Alright well my 318 at some point in it's short life the pistons and valves got into a bit of a cat fight. Heads were rebuilt. Cause of the issue seemed to have been that the pistons did not have the proper reliefs for the 2.02 valves, also the lifter pre-load wasn't correct. Well after a makeshift fix for the valve reliefs (dont ask), and the pre-load set it's ran fine ever since. However the piston/valve clearance is plenty for the .480 lift cam that is in there...i would like to go more cam. I will be pulling it apart to check things out, fix a leak, give it new bearings and ARP rod bolts while I'm at it.
Question being, a very similar build that was written up in a magazine recently ran KB 167 pistons, a .525 lift cam and squeaked 415hp out of the .040 318. I would like to do something similar with the pistons/cam.
Here are the pistons I have now.
http://store.summitracing.com/partdetail...mp;autoview=skuHere are the KB 167's
http://store.summitracing.com/partdetail...mp;autoview=sku- Bottom end was balanced with the cast pistons. In changing from cast to hyper pistons, how vital is it to get the bottom end rebalanced? Spinning up around 6,300rpm.
- In changing pistons, atleast a hone will be required, correct?
- Right now the p/v clearance is just about at the proper spec, a little more, and there are just plain fel-pro head gaskets. The J-heads are milled to 56cc Chambers and it retains the factory deck height. In an attempt to gain a little more clearance, I do have some .060 head gasket shims that go under regular head gaskets, so it will bring the heads up about .060 than it currently is. It will give me a little more p/v clearance, however..The heads being milled, the previous owner had the intake milled to match the angle of the heads. If i bring the heads .060, can I do that? Or will it throw those angles off or is there milling that would need to be done. (if so, what/where)
Thanks.
Current Cam
Product Line: COMP Cams
Cam Style: Hydraulic flat tappet
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 230
Duration at 050 inch Lift: 224 int./230 exh.
Advertised Intake Duration: 270
Advertised Exhaust Duration: 280
Advertised Duration: 270 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.470 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.480 in.
Valve Lift with Factory Rocker Arm Ratio: 0.470 int./0.480 exh. lift
Lobe Separation (degrees): 110
New Cam
Product Line: COMP Cams Xtreme Hi-Lift Camshafts
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 2,000-6,000 RPM
Intake Duration at 050 inch Lift: 231
Exhaust Duration at 050 inch Lift: 237
Duration at 050 inch Lift: 231 int./237 exh.
Advertised Intake Duration: 275
Advertised Exhaust Duration: 287
Advertised Duration: 275 int./287 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.525 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.525 in.
Valve Lift with Factory Rocker Arm Ratio: 0.525 int./0.525 exh. lift
Lobe Separation (degrees): 110
