Split duration V. single pattern

[pontiacvince]

Anyone have any preferences on split duration vs. single pattern cams? My cam is the Comp 26H with .212@.050 and .440 lift. I'm thinking of adding the 1.6 rockers on the intake side for a little more lift and a couple degrees more duration.

[Sheepdip]

I'd call Comp Cams for advice....but that's just me.

[basketcase]

Lots of opinions on this topic but basically a dual pattern cam has more lift or duration or both on the exhaust side to compensate for a poorer flowing exhaust port like on a stock head. If your exhaust ports are ok for the cam and rpm you are likely to run most of the time, then a single pattern cam is just fine. Also adding a 1.6 rocker on the exhaust side will help crutch a poorer flowing port to a point. Adding it to the intake side only would further overload a poor exhaust port. If you are going to add a 1.6 on the intake side, do it to the exhaust side too but be sure to check valve to piston clearance. You will be going from .440 up to about .469 lift. Most stock heads would take that but if they have been cut before, block decked, and a .018 steel shim head gasket you could be real close to contact. I honestly don't think you will feel much difference in the lower to mid-range rpm and very little at high rpm unless you have some good heads.

Tom

[hugger6933]

I've used tons of comp cams over the years back in the day when I was racing I'd go over to their place to pick up my stuff since they are in memphis and I'm about an hour and a half away. For a basic small block set up I LOVE the 268H makes crazy power from stock adds gas mileage to boot adds vacuum it just makes the motor happy. I have ran dual energy 278 it is a little large and you probably need springs for that and it will hurt drivability some but your truck will sound like a promod[ not really but ya know]. I'd stick with the 268 H just cause I old now and getting tighter with money everyday. If you do go with some 1.6 rockers on the exh side we once again are talking about checking for coil bid and really needing newer springs. Good luck and have some fun. Jim

[Myself]

I always heard.....dual pattern for the street, single for the track.

[Mike C]

I’ve always been a single pattern cam guy, but the Engine Masters shows says the split pattern cam ALWAYS makes more power. In the future I will most likely run split pattern cams if power is one of the primary reasons for the cam. But if a Comp 260 is the choice, driveability is probably one of the top reasons for that choice, and at that power level, probably not a whole lot of difference in that two.