Camshat/trans/gear combo 360

-
rtee007

rtee007

Deplorable Texan
Joined
Jun 10, 2014
Messages
376
Reaction score
21
Location
Baytown, Texas
Going to freshen up this 360 and the question here is the combo of:

Camshaft-P4120233AE
.508/.508 lift 292/292 duration 248/248 duration @ .050 centerline of 108 2200-6500 rpm Another camshaft option might be the P4120231AE: .484/.484 lift 284/284 duration 241/241 duration

Transmission-it is a 727 (no idea of the stall-but does have a trans brake)

Gear-Was told it is 4:56 SG and this appears to be true (spinning wheel and counting yoke rotations- a little short of 5)

The 360 has an Eddie Air Gap intake on it and a Eddie Competition Carb. I don't have funds to change the tall gear right now, but maybe next year I would reduce it to 4:10's, maybe some heads next year as well.

Appreciate any thoughts here, like to buy and get the camshaft installed and this engine wrapped up by next weekend.
 
Use the .508. It's got the gear for it.
 
Compression of the engine?

If it's lower, advance the snot out of the cam. Don't install it at 108, put it in at 100-102 with low compression. I've put them in as far ahead as 98. It will increase low end performance, especially if it's a street car.

Not a fan of your carb choice if it's a 600ish.
 
I do not know what the engine compression ratio is. So I will install at the recommended spec.

Carb is just what came on it, a Carter 625CFM. I have a few others around here to play with,


crackedback said:
Compression of the engine?

If it's lower, advance the snot out of the cam. Don't install it at 108, put it in at 100-102 with low compression. I've put them in as far ahead as 98. It will increase low end performance, especially if it's a street car.

Not a fan of your carb choice if it's a 600ish.
Click to expand...
 
I highly recommend that you dont buy a cam until you know the c/r.
-Then figure out the latest intake closing point to get your dynamic c/r to where it needs to be for your fuel and intended useage. Then figure out how much overlap youre willing to suffer with. Then add up the numbers to arrive at intake duration. Add 5 to 10 to that number to arrive at the exhaust duration.The smaller for headers, the larger for manifolds. This is called, back engineering. Now go shop for a cam that meets the numbers, with the fastest rate of lift you can find.Or get one built.
- You cant just poke a stick in there and hope for the best. Unless you are rich. Or have nothing but time.Or dont mind doing it over and over.Well I guess I should soften that statement;IMHO its best not to just poke any old stick in there and hope for the best.
-BTW, that 292/509 demands some decent compression. Like 11/1 or better, or it will be pretty soft below 2500. Which with your combo will work, I guess.But its a real trick to tune, for a streeter. I ran it on the street in a stick car with an 11:1 starter gear. I didnt like it much. When a young guy came along and heard my story, I sold it to him. Good riddance to that stick. Sorry. I didnt find it M/T friendly, nor street friendly.BUT; that was a wicked sounding cam at idle, and it pulled forever.I shifted at 7200, but that cam I think wasnt done yet.
-I love that Dart body style. And I really like the looks of yours.
-I bought a 70 Swinger 340 back in 70.Panther Pink stick. I loved that car. Didnt handle very good though.Got me into a lot of trouble.Ahh, the memories.
FWIW; that 292 cam will need; some honking big tires, tubs, springs, and axle-wrap control.It will get that Dart into trouble in a hurry, so budget big brakes, big T-bars, and a full suspension overhaul, and frame connectors. Also on the list are bigger fuel pump,deeper pan,a cooling system inspection/overhaul,a high power ignition system, and seat belts. Your car may already have most of this stuff on it, I dont know. I just see smallish tires and flattish springs with a bit of lift going on.That cam is getting serious.
Good luck with whatever you choose.
 
Much better carbs out there to use..and those Mopar cams are old and outdated leave em' on the shelf,look into others...
 
Is the car still together? If so, the first thing I'd do is go out to the driveway, apply that trans brake, and floor it to see what type stall speed you really have?

I'm not a fan of the MP.508. While you may have enough gear for it, it really only works well in a fairly narrow combination range. These days I'd only use it for sound while mild cruising or doing the fairground show circuit.....not performance. Just too many different/better grinds available now days depending what your combo (converter/compression) really turns out to be...
 
stroked340 said:
Much better carbs out there to use..and those Mopar cams are old and outdated leave em' on the shelf,look into others...
Click to expand...

The car is old and out dated. Should he leave it on the shelf too?
 
I had that cam in a 360 and thought it sucked. It sounded bone stock with no lope at all. I advanced it 4* and even with a stall it was sluggish. If I remember correctly there was something wrong with the base circle on those cams which added to the trouble...
 
Hmmm, No lope at all? And sluggish?
Did you bluprint it before you removed it?
Maybe there was something wrong with YOUR cam. Or perhaps,there was something off in your combo.

I had that cam. It pulled like a freight train. Mine had a very nice lope to it. It likes compression. At least 11/1.And a ton of ignition timing.
 
OldmanRick said:
Is the car still together? If so, the first thing I'd do is go out to the driveway, apply that trans brake, and floor it to see what type stall speed you really have?

I'm not a fan of the MP.508. While you may have enough gear for it, it really only works well in a fairly narrow combination range. These days I'd only use it for sound while mild cruising or doing the fairground show circuit.....not performance. Just too many different/better grinds available now days depending what your combo (converter/compression) really turns out to be...
Click to expand...

Actually the correct way to do that is with it running, shift the car to high gear and gently apply the gas with the brake held and parking brake applied and watch the tach. When the RPM no longer climbs, there's your stall speed.
 
rtee007 said:
Going to freshen up this 360 and the question here is the combo of:

Camshaft-P4120233AE
.508/.508 lift 292/292 duration 248/248 duration @ .050 centerline of 108 2200-6500 rpm Another camshaft option might be the P4120231AE: .484/.484 lift 284/284 duration 241/241 duration

Transmission-it is a 727 (no idea of the stall-but does have a trans brake)

Gear-Was told it is 4:56 SG and this appears to be true (spinning wheel and counting yoke rotations- a little short of 5)

The 360 has an Eddie Air Gap intake on it and a Eddie Competition Carb. I don't have funds to change the tall gear right now, but maybe next year I would reduce it to 4:10's, maybe some heads next year as well.

Appreciate any thoughts here, like to buy and get the camshaft installed and this engine wrapped up by next weekend.
Click to expand...

There's a few missing items of information.

Actual compression ratio
Headers and exhaust size
Actual stall speed of the converter
Tire size (not rim size)
What heads do you have on top and what are the valve sizes and are they ported?
Do you know what they flow? (Less important)
How heavy the car is

On the surface, (what you wrote) and based on as cast heads (stock or Edelbrock's) if you have the proper stall (as in enough) the Purple 292/.509 cam will work OK with the gears.
I would rather see (if your going to use a Purple cam) would be the 296/.557 mechanical cam with 1.6 rockers on at least a set of bowl porter & basket matches heads.

I'd like to see you compression ratio of at least 9.5-1 (iron) 10.5-1 (aluminum) more compression the merry up to the limits of the gasoline octane available to you.
 
You must log in or register to reply here.
-

Back
Top