|
Re: Is a Purple cam, standard bore, 340power brake friendly
[Re: ahy]
#1244945
06/04/12 10:18 AM
06/04/12 10:18 AM
|
Joined: May 2008
Posts: 958
eastern, pa.
cudabitten
OP
super stock
|
OP
super stock
Joined: May 2008
Posts: 958
eastern, pa.
|
Quote:
Quote:
the 284-484 wont make enough vacuum for power brakes. Its 248* @.050" and ground on a tight 108 lsa.
Agree... much over 230 to 235@ .050 in a 340, especially with tight LSA, isn't going to make enough vacuum for PB.
One member mentioned a lower duration purple shaft that would likley work, there are other options. What are your goals?
My goal is to have a street friendly 340, that has enough power to be fun. Also I want to keep my power brakes and get the 904 rebuilt with a shift kit. I was thinking something like the transco TF6 Automatic shift kit.
This is my first restore, and I'm trying to keep costs down and use what I have. The car came with a 318, but the cost to rebuild it are about the same as buying a rebuilt 340, so I might as well get the engine I always wanted.
|
|
|
Re: Is a Purple cam, standard bore, 340power brake friendly
[Re: AdamR]
#1244947
06/04/12 02:07 PM
06/04/12 02:07 PM
|
Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,376
|
There is NOTHING MAGICAL about the "purple cam". It is purely advertising hype. Those MP cams are at least 30 years old. Even smallblock chevies have more lift per duration than those cams do, and the chevy lifter diameter limits lifter acceleration compared to the Mopar lifter diameter.
I'd suggest a phone call to Lunati and have them pick out a cam from their Voodoo line. Or Call Hughes and ask them. I'd suggest something around 220 degree intake and 226 degrees exhaust on a 110 LSA run advanced 4 degrees.
R.
Last edited by dogdays; 06/04/12 02:09 PM.
|
|
|
Re: Is a Purple cam, standard bore, 340power brake friendly
[Re: RSNOMO]
#1244949
06/04/12 06:52 PM
06/04/12 06:52 PM
|
Joined: Sep 2005
Posts: 406
California City, CA
dart440
mopar
|
mopar
Joined: Sep 2005
Posts: 406
California City, CA
|
Ran the 284/484 cam in my 70 Chally convertible 4-speed with an otherwise stock 340, had NO assist at idle/low speed. Went with Rhoads lifters and then I had power assist. The thing idled really lopey and ran hard. Loved it except for the low vacuum for the brakes. I would not recommend the cam unless you are going to run a vacuum reservoir or electric vacuum pump for the brakes. Of course this engine was built in 1984 so the cam may be different now as someone suggested.
When you work on Spaceships for a living, how bad can a workday be?
|
|
|
Re: Is a Purple cam, standard bore, 340power brake friendly
[Re: dogdays]
#1244950
06/05/12 11:37 PM
06/05/12 11:37 PM
|
Joined: Mar 2005
Posts: 3,445
N.Wilkesboro,NC
DusterKrazy
master
|
master
Joined: Mar 2005
Posts: 3,445
N.Wilkesboro,NC
|
Quote:
There is NOTHING MAGICAL about the "purple cam". It is purely advertising hype. Those MP cams are at least 30 years old. Even smallblock chevies have more lift per duration than those cams do, and the chevy lifter diameter limits lifter acceleration compared to the Mopar lifter diameter.
I'd suggest a phone call to Lunati and have them pick out a cam from their Voodoo line. Or Call Hughes and ask them. I'd suggest something around 220 degree intake and 226 degrees exhaust on a 110 LSA run advanced 4 degrees.
R.
Well...it is old technology but I don't care because they work well in all my applications.
|
|
|
Re: Is a Purple cam, standard bore, 340power brake friendly
[Re: DusterKrazy]
#1244951
06/06/12 01:46 PM
06/06/12 01:46 PM
|
Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,376
|
Whatever...It's your money.
But if you think you aren't leaving horsepower or driveability on the table you are mistaken. A few years ago one of the writers who normally write about Mopars, I think it was Steve Dulcich, did a test where he used "chevy lobe" cams and then similar duration cams optimized for the Mopar lifter diameter. He found definite horsepower gains from the quicker accelerating lobes. For example, Hughes hydraulic cams will get the same lift as an MP camshaft with 20 degrees less duration at 50 lift.
I maintain that there must have been wizards at ChryslerCorp to come up with meaningless terms and then sell them as some sort of magic. I mean "purple shaft", Wedge head (every smallblock chevy from Day One has had a similar combustion chamber), Sure Grip (this name was applied to at least three different limited slips) and the like.
Also consider modern hydraulic roller cam pushrod engines going one horsepower per cubic inch with cams less than 216 degrees at 50. Slam the valve open, hold it there for as long as you can and then slam it shut. That's the ticket.
Now, if one had a dyno and some time, it might be possible to find an MP cam that outperformed those modern cams. For example, AndyF found that the .528 cam was unbeatable in his 451 stroker running stock exhaust manifolds. But that's after countless dyno pulls.
R.
Last edited by dogdays; 06/06/12 01:54 PM.
|
|
|
Re: Is a Purple cam, standard bore, 340power brake friendly
[Re: dogdays]
#1244952
06/06/12 11:52 PM
06/06/12 11:52 PM
|
Joined: Mar 2005
Posts: 3,445
N.Wilkesboro,NC
DusterKrazy
master
|
master
Joined: Mar 2005
Posts: 3,445
N.Wilkesboro,NC
|
Quote:
Whatever...It's your money.
But if you think you aren't leaving horsepower or driveability on the table you are mistaken. A few years ago one of the writers who normally write about Mopars, I think it was Steve Dulcich, did a test where he used "chevy lobe" cams and then similar duration cams optimized for the Mopar lifter diameter. He found definite horsepower gains from the quicker accelerating lobes. For example, Hughes hydraulic cams will get the same lift as an MP camshaft with 20 degrees less duration at 50 lift.
I maintain that there must have been wizards at ChryslerCorp to come up with meaningless terms and then sell them as some sort of magic. I mean "purple shaft", Wedge head (every smallblock chevy from Day One has had a similar combustion chamber), Sure Grip (this name was applied to at least three different limited slips) and the like.
Also consider modern hydraulic roller cam pushrod engines going one horsepower per cubic inch with cams less than 216 degrees at 50. Slam the valve open, hold it there for as long as you can and then slam it shut. That's the ticket.
Now, if one had a dyno and some time, it might be possible to find an MP cam that outperformed those modern cams. For example, AndyF found that the .528 cam was unbeatable in his 451 stroker running stock exhaust manifolds. But that's after countless dyno pulls.
R.
Aren't all these cars 40+ year old technology?? People use what they like and thats what makes the world go round. I hear people that think Comp cams are great but I don't like them at all.
The overall combination along with the cam and how it works with it is the real key.
We can just agree to disagree  
|
|
|
|
|
