The 1st one is:

230/237 .544/.543 112 I will run this cam with a 1.85 rocker, soo my lift will be increased to .592/.590

The second cam:

237/242 .595/.595 112 I wont run anything larger than a 1.7 rocker.

Soo, I was told with the lower lift cam, and larger rocker, I would increase my port velocity, which will increase my hp and torque...but would going to the larger cam see enough hp/tq gain over the whole powerband to justify running it instead??

Thanks guys.

 

what size engine is it going in?

I'm going to kind of do the 1st cam idea with my TR224/224....instead of swaping to a 227/224, I'll up the lift to 0.596" and this should give me more HP up top but keep the bottom end the same (torque)....

 

I am by no means an expert at the timing of valve events and etc... but running a higher lift with that duration you may want to check to see if it clear with P2V before hand, If you haven't already done so.

2001CamaroGuy, I assume your using crane rockers at 1.8, I thought about that but I am looking at doing the solid roller setup and forged bottom end, so those pplans are off for now. Actually thought about my friend and I getting a set of 1.7 and 1.8 and swap half of them for a reverse split but who knows.

 

I would like that one explained. Why would using a lower lift cam with a higher ratio rocker have more port velocity then a high lift cam using normal rockers? Doesn't seem like the valve would know the difference and and total lift would be same. The ramp speed of the big lift cam is still likely to be a bit faster (not so sure of this) so what changes the port velocity?

 

Your right.....a low lift cam (with a given duration....ex: 224/224) with 1.8 rockers vs. a high lift cam (with same duration...ex: 224/224) with 1.7 rockers would give the same amount of power (or close)...


What we are talking about is taking a smaller overall (lift AND duration) cam (ex: TR224/224 with 0.563" lift) and running 1.8 rockers to make it a 224/224 duration, 0.596" lift cam....

Vs....

Having a "larger" cam (ex" 230/230 with 0.570" lift) with 1.7 rockers....



What we are saying is the smaller duration/large lift cam (lift from the 1.8 rockers) will be a better driving cam and still make much of the larger cams hp (to a point) because.....

The smaller duration keeps port velocity and overlap lower thus improving low RPM performance (can actually idle below 1000RPM) but the high lift/ramp rates from the 1.8 rockers will still allow the engine to inhale the needed air/fuel mixture at high RPM.....



This is kind of the principle of why roller cams work so much better than non roller cams.....the roller is able to accelerate the valve to max lift faster and therefore the duration can stay smaller....thus improving low RPM vacuum while still getting the flow capability needed for high RPM performance.....



Now....like everything else, there is always a downside.....

We will be asking A LOT out of those poor little valve springs (even my Comp 987 duel springs won’t live as long as if I left the 1.7s......) so we might have to change the springs after a given interval to make sure we don’t start floating valves (say every 20K or so)..but at $90 a set for 987s, I can swap springs yearly.....

 

the way I see it, if you have a 224 cam with 600 lift then you have a 244 cam with 600 lift, the 224 cam will have a faster ramp speed over the 244. I think the 224 may have more duration at .500 lift giving it more port velocity becuse it is open longer while the head is flowing at its peak, this may be a good question for someone like pual at thunder racing

 

Okay, well these are both lunati cams, and that is what I was told by the guy I was talking to on the phone. I also was told this by a guy at Comp who had a custom grind sitting on the shelf which was a larger duration/low lift cam, and he was the one who originally gave me the idea of going with the 1.85 rockers...as for me explaining why...well I guess I worded my post wrong..I didnt really understand how/why that would increase my port velocity, but from what 2001CamaroGuy said, I understand it much better.