Leave it like it is until the warranty has expired. Then come back and see what the new designer cam is. Odds are the hot over priced ones you see now will be replaced with something purportidly better and certainly more expensive - then go buy the current day cam for half the price. If you want a high lift cam be prepared for the full deal or save for a major rebuild in the future.

 

The only thing about higher lift cams is they really don't come into play unless the heads are designed to benefit from the higher lift. In other words why run a 575 lift cam if the heads stop flowing at say 510. What benefit would you gain. I trying to think where I saw a chart on the cfm flow on stock heads at different lift, I'm thinking it was on another forum but it showed around 510 or so was about it at the time the chart was posted.

Here are the flow numbers for Dewys pro street ported heads with 1.900 in. and stock ex. @10" h20 multiply number times 1.67 to get @28"
ALL REAL NUMBERS

intake lift CFM Exhaust CFM
.100 = 37.4 / 27.1
.200 = 81.9 / 52.9
.300 = 123.9 / 87.1
.400 = 130.2 / 93.4
.500 = 127.0 / 96.6
.600 = 128.1 / 100.3

SAME DAY - SAME FLOW BENCH
STOCK HEADS NUMBERS are :

.100 = 33.8 / 26.1
.200 = 72.8 / 53.9
.300 = 107.1 / 74.1
.400 = 122.9 / 86.1
.500 = 117.6 / 88.4
.600 = 118.3 / 90.3 Now after head work the benefit cleary showed gains with the higher lift cams. Im just say'n.

 

Wow, those are some pretty poor flow #'s. I didn't realize that HD heads were so restrictive. (even with some porting) The flow stalls at a relatively low lift, too. I'm used to seeing automotive (LSX) flow numbers around 300 CFM+ for the intake and mid 200 CFM flow numbers for the exhaust. Is the basic design of the HD head the limiting factor? (port layout, valve angles, etc.) Or is there just not enough material to work with to make them flow well?

 

Probably a good idea to wait but i just CANT!! i bought the extended 7 year and i want more pull now. I know there are lots of opinions on how or if the warranty will be void but thats why I'm having the local dealer do the work. As long as any repair needed is NOT a direct result of the cams the warranty wont be affected. In the end, like i said, "I just cant wait",,,,LOL

 

2 things, one being that chart was measured at 10" instead of 28" so the numbers aren't what is normally reported, and the Harley heads after porting will get over 300 cfm on the intake side with porting and oversize valves. The stock valves are tiny compared to automotive applications.

 

Gotcha, now I understand. It didn't make much sense until you explained that they flowed them at 10 inches of water as the method of measurment.

 

To get the numbers to a 28" just x them by 1.67. On the ported head at 600 lift on the intake the numbers would be at 213.27.

 

What is the stock cam in the 103 RGC?

 

You can find our answer here: http://www.andrewsproducts.com/PDF_f...s07-11-pg4.pdf