bbm head question

[fryedaddy]

i ordered a set of bbm heads last year and installed them on my 433.when i ordered them i told bbm tech my cam specs.im running a 565 lift cam and i noticed on the bbm site that the heads i bought were the single spring with damper setup.the bbm site said they were for 500 lift,550 max lift.will this be ok with my 565 lift cam or should i have gotten the bee hive set up good for 600 lift.im a little confused,im not a engine builder and i dont know if the 565 lift is ok since the site says 550 max. i know this is probably a dumb question but i just wanted to know for sure

[fryedaddy]

hey fryedaddy,that is a dumb question.no wonder you havn't got a answer!

[Joe-JDC]

Only way to know the answer is to check piston to valve clearance, installed height, spring seat pressure, and over the nose pressure at .565" lift and check to see if the retainer clears the valve stem seal, and does not coil bind at maximum lift.  If you have .050" clearance between coils in springs at max lift, and there is .070" intake clearance, and .100" clearance on exhaust valves at maximum lift between the valves and piston eyebrows, then the only thing you need to know is if those figures fit your cam card specs.  Simple, right?  If they said the springs are only suitable for .550" lift, then most likely they need to be changed for a better spring.  Sometimes a set of springs will actually be suitable if all those parameters are met, with a .015" shim under the seat cup, and check the pressures again, or maybe a .030" shim will get you there.  Would need to check coil bind again.   Any competent machine shop should be able to set up your heads easily and quickly if all you need are different springs.   Joe-JDC

[fryedaddy]

thank you Joe,i understand now. my local machine shop is a old fe guy and a 40-50 year bracket racer.all the local racers go to him, im sure he will help me out.

[CaptCobrajet]

If you bought the heads assembled from BBM for a flat tappet cam, and the shipping label came from Blair Patrick Enterprises, they are Comp Cams 911 springs.  They are installed at 1.900, and coil bind is 1.200.  They should be fine to .600 lift.  His site says .550 to stay conservative, and as a precaution about guys who might have too much nose pressure with higher lift flat tappets.  From what you describe, you should be just fine.

[fryedaddy]

Thank you Blair,i told them over the phone it was for a flat tappet 565 lift.i cant remember if bp was on the shipping label.i remember telling them i was staying under .600 with my cam so i should be fine.