what exactly do i have to get machined/done to my heads to get them to accept .500 lift? i kinda want to runt he lt4 cam but its lift is too much for alot of heads i look at so i figure i might as well just get my old 65cc heads machined or what not for it

 

Well you can run into two problems. Most of the time they say they cant go past that lift is due to the valve springs being too weak. Another problem could be the valve to pistion clearence. I am willing to bet that the reason they have the .500 lift restriction is due to springs.

 

cool, i figured that but i thought i might have to get some machine work done as well

 

No, that's not it at all.

It's due to the retainer hitting the guide boss. With any type of cam below a .700" solid roller above 260* duration @.050", you will not have valve to piston interference.

The springs are weak, but just about any 1.25" OD springs (including stock) won't hit coil bind until .550 -.600" lift. Usually coil bind is at 1.2" and it'll be set at 1.8" for the installed height. 1.8-1.2=.600".

You need to grind/machine down the guide boss. You can use a feeler gauge to tell how much you need to machine down. Keep in mind those 187 TBI heads suck anyway so...