Weak springs?
Hi,
I have a Crane TR-272/4167-2S-10 cam in my 509.
The cam card says:
1967-UP CHEVROLET V-8 396 THRU 454 CU.IN.
MODERATE COMP. ONLY, GOOD UPPER R.P.M.
TORQUE & H.P., HIGH COMP. RATIO REQUIRED
INTAKE @CAM 4167 @VALVE 708
EXHAUST @CAM 4167 @VALVE 708
TIMING OPENS CLOSES ADV DURATION
@ .0195 INTAKE 45 BTDC 85 ABDC 310 °
TAPPET LIFT EXHAUST 88 BBDC 48 ATDC 316
@ .050 INTAKE 29 BTDC 63 ABDC 105 °ATDC 272 °
TAPPET LIFT EXHAUST 72 BBDC 26 ATDC 115 °BTDC 278
RECOMMENDED RPM
RANGE WITH MATCHING COMPONENTS
MINIMUM RPM 4400
MAXIMUM RPM 7800
VALVE FLOAT 8500
So not a street cam, but not a pro-stock cam either.
The valve spring recommandation:
Crane-99876
LOADS:
CLOSED 160 LBS @ 1.968 OR 1 31/32
OPEN 490 LBS @ 1.308
I have installed them on 1.950" which gives 160-180lbs seat pressure new. Few questions. Is this enought as the rpm at finish line is about 7000? Should I upgrade the springs? Spring recommadations for 1.55 size? Heads are with 2.19/1.88 stainless steel valves. I had about 50 runs on new springs and lifters when we took it apart. Springs are now 150-180lbs at the seat. Valve seats and lifters seems to be fine.