question on the free height of my valve springs

[troy.70R/T]

Well I am working on a used but good running 383 motor. It is a 65 with 915 heads. I think it was a 2 barrel lower compression one because the pistons are dished and not flat tops  It is stock bore and I assume a stock cam. Well I took a few springs off just to see what the valve seats looked like. I measured four of the springs at free height and they all measure 2.300. The book I have (How to rebuild Big Block Mopar engines) says that the free height should be 2.580. I assume this is just for stock cams. I have no way to check the load of the springs. I was going to use a mopar purple shaft that was new that I had lying around but not sure if the springs are even good. any thoughts?? o yea the cam spec on the purple shaft are lift .474 duration 280 overlap 60 centerline 110.  If I do need new springs what should I get if I want to run this cam.

[troy.70R/T]

I also measure some springs from a diffrent head I had and the four that I measured were 2.400

[John_Kunkel]

'65 FSM says the 383 spring free length should be 2.340". New is always better than used.

You didn't ask but I think that Purple Shaft cam in a low-compression motor will be disappointing.

[troy.70R/T]

well if everything is factory on this motor I looked in my MOTOR repair manual and and 9.0 is the low compression motor and 10.0 is the high compression motor. I know my 70 charger is 9.7 and has the about he same cam. it was built about 20 years ago so that all that was avaliable.   so would those valve springs be ok to use with the purple shaft cam or not. when you say you dont think I would be happy with it is it cause of the low vaccum? the car has manual breaks so that is not a problem. just wondering if I should just leave the factory cam in. Less work to do that anyway.
thanks John.

[BSB67]

well if everything is factory on this motor I looked in my MOTOR repair manual and and 9.0 is the low compression motor and 10.0 is the high compression motor. I know my 70 charger is 9.7 and has the about he same cam. it was built about 20 years ago so that all that was avaliable.   so would those valve springs be ok to use with the purple shaft cam or not. when you say you dont think I would be happy with it is it cause of the low vaccum? the car has manual breaks so that is not a problem. just wondering if I should just leave the factory cam in. Less work to do that anyway.
thanks John.

No, Don't use the old springs.  I would not recommend that cam either.  Use a shim head gasket when you reassemble

[troy.70R/T]

Thanks BSB67 this is not an engine rebuild I just bought the motor to put in my 68 to get it running. Well long story short I don't want to put any money into a 383. It is not a number matching motor for my car i just want to drive it while I get parts rounded up over the years. I guess I will never get to use the cam eveyone tells me not too. Should I just throw the cam in the scrap pile??

[John_Kunkel]

Save the cam for a more appropriate build or sell it.

[troy.70R/T]

Id rather just sell it but it doesnt sound like anyone would even want it. Maybe I should put it up for trade i might have better luck with that.

[Dino]

I have an old purple cam in a low comp engine and it's not very exciting until you hit the higher rpm range.  It'll be replaced soon and I'm not even going to try to sell this paperweight.  I see wall art in its future.