A very commonly made mistake is to assume in cases like this, where you have a combo thats performing fairly well,but needs a bit more upper rpm power, that you can make a fairly radical increase in cam duration, too gain that required increase in upper rpm air flow rates, too potentially increase power while not adversely effecting the lower rpm power. OK looking over many dozens of some what similar builds its rather obvious that you can very easily reach a point where you can reach or exceed a tipping point, that will have you trading off that mid and low rpm torque for increasingly lower gains.
the first cam you linked to would in my opinion be by far the better choice of the two you selected, but even thats likely to be just a bit to large of an increase, to effectively match your combo, every choice is a compromise, adding 8-10 degrees duration should move the whole power band up 500 plus rpms
http://www.lunatipower.com/CamSpecCard. ... mber=60133
yes you could fairly easily in this case increase the duration to about 8-10 degrees more and add a bit more lift, I would certainly think after doing a few software dyno comparison runs that a cam in the 242-244 duration @ .050 lift, and ..558-.600 lift range would get you to where you want to be, but ID sure try to find one built on a 108-110 LSA to try to maximize the mid rpm torque so you don,t loose a great deal more that you intend to, because with a 3.54 rear gear and only 10.5:1 COMPRESSION, and those valve spring load rates, you could easily trade off far more low and mid rpm power for minimal gains if you get to radical on the cam selected.
keep in mind that your valve springs won,t work well at maintaining valve train stability if you increase the lifter acceleration rates much more that the current cam, with those valve spring load rates, so altho there will be a tendency to want to go with a cam with greater lift increasing the lobe acceleration rates will cause stability issues AND RUNNING HYDRAULIC ROLLER LIFTERS YOUR NOT GOING TO BE ABLE TO SIGNIFICANTLY INCREASE YOUR USEABLE RPM BAND MUCH OVER THE CURRENT CAM, WHAT YOU CAN DO IS MAXIMIZE THE TORQUE CURVE IN THE 4500RPM-6500RPM RANGE.
heres my choice
A MECHANICAL ROLLER LIKE THIS CROWER LISTED BELOW IS MOST LIKELY A GOOD OPTION
JUST as a bit of info I used this crane roller (#119651) in a 12:1 compression 406 engine build with similar but slightly smaller brodix 215cc port heads heads and a single plane intake to push a 1988 corvette one of my friends owned into the mid 10 second range so with your larger cylinder heads you should not need a huge cam duration increase
viewtopic.php?f=32&t=430&p=529#p529