Cams

[BHDave]

Just trying to get my head around a few things regarding aftermarket jap cams for rb25's,

For starters you can get step 1 hks 256/264 which are about 8.8 to 9.0mm lift, and poncam 256/256 about 8.8mm lift which are drop in with stock springs, retain vct and give a nice gain without requiring cam gears, though a retune helps.

Whats to stop me dropping in tomei procams that are (say) 270/270 with bigger lift (10mm plus from memory), swapping the valve springs and getting an exhaust cam gear but retaining the vct. Or even running a low duration around 256/256 with the big lift.

Is there an advantage in running short duration big lift? Or on the flip side is there an advantage running big duration low lift (like the old apexi drop in 280 cams)? Where is the happy medium and is there any advantage/disadvantage to retaining the vct with big lift cams or will it just put a valve through a piston when running long duration/high lift cams?

Thanks guys