I have a 212 predator hemi block withe +.020" billet connecting rod,stock 70mm flat top piston and wrist pin,.275 high duration cam,.045"head gasket 26lb valve springs,1:2 ratio champion rockers,the stock 27mm/25mm valves stock retainers and lash caps,and the head is a big valve non hemi head running 26mm nibbi round slide carburetor stock heating. My problems is at 5900 rpm it start acting like it wants to keep pulling but then it dies out then I can gently apply throttle it will do the same thing over??? Any help please