Here are a few GM cam timings that might be helpful.To calculate the proper tappet lift at which to measure the seat to seat duration for a solid lifter cam:
Divide the lash by the rocker ratio and add .004".For the 097 cam below, the proper tappet lift to use is .012" (.012/1.5+.004). The actual seat to seat duration is 272º not the 287º Chevy claims. I've highlighted the proper tappet lift for the ones that fall in the table.
Chevy 3736097 ( intake lobe )... Chevy advertised dur is 287 deg... lash @ .012.
Lobe Lift ,...... Duration......
.008 ____________ 288
.010 ____________ 278
.012 ____________ 272
.014 ____________ 267
.016 ____________ 264
.018 ____________ 261
.020 ____________ 258
.050 ____________ 228
---------------------------------------------GM 3849346 ( 30-30 Duntov ).Chevys advertised duration is 346... lash .030.
.008 ____________ 440
.010 ____________ 418
.012 ____________ 396
.014 ____________ 375
.016 ____________ 354
.018 ____________ 331
.020 ____________ 314
.050 ____________ 254
.024" is the proper tappet lift. It's not on the table. Further date points to the .024" duration being 304º.
---------------------------------------------Chevy 3925535 ( intake lobe ) L88 cam.Chevys advertised duration is 354,Lash .024 ??
.008 ____________ 395
.010 ____________ 374
.012 ____________ 353
.014 ____________ 336
.016 ____________ 324
.018 ____________ 316
.020 ____________ 309
.050 ____________ 264
---------------------------------------------
-929 chevy cam
006" 253/264
.050" 193/202
.200" 96/105
LCA 112
Intake cl 107---------------------
Chevy Hot Cam:
Hydraulic Roller
adv--dur________279/287
.050___________119.1/229.3
.100___________187.7/197
.200___________135.8/143.1
LSA___________112
--------------------To Dynamic Compression Ratio PageThese are the only cams I have this data for. If you have others, please send what you have and I will post it.