Both are hydraulic rollers, replacing a 286 adv, 230 @ .050 .639 lift hydraulic roller, which replaced a 296 adv 231 @ .050 .621 lift that made more power with quite a bit less compression than the current cam:

here are my two finalists:

ultradyne 292/302 advertised 240/250 at .050 158/168 at .200 .600 .600 lift 110 (or 112 he said) lob sep, intake centerline I forgot.
cammotion 296/303 advertised 240/247 @ .050 160/168 @ .200 .619 .629 lift 110 lob sep, 105 intake centerline

Both have unsymmetrical lobes.

What effect would the larger advertised duration on the cammotion cam have versus the slightly smaller adverstised duration of the ultradyne? and what does the smaller .050 on the exhaust on the cammotion cam mean even though it has a slightly bigger advertised?

my combo is below.. any and all comments (except those attacking hydraulic rollers ;) are welcome).

1970 Chevrolet Chevelle SS
4020lbs with driver
462 CID BBC
4.282 bore
4.00 stroke
10.15:1 CR
Eagle 6.385" rod
1.7 Ratio Crane Roller Rockers w/ crane girdle
COMP 928 Springs (new last year)
COMP Hyd. Roller lifters (new last year)
Carb is holley 4779 750cfm DP upper w/ 850 cfm DP baseplate, 73P 80S jetting.
Carter 120gph street pump, 1/2 line from tank, 3/8 line pump to carb. (being replaced with carter 172 and 1/2 line all the way to the carb)
Edelbrock Performer RPM Rect Port Intake
Dart 320cc rectangular port runner aluminum heads, 2.250 intake, 1.880 exhaust
no porting. 119cc chambers milled to 116.5
SRP forged pistons, domed to make 10.15:1 w/ 116.5cc chamber
TH400, 3400ish stall speed 9.5" converter
3.90 rear axle,
10.5R15 considering 28*10.5R15 " MT ET Street, street use is 25.6" BFG p315/35R17
93 octane
Dual 3" exhaust (considering balance pipe), but I need to get my screwed up transmission inspected/fixed before this)
2" primary hooker super comps

thanks everyone..
matt

Well, about those squishy rollers.... smile.gif

Matt, just be sure that those advertised numbers are measured at the same lift ( usually .006 OR .026 in Ultradyne's case). If they are given at different heights, then the durations may not be different at all.

In fact, those cams look darn similar.

Are Ultradyne hydraulics measured at .026, or just the solids? And I may be doing things backwards here, but would a 292 at .026 be larger at .006?
and how much does .019 or .029 lift really matter in reality?

Thanks.
Matt

If you've ever degreed a cam, 10 thou lift makes a decent difference in the measured durations, for sure. Look at the difference between seat and .050". Just saying that there might not be much difference in the seat durations at all there. Also, take it from a guy running pretty large ports in a 439ci, stab that cam in +6 degrees AND keep the lobe separations tight to help intake velocity.

Those hydraulic rollers seat numbers are measured at .006" cam lift, to give comparable seat numbers to Comp Cams. I have always used either .0045" or .006" as a seat duration height, both in hydraulics and in hydraulic rollers. They have very similar ramps.

UDHarold