68 gtx cam advice

[68gtx]

hello all,
as i am new to the dodge world, i would like to ask your opions on a cam for my 68 440 gtx, engine is basically stock, and the cam in it sounds like my grannys car, previous owner said he built it stock as he needed it to pass aircare.. well where i live we don;t have any aircar to worry about... i would basically liek it to sound better, lumpy idle but driveble.. was thinking about a mopar perfromance purple shaft cam, but don;t know which one to go with... car is an auto trans , manual brakes , something equivillant to the way a chev 350horse 350 cam sounds.. can anyone here point me in the right direction.

 

[NovaSS]

not any adive except when it comes to cam choice use the 800 numbers and call the cam company of your choice. Be honest about you want to do and how you drive. Most street / strip combos only see several runs down the track in their whole life.

 

[MCODECUDA]

I used a Comp Cams Magnum 270 in my stock 69 GTX and loved it. I rebuilt the engine and put in a Mopar 282-484 and hated it. With 323 gears, 11" converter, cast iron exhaust manifolds, stock intake and carb I couldn't even spin the tires. I put in the Comp Cams Magnum 270 in it and that all changed.

 

[rrunner]

I used a Comp Cams Magnum 270 in my stock 69 GTX and loved it. I rebuilt the engine and put in a Mopar 282-484 and hated it. With 323 gears, 11" converter, cast iron exhaust manifolds, stock intake and carb I couldn't even spin the tires. I put in the Comp Cams Magnum 270 in it and that all changed.

Did you degree the purple shaft? In most cases we have had to advance them about 4 degrees and have made power with the 484 cams.
If you are looking at Mopar cams and won't be changing the converter or valve springs, if running the 68 HP single with dampner springs, the 474 is the largest cam I would run and make sure you degree whatever cam you install.

 

[MCODECUDA]

Did you degree the purple shaft? In most cases we have had to advance them about 4 degrees and have made power with the 484 cams.
If you are looking at Mopar cams and won't be changing the converter or valve springs, if running the 68 HP single with dampner springs, the 474 is the largest cam I would run and make sure you degree whatever cam you install.

We advanced it and it didn't make much difference. I ended up putting it in my cuda which has headers, 10" converter and 3:55's and that made all the difference in the world.

 

[Meep-Meep]

I'm running the .455" / 272 purple shaft in my 440 and it runs great. My compression is at 10.1:1 and it blows 190 PSI of cylinder pressure, which is a bit much for pump 91 gas. I think a half point less compression would put me right at the pump gas limit. The .484 will require more compression to work properly so I'd stay away from that one.

 

[Osyman]

This is interesting as I'm building a 67 hp 440, 915's, 10.1:1, stock rockers, edelbrock intake, 770 street avenger, with a stock converter. The purple cam 280/484 will be too much for my motor with 3.23's?

 

[MCODECUDA]

This is interesting as I'm building a 67 hp 440, 915's, 10.1:1, stock rockers, edelbrock intake, 770 street avenger, with a stock converter. The purple cam 280/484 will be too much for my motor with 3.23's?

Stock converter for a 440 is 12", 340's and 383's used 11". There are better cams out there than what Mopar offers. I'd contact sombody like Hughes and get thier opinion on what to use for your combination.

 

[GTX MATT]

It depends one what else you want to do to the car. If you want to leave everything else stock keep the LSA at least 110, preferably 112-115 and keep the duration at .050 under 225 on the intake, maybe 230ish on the exhaust but even that is a bit much. Something around 215/225 for intake and exhaust with a 112 LSA will give you a bit of a gallop like a stock HP cam.

The 272/272 purpleshaft works nice with manifolds and tall gears and will give a little gallop, not too much though.

 

[68gtx]

i see comp cams has thumper series cams anyone tried these?

 

[Meep-Meep]

This is interesting as I'm building a 67 hp 440, 915's, 10.1:1, stock rockers, edelbrock intake, 770 street avenger, with a stock converter. The purple cam 280/484 will be too much for my motor with 3.23's?

I wouldn't use that cam unless you had more gear. My engine with the .455" runs low 13's @ 109 MPH on street tires (not stickys) and full 3" exhaust with 3.55 gears. This is all in a full bodied all steel 66 Belvedere.

The next cam up is the .474" and it works well, but again you should have more gear. The published RPM range of the .455" is 1500 - 5800 and with the 3.23's I think it's perfect. The 112 LC spreads the torque out over a broader RPM range then say a 110 or 108 so it's much more friendly with taller gears in a daily driver situation. It also has good vacuum, which helps with power brakes.

 

[68gtx]

I used a Comp Cams Magnum 270 in my stock 69 GTX and loved it. I rebuilt the engine and put in a Mopar 282-484 and hated it. With 323 gears, 11" converter, cast iron exhaust manifolds, stock intake and carb I couldn't even spin the tires. I put in the Comp Cams Magnum 270 in it and that all changed.

What did it sound like with the 270 in it?