Originally Posted by jtz55
are u running headers or stock exhaust .I have and am currently running a similar setup 485 lift cam 5.7 rods .it is putting out alittle over 400 hp and 525 ft lbs very good street manors .have fun with your 400 they make tremendous off idle torque and will shred the belts off most street tires.
varified or estimated?
the 400 came with 265 hp plus or minus
using a decent upgrade in cam/manifold/carb/headers could net 50 plus hp
vortec heads are very good improvement over most heads,especially for moderate performance and low lift cams.
vortecs flow 230 plus CFM on the intake side
these heads would peak at 5500 rpm on a 400.the cam would need to be big enough to rev 5500 to take full advantage of these heads
may need exhaust port worlk