cam choice

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6tfo

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The engine below is out of the car and heads are off. Reading through many posts on A bodies I'm feeling that the cam is too much. I'm trying to decide if I should replace the 474/284 cam before putting the engine back together. Any thoughts? I'm a purely a novice when it comes to these engines.

1973 340 bored .030, stock type pistons.
J heads - intake 1.92 exhaust 1.88, 3 angle valve job, eagle springs
purple cam (4120231) 474 lift 284 duration
Edelbrock RPM air gap manifold 7576
MSD 8534 distributor
MSD 6AL
Edelbrock 1806 (650cfm)
tti headers
 
what you need to include is ...is this a street car?

automatic or 4 speed..? if auto ..what converter and what gears...

but generally the 284/484 cam is alot for a low compression engine..and might give ya problems with power brakes...

mopar says it has 241 degrees of duration at .050...depending on what you are looking for in idle quality ...i would look for something around 220 plus or minus a few degrees

http://www.summitracing.com/parts/LUN-60402LK/

there others available from comp cam.....




by the way...you heads have 1.88 intake and 1.60 exhaust...
 
Thanks for the response and correction to the valve sizes. A727 tranny, sure grip 742 case 3.55, disc brakes front, drum back, no booster. I've also considered going with big valve heads but that would not help the compression, right?
 
Forgot to add that I'm waiting to figure out the engine before choosing the Torque Converter.

Thanks.
 
6tfo said:
Thanks for the response and correction to the valve sizes. A727 tranny, sure grip 742 case 3.55, disc brakes front, drum back, no booster. I've also considered going with big valve heads but that would not help the compression, right?
Click to expand...

the compression in the 73 340 was lowered by changing the piston's compression height...

you can mill the heads some and use a thin head gasket to help...

unless you need to do a valve job on the heads...i would leave the 1.88 intake alone...

if the heads need complete rebuilding...i would change vavles ...use small block chevy 2.02/1.60 that are .100 longer...

Or look at a set of RHS Indy X head.....but it all comes down to money....
 
Appreciate your thoughts Tony. This will be primarily street but I don't want a wimpy 340 either. These days my time is more valuable than money (I don't have enough of either) but if I thought the Indy or Eddy performance heads would help this situation I'd invest. Of course it's my haste that landed me with a low compression 340 with an oversized cam.
 
That Mopa cam is fine for what it is in. More comprsion creates more vaccum. A bigger cam creates less vaccum.
 
I wouldnt run it with that piston and head choice, but that's me. I think there are much better choices in terms of driveabbility and power to go with those stock pistons. In fact, of all the minor changes one can make in a rebuild, the pistons are top of the list. I'd use the Comp XE268. The Lunati needs some head work (in terms of guide and spring seat) to run the matching springs. The Comp will go right in with single springs.
 
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