bet most just want a lumpy burnout machine.
I think the smog era probably has a lot to do with it, many seem to associate the death of the Muscle car with smog engines being low cr as one of the main factors. Net power ratings are probably more to blame because at the same time cr was dropped engines went from gross to net seeming to make the lost even worse.
Is a 8:1 better than a 10:1 of course not, but same can be said about many things headers vs manifolds, 2bbl vs 4bbl, different heads, cam etc.. many ways to leave power on the table. If not rebuilding the engine cr is kind of a hard thing for most to change, shouldn't be a reason not to hop up an engine. Don't see how AJ figures a stock cam and 2bbl gonna smoke a 4bbl and decent cam probably a 50 hp + upgrade at peak and decent increase across the curve should be a night and day difference no matter what the V/P and or cranking psi says.
That's a great point, and really how long does and engine stay under 3000 rpms at full throttle anyways even with highway gears and stock stall. Obviously stall gears and cr gonna make things better but those are the 3 things people seem least likely to change or last on a lot of peoples list, doesn't mean they still can't benefit from a basic hop up, cam, 4bbl, exhaust and a tune.
petethekiller
Well-Known Member
Some quick answers to a few questions:
The Truck: 1975 D100 Long bed 2WD... I will guess 3650lbs on the high side.
3.55 gears with 28 inch tire
Again, the 360 short block is an off the shelf reman 1978 360: Top end with consist of speedmaster heads that have been milled to 64cc and gasket matched. With Eddy Air Gap intake and probably a 650DP brawler. Headers and the Typical bolt on parts. I am pretty much sold on the XE268 Cam. I hope to make similar numbers as in Richards video.
The Truck: 1975 D100 Long bed 2WD... I will guess 3650lbs on the high side.
3.55 gears with 28 inch tire
Again, the 360 short block is an off the shelf reman 1978 360: Top end with consist of speedmaster heads that have been milled to 64cc and gasket matched. With Eddy Air Gap intake and probably a 650DP brawler. Headers and the Typical bolt on parts. I am pretty much sold on the XE268 Cam. I hope to make similar numbers as in Richards video.
PRH
Well-Known Member
My “fwiw”……..
“If it were me” I’d use either the XE256 or XE262…….in that vehicle.
“If it were me” I’d use either the XE256 or XE262…….in that vehicle.
I have a 360 on the stand with a XE262 in it going into an Aspen R/T. Good cam for an all around driver deal.
If a 702 voodoo cam can be found, another good choice. 265/271 220/226 @ .050 .475/.494 112lsa 108ICL
Going to get a bit of a boost in static compression going to the alum head.
That graph that Holdener has isn't likely going from a deficit where the low rpm pull starts to +50 in that short of a range. Probably going to above it from bottom to top.
Last edited:
I have to say, that is a nice looking truck! I love that color!
The XE268 should be a nice cam in that.
This video came up on my youtube suggestions thought it would fit here.
They weren't happy with 9.1:1 cr (140 cranking psi) results with the cam they had so they bump it up to 9.88:1 and advanced the cam (170 cranking psi). The results (At 4:22) average gains at peaks 9 hp and 16 lbs-ft it's an ok gain but not the end of the world at the original 9.1:1/140 psi.
They weren't happy with 9.1:1 cr (140 cranking psi) results with the cam they had so they bump it up to 9.88:1 and advanced the cam (170 cranking psi). The results (At 4:22) average gains at peaks 9 hp and 16 lbs-ft it's an ok gain but not the end of the world at the original 9.1:1/140 psi.
I think that's a little big, but go for it.
Yeah. Talk about not enough gains for all that work. You can preach it all day long, but people just won't listen.
-
Similar threads
- Locked
