hello

I have heard nothing but excellence from the 268xfi cam. However, it is usually used with 1.6 rockers. That is a problem for me becuase i have 1.5 roler rockers already.

I called Cam help from comp cams and told them i wanted the same numbers as the 268xfi with 1.6 rockers with my 1.5 rockers, so what xfi cam do i need to go with my 1.5s to match the numbers on the 268xfi.

they told me to get the 280xfi for my 1.5s and that will be just like the 268xfi with 1.6.

i do not know much about cams, but im not so sure what they told me is true.

Please help me out, im 16 and this is my first build

Lee

 

Im not an expert and dont know hte answer to your question but Im sure Comp Cams wont steer you in the wrong direction.

 

well, from the little that i know
summit part number CCA- 07 466 8 and CCA 08 467 8
the 268xfi has a 050 inch lift duration at 218/224

the 280xfi has a 050 inch lift duration at 230/236

this would make the 280 a great deal more "lumpy" than the 268. thses two cams are not really that close. I just cant beleive that this is what they recommended for my situation.

Speed

 

Thats a pretty signifiant jump in cam, since 1.6 rockers only have about 6% more lift than 1.5 rockers, I would think the difference would be much smaller than theyre recommending.

 

The 280xfi has a lot more duration than the 268xfi and will make power at a higher rpm because of it. These two cams are not at all the same. Cam durations change very little when going from/to 1.6 rockers/1.5 rockers. It's lift that will change by using different rockers.

The 280xfi is a very big cam for a tpi engine.

 

I'd go with the 268 and get some rockers. The ramps are already very aggressive, no way you're going to find a cam with more lift at that duration with 1.5 rockers.

 

Get the 268 and keep the 1.5s.

 

will that be enough lift????

that wil give me about 536 on the intake and 531 on the exhaust.

Speed

 

Can your heads take advantage of the extra lift? I fell into the more is better thinking awhile back when I bought my rockers, went with 1.7s. They added a rougher idle and zero mph in the 1/4. The XFI were designed to run 1.6s though, so it is a little different. If you have the coin, trade up, but I would try to make it a minimal investment.

 

Want to bet?