Cam duration question

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Dartvader440gt

Dartvader440gt

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My Dart restoration is coming along great. Getting ready to do some assembly finally. Now I bought this car way back in 2003. We are going through the 440. We are pulling the cam and going to install new cam and lifters.
The cam coming out is the
B/RB 361-440, 284/484 Hyd Flat Tappet

.484" / .484" Lift. 241/241 Duration @ .050" 108 + 0 L/C

One Bolt Pattern

Street / Strip

The one I can get from Mancini racing is
B/RB 361-440, 284/484 Hyd Flat Tappet

.484" / .484" Lift. 239/239 Duration @ .050" 108 + 0 L/C

One Bolt Pattern

Street / Strip

Is there a big difference in the duration going from 241 down to 239?
 
Dartvader440gt said:
My Dart restoration is coming along great. Getting ready to do some assembly finally. Now I bought this car way back in 2003. We are going through the 440. We are pulling the cam and going to install new cam and lifters.
The cam coming out is the
B/RB 361-440, 284/484 Hyd Flat Tappet

.484" / .484" Lift. 241/241 Duration @ .050" 108 + 0 L/C

One Bolt Pattern

Street / Strip

The one I can get from Mancini racing is
B/RB 361-440, 284/484 Hyd Flat Tappet

.484" / .484" Lift. 239/239 Duration @ .050" 108 + 0 L/C

One Bolt Pattern

Street / Strip

Is there a big difference in the duration going from 241 down to 239?
Click to expand...
3 degrees.
 
Not at 0.050" probably similar depending how fast the ramps are if there a lift at .200" spec would tell you more but doubt there's much of a difference.
 
That cam is going to have a lumpy idle, low idle vacuum. Carb & ign timing will have to be 'tuned' to work with it. If you are just building a cruiser, there are better cams to choose from.

Read this warning from Erson cams:

img282.jpg
 
If that’s what you want, you’ll be fine.

The original 284 didn’t measure 241 at 0.050”.
 
My last 2 engine builds, I called the cam company I went with, and tol them about my combo, and what I was going to do with it. They then provided a cusotm grind for my appication. THEN, I called a converter company and gave them combo and cam specs, and had a custom converter made for my application.
 
Dartvader440gt said:
What are the issues? I'm unaware of this? And if so, what the mechanical equivalent?
Click to expand...
The lifters leak down after sitting just for a day or two. The engine will have bad tick from this on start up. It does go away after a while of running but but usually do it every time you start it. Ran in to this on several builds. Tried changing lifters but the new replacements do the same . This is on several different engines not specific to mopar. Yes we tried the preload from zero lash to 1/2 the plunger travel.

Also the mopar hyd. 474 and 484 cams don't have a wide torque range. They sound awesome but that is it. Same as a "mother thumper " from Comp. Built for sound. Most of the Mopar performance cams you'll need at least a 3500-4500 torque converter or you won't even be able to spin one studded snow on ice.

I cannot give you a specific cam to use . Your engine builder should choose that after compression ratio is determined and head choice. The best cam I ever used on the street with the most torque for a street car was a 465 lift 302 duration. It was an oval track cam. The engine had 10.5 compression a stock 70 340, 915 J 202 heads. LD 340 intake 750 4 corner holley style carb. A bone stock 340 with bigger cam and an Edelbrock intake. Stock 3200 converter and 355's.
 
To answer your question, no, it won't make ay notable difference.

I wouldn't run that cam if it were me. Why, because I have run it.. unhappily. As mentioned, I too would run a solid cam. I'd want a cam that opens the valves! Minimum .500 lift. The 108 LSA is ok, I prefer a wider LSA in most cases for a plethora of reasons. The cam I ran in lieu of yours was [email protected], .528 lift, 112lsa. That cam made 467hp@5600RPM, 514ft@3900RPM and went 11.70's @114 and you could drive it anywhere.
 
Last edited:
BSB67 said:
Yep. The MP 528 does everything better than the 284/484.

Folks just don’t like solids.
Click to expand...

And the only reason why is lack of knowledge

People think they need to adjust them all the time, and don't know how to do it. I haven't adjusted mine in 2 years. Once a year max.
 
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