javierant3

Hello, I have a problem that is driving me crazy. One year ago I dismantled my head because my camshaft has destroyed a tappet. I take out the tappet but the head but in the process the tappet bore were scratched and because of that injury to the head I prefer to change them and go for a new cam and tappets. I mounted newman phase 1 cam with hydraulic lifters.

After this my engine runs very good but for 4500rpm and up the engine apparently will make no more power. The engine sound changes and really I had to change to another gear because the engines lack of power.

Now I have changed the newman hydraulic tappets, because they were noisy and I think maybe the fault were in it. With the mechanic ones I can rev more but also passing 5k or 5.5k rpm is difficult, the engine sound changes and loses power.
I have been told that because mechanic lifters are lighter than hydraulic ones my engine goes higher, but the problem persists.

I have checked all the other things in my engine. I have new plugs, twin 40 DCOM carbs freshly rebuilt slightly ported head and MFI exhaust manifold.
With that setup I expected to rev up to 6k rpm without mayor problems.

I think that I would have valve rebound. I dismantled the original springs with the CVH spring compressor tool and maybe this had weakened the springs...

Help will be very appreciated.