ok, ill start with the set up specifications....

- LS b18b1 obd1 head
- factory valve guides (never changed out)
- pretty extensive port and polish (valve guides were shaved down flush with head, only on the bottom side of the valve guide, didnt touch anywhere else)
- crower nonvtec cams (403's aka stage 2's)
- crower springs (street/strip) orange springs
- factory retinners
- factory valves

Now when i tryed running the motor for the first time, wouldnt start. I had almost no compression and had snapped piston rings and had piston slap and full nine. So anyway, back to the point of this thread in the first place. I took the Head off of the motor and it turns out my valve guides were pushed down a good quarter of an inch and i know this because when i was doing the porting and shaved them down myself almost flush. I relise that the valve guides being pushed down could of happen for a few different reasons but... what i want to know is, should i have modified the valve guides because of the lift on the cams being so high or can you run the crower 403's on a 100% factory head ?

Im aware that its a common thing to shave down or modify valve guides according to your cam profile but is it necessary for this set up, i didnt think it was but correct me if im wrong people...????