High RPM Backfire when fully warmed

TT5.9mag said

I use the hose from my compression tester and just plug it in to my air compressor. It runs at 120psi.


Search here there are threads about valve spring compressors.

Magnum Head Valve Spring Compressor

Click to expand...

I clicked on that link but nothing pops up that would work, one link is dead, and the other member made a tool. I see that Mancini has this MRE - Valve Spring Compressor

$125 But I rather not buy from him I have seen that he charges a lot for shipping for profit.

Is there a generic brand of this type of valve spring compressor?