Say, just how heavy do you think this RV chassis might get to be?
No, I wouldnt use that 6900. You see the advertised is 278*intake and its 204*@050. What that indicates is that it is super slow on the sub.050 ramps, requiring (278-204)/2 = 37degrees to get there. The 204 part is pretty good, but that late closing intake will really pull the Dcr down, and tend to kill low-rpm torque.Notice on the cam card they dont provide the valve timing events for the advertised durations? Well, I just worked it out. Using their specs, and assuming symetrically ground lobes. the intake closing event comes out to 70.5*ABDC. And the overlap works out to 59*. That makes for a big cam sounding idle and not much else, unless you start with some really good compression.No I wouldnt use that for an RV application.
Ima thinking the intake closing point should be in the neighborhood of 50 to 55 degrees. This could still be a 204@050, but maybe 245 advertised. Thats a fast-rate of (245 - 204)/2 = 20.5degrees to get up the ramp. This cam wont make a lot of power. It will make a lot of torque with a minimum amount of compression.If you start with 8.5 Static cr,and 55*ABDC, this will only drop your Dynamic cr down to about 7.3.Whereas the 6900 will drop the Dcr down to 6.5. You see what I mean. Thats a .8 difference right where you need it, getting off the line.
If you had a 9.5 Static the numbers would be 8.1Dcr for the 55*closing, and 7.2Dcr for the 70.5*.