As I suspected, and your seat of the pants dyno observed, with your current setup power peaks at about 4500rpms, at 280hp. 330 ft-lbs at 3500 peak, with a strong torque curve but power falls off a cliff by just after 5K. I made some assumptions here...log type manifolds, and 600cfm exhaust flow. I assume this engine is 9-1 compression because you put dished pistons in it? In any case, this would be a nice daily driver package. Pretty much any cam I tried hurts midrange torque (some worse than others) with minimal top end power gains. A few of cams I ran thru came out with interesting results though. The crane 278 powermax (222/[email protected]
, .467/.494, 114lsa, 109 ica) hurts the least on the low end with a nice power increase at 4500, and peaks at 5000 rpms with considerably less drop off up to 5500 rpms. Increasing the compression to 10:1 makes that cam work even better, peaking at [email protected]
rpms, with minimal low end torque loss. GM's -151 350hp 327 hydraulic also makes a good showing, but it too needs 10-1 compression to really sing (and keep the midrange torque up). The best cam I tried was the -178 GM solid (LT-1 cam). With 10:1 compression, it makes over 50hp more at peak than you current setup, pulling well to nearly 6K. I don't know if I believe the low end torque numbers, but if they are close to true, it would pull similar to your current setup with much greater top end power. And, the 278 crane, -151, and -178 have nearly identical cranking compression numbers as what you have now...meaning that whatever fuel you are running now you could still run with 10:1 compression and one of these cams.
I also took the liberty of running your current setup as is, only adding a set of 1 5/8" x 34" headers. It spanks the other combo's up to 5K, with considerably less dropoff past 5K.
According to the program, to get your power to peak up around 5200 rpms with a 110 lsa hydraulic cam, you would need a cam of about [email protected]
, but any cam in that size range with your current setup just kills your power curve under 4K.
As is, with your setup, the best power curve I found was with a small crower solid flat tappet cam. I don't have a catalog handy to give you a part number, but its specs are 230/[email protected]
, .456/.458 lift, 112 lsa...its listed as a "pro street" solid. That cam, per the sim, gives just a minute amount of torque loss at 2000 rpms, and then takes off from there, peaking at 5K, with minimal drop off after that. If you have the 981-16 comp cams springs, the crower solid should work well with them. If your not opposed to a solid, then this appears to be the cam for you.
This is just a sim program, but the numbers are believable.