valve spring selection

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67moparfan

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hello all, I found a broken inner valve spring on my Dart.
unfortunatley for me, I dont know exactly what cam I have in it, it came with the car.
I believe its the P4120657 Mechanical Flat Tappet, Adv. Duration 312/312, Lift .590/.590.
I did measure the lobes when I had it out and matched the .590 part with my 1.5 rockers.

I have Brodix B1 BA heads, the Brodix site lists:
Valve Springs:
1.550 Roller Valve Spring - GA 1000,
240 lb Closed, 550 lb Open,
1.950 Installed Height,
.700 Maximum Lift
(B1 BA, B1 BS)

but the info I found for the springs for this cam is:
Installed height 1.70”
o.d. 1.45”
lift .610”

any help with spring selection would be greatly appreciated.

*I have not removed a spring yet to measure, I need to make a tool to remove them on car since these heads have different shaft towers than stock.

 
I'd think the MP cam requires a lot less valve spring than the heads would come with. I would say remove a few, measure the installed heights, and see what pressures they test to. I may go slightly heavier than the recommended spring in some cases but generally the lightest springs that will work are best - based on the installed hieghts and reccomended pressures from the cam manufacturer.
 
thanks, the installed height is what has me worried, because I dont remember seeing any shims under the springs.
I am attempting to make a tool to remove them on car tonight.
so hopefully I can get them measured tomorrow.
 
That is the same cam I run. Just put new springs on mine. I used Comp 928-16 Installed at 1.92 155lbs. on the seat and 355 open.
 
I went with Comp 933-16 per an engine builders recommendation after giving him my info. *i removed one so he could measure it*

I was able to make a tool out of 5/16 square tube and welded 8 bolts to it mimicking a GM style head so I could use my brothers valve spring tool...worked out pretty sweet.

the old springs were definitely easier to remove than installing the new springs.

but without changing anything else, it ran faster than normal (comparing to up-prepped track conditions). so I can assume I was on the edge of valve float with the old springs.

happy to say I still beat on my brothers 406" 600hp Nova!! but he was having fuel issues with the regulator (so he says).

best of night was 10.93 @ 122.32 1.55 60ft, normally run 10.99-11.02 @ 120
 
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