PRH
Well-Known Member
Luv it!!!
Pick a cam for me
- Thread starter ike61
- Start date
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Luv it!!!
That’s the way it was before the internet! That’s the way I learned. Purchase the part, install the part, test the part, record the results and compare. Make a call from there on the next experiment.
It is called “Tuition.”
Read lots of books, talked to a lot of people, tested many parts. I loved doing it. For me, this is where the fun is at.
Johnny Dart
Well-Known Member
Nobody ever mentioned the Mopar "Purple Shaft" 450/455 cam. This cam was recommended to me by close friend
Hemi George. The guy is a Mopar veterain, and swares by this cam in a 340/360. This is a 340 that I put together for a buddy of mine, with the 450/455 cam. He has broken the cam in, but still needs to finish the rest of the car. Anxious to see how it runs.
Hemi George. The guy is a Mopar veterain, and swares by this cam in a 340/360. This is a 340 that I put together for a buddy of mine, with the 450/455 cam. He has broken the cam in, but still needs to finish the rest of the car. Anxious to see how it runs.
PRH
Well-Known Member
Its certainly a viable option.
I like that cam. Lift is a bit low so the valve job has to be good and helpful. The duration is IIRC 230@050, excellent street machine cam. Not to big, not to small.
The problem is here at s that there are so many cams that fit into this category that will all perform well.
The problem is here at s that there are so many cams that fit into this category that will all perform well.
Wyrmrider
Well-Known Member
For those that want a cam that lasts and has more power than a similar duration white box cam the MP cam is an excellent choice
There's those that just work, those that perform, and those that perform better
added some intake close points for those doing dynamic compression
an update to include the 240 comp
240 192@.050 not much intake closes 50 ABDC w/108LCA stock low compression 318 with tall gears and heavy vehicle
250 126 .454 52ABDC w/110LCA 108ICL
252 126 .481 52ABDC
255 128 .478
256 130 .454 55ABDC 9:1
256 tbd .461
257 130 .483 56ABDC
261 134 .494 9.5:1
262 138 .475
263 136 .498
265 138 .502 9.7:1
267 140 .506
268 145 .494 60ABDC 10:1
269 115 .430 MP 260
to answer a previous question
"see how much more duration you have to run to get the same area and how much DCR you loose 's not about top end hp- just spinning it faster can hide that"
To get as much area from a universal lifter cam as you have from a Mopar 255 cam takes at least two sizes. 262 dosen't cut it It takes a 268
or 12 degrees or say 6 degrees more intake close
advancing the old school cam 4 degrees does not restore the dynamic compression
and to answer one of the questions above which is realated to this
more lift can cost power if you get turbulent in the port
but it' usually more duration that is opening the intake early and diluting the charge with reversion. You can get away with it with a race motor because it will clear up with revs- but no fun on the street
and advancing a cam to what is 8 degrees with the built in 4 hurts reversion and also the power stroke by opening the exhaust early
No free lunch
There's those that just work, those that perform, and those that perform better
added some intake close points for those doing dynamic compression
an update to include the 240 comp
240 192@.050 not much intake closes 50 ABDC w/108LCA stock low compression 318 with tall gears and heavy vehicle
250 126 .454 52ABDC w/110LCA 108ICL
252 126 .481 52ABDC
255 128 .478
256 130 .454 55ABDC 9:1
256 tbd .461
257 130 .483 56ABDC
261 134 .494 9.5:1
262 138 .475
263 136 .498
265 138 .502 9.7:1
267 140 .506
268 145 .494 60ABDC 10:1
269 115 .430 MP 260
to answer a previous question
"see how much more duration you have to run to get the same area and how much DCR you loose 's not about top end hp- just spinning it faster can hide that"
To get as much area from a universal lifter cam as you have from a Mopar 255 cam takes at least two sizes. 262 dosen't cut it It takes a 268
or 12 degrees or say 6 degrees more intake close
advancing the old school cam 4 degrees does not restore the dynamic compression
and to answer one of the questions above which is realated to this
more lift can cost power if you get turbulent in the port
but it' usually more duration that is opening the intake early and diluting the charge with reversion. You can get away with it with a race motor because it will clear up with revs- but no fun on the street
and advancing a cam to what is 8 degrees with the built in 4 hurts reversion and also the power stroke by opening the exhaust early
No free lunch
Last edited:
PRH
Well-Known Member
You’ll have that once in a while.
A little “TMI”
Still got to 4 pages though ;)
A little “TMI”
Still got to 4 pages though ;)
Johnny Dart
Well-Known Member
Think we scared the OP, he never reposted after his original question
Lol
Happens all the time.
Last I heard, he bought a Chevy.
He was here in the morning
MOPAROFFICIAL
If it has tits, it's a liabilititty.
Cam?
Pfft... crate motor.
Pfft... crate motor.
I really like the MP grind, too. I’m hoping the OP has been busy changing out and lets us know what he went with. Johnny Dart’s recommendation reminded me of another cam I've had experience with and would also play nicely with the wide step overdrive 4 speed. I’ve seen The Comp XE 262H work very well in heavy trucks with a wide ratio heavy duty four speed. I would have thought the 268 to be a little on the large side, but I’m not going to argue with results!
Wyrmrider
Well-Known Member
thanks garrett
even with a low compression heavy truck you want the torque where you are driving rpm
lower gears require a much bigger cam than a 2.74 gear and tight converter
a realwork truck
so you do not have to shift down as much
We did do a lot of dyno work on 360 motorhome motors and 440 Transit bus motors
on the transit busses we went shorter to a 192@ .050 430 lift cam from Bill Jenks at Moon/ Potvin cams
an upgrade to the 361-413 truck cam the busses had a very wide trans with a big rpm drop
The 360 motor homes were TF with highway gears not truck gears big difference
even with a low compression heavy truck you want the torque where you are driving rpm
lower gears require a much bigger cam than a 2.74 gear and tight converter
a realwork truck
so you do not have to shift down as much
We did do a lot of dyno work on 360 motorhome motors and 440 Transit bus motors
on the transit busses we went shorter to a 192@ .050 430 lift cam from Bill Jenks at Moon/ Potvin cams
an upgrade to the 361-413 truck cam the busses had a very wide trans with a big rpm drop
The 360 motor homes were TF with highway gears not truck gears big difference
So what have you decided on???
hotrod swinger
Well-Known Member
I’m very happy with compcams 20-670-4:
Nostalgia Plus 233/240 Hydraulic Flat Cam for Chrysler 273-360
Nostalgia Plus 233/240 Hydraulic Flat Cam for Chrysler 273-360
hotrod swinger
Well-Known Member
Lol, sorry just realized this thread is over a year old.
IMO! Your added opinion is still worthy.
I don’t let guys who go 4 pages into a thread and then crickets off the hook!
These Threads are forever
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