CAM PERFORMANCE QUESTION

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clementine

clementine

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As I get closer to starting this engine for the first time (for me) I wonder how this cam is going to act. I got the engine with the car 7 years ago and promptly lost the cam card so this is completely off of memory, so I apologize in advance, but I wonder what you guys think. I called the engine assembler/builder in the early years of ownership and remember him telling me that he remembers doing a fairly stock setup on this motor ie cast pistons with around a 9:5:1 compression ratio. This is a 383 B motor. I can get the casting #s off the heads tonight if it makes a big difference. This is the cam.

CHRYSLER COMP Cams 21-248-4 COMP Cams Magnum Solid Camshafts | Summit Racing

Thanks FABO!
 
That seems like a pretty big cam for a 383; but maybe it will work with the rest of your combination. I think others here, have used some that are similar, with good results.
 
Yeah, I thought it might be a bit big. I remembered the specs were on a summit sheet and I remember flat tappet, 250/250@50. Im pretty sure thas whats in it. Its a 67 barracuda FB with 3:91s, an A833 non OD and a 28" tall tire.
 
It's a lot of cam, but a good hot, loose ignition curve will make it run very well.
 
Plymouth 65 said:
Seems like alot of cam for the compression ratio you have. 65'
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Well, I am just gonna send it at this point. I have so much other stuff to get done, and it needs to run soon. For my own sanity. Ill shove some headlights in it and a windshield at this point to see what its gonna do.
 
RustyRatRod said:
It's a lot of cam, but a good hot, loose ignition curve will make it run very well.
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Im running the hyper spark with a holley efi. Not sure how to set up many of the things I read about on here, including hot loose curves....but I met a girl once that fit that description.:lol:
 
clementine said:
Im running the hyper spark with a holley efi. Not sure how to set up many of the things I read about on here, including hot loose curves....but I met a girl once that fit that description.
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I believe you can tune it to run very well. Millions of "overcammed" engines have performed extremely well. Yours will too.
 
clementine said:
Well, I am just gonna send it at this point. I have so much other stuff to get done, and it needs to run soon. For my own sanity. Ill shove some headlights in it and a windshield at this point to see what its gonna do.
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I would. I think it will be fine.
 
I ran the small block version in a 11-1 360. Nice snooty idle and good power. Seen this in a Duster running 11’s.
Comp ratio may be a bit low but that’s also OK with the 4spd and 3.91’s. Give a 150 shot and call it good, because it will be.
 
clementine said:
I am going to get a coil in the near future. I have the bracket and wiring set up for a regular coil. Is there a "hot" coil to compliment the "loose curve" that I should keep an eye out for?
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When I said hot, I was referring to the curve. Most any coil will work fine. It's a fairly low compression engine as coils go. I wouldn't worry about a fancy coil until you really started getting some cylinder pressure. 9.5 with that cam won't be pushing it. It won't be a dog either. I'd "guess" maybe 140 PSI cranking pressure. Maybe. But I just shoot from the hip, I don't have calculators and slide rules up my ***.
 
Thanks fellas. Ill do a separate post when I get her started. with a vid n stuff.

Is there a certain temp of plug I should start with?
 
clementine said:
Thanks fellas. Ill do a separate post when I get her started. with a vid n stuff.

Is there a certain temp of plug I should start with?
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Yup. I'd go with the stock heat range and "whatever" brand you like.
 
It's going to be a little peaky, strong mid-range and upper end. But with a good tune and all things working properly it should run very well in my opinion. It's going to be thirsty and sound great. It'll would respond well to having the cam advanced 4 degrees. Both helpful to the compression ratio and moving the RPM range down a little bit, it would be a must for me.
 
Thanks! good info here! Im hoping to get her started soon! total re-wire, car came in boxes, obviously didnt build the motor myself, but have done everything else. It would be nice to be able to put the 325/50R15s to work!
 
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K.O. SWINGER said:
It'll would respond well to having the cam advanced 4 degrees. Both helpful to the compression ratio and moving the RPM range down a little bit, it would be a must for me.
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Good idea. Double check piston to valve clearance. You should still have plenty, but check to be sure.
 
Since it’s already in the motor, you might as well try it.

That being said, it’s not at all what I would have suggested for a 383 with an OD trans and EFI.

You’ll either like it...... or you won’t.
 
PRH said:
OD trans
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NON OD. I should have just put A833, but I thought I would specify....best laid plans.
Agreed, after reading many 'cam choice' threads on here, I have not seen many 'square' ish cam choices. I still am wrapping my head around cam science, especially overlap and centerline. But as you said....its in....run it. Im sure after initial shakedown, this car will come apart again. But it will go back together much quicker. I am trying to build it thinking to myself....'does this come apart and go back together easily and quickly?'
 
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