If you run an LT4 hotcam on 1.5 rockers, its specs are 218/227 .492/.492 112 LSA. If tuning is not an issue b/c I have a great tuner, can you run this cam in a 91 305 TBI with stock heads, better springs and new lifters? Car is an auto w/ 2500 B&M converter.

 

All the stock TBI heads I've seen have no more than about .470" clearance between the bottom of the retainer and top of the valve guide seal (some have considerably less than that). I wouldn't try it without some valve guide work first.

 

+1 on what ^ said. .470 is max for most. anyone know about how much $$ we are talking here concerning the machine work for the heads to accept higher lifts?

 

Well, the money to pull the heads,have them machined, and put them back on, and all the work isnt worth it. I am gonna use the 305 in something else after I swap an LT1 into my RS, and was gonna put that cam in it. I can get one $75 right now from a friend is why I was asking. I am going bigger witht he LT1's cam though, so not getting it for that motor.

 

oh no of course i was assuming doing the work all myself (i want to swap my headgaskets anyway), do some garage porting to the heads and have them machined for the lift if it pays off... that's why i was asking.

 

I was just saying it isnt worth it to me, however I would like to know roughly what it costs to machine the valve guides, in case I ever do need to know...guess it depends on the shop.

 

I got a quote to mill the valve guides and reassemble my heads, and adjust the springs for any nessecary shims per cam spec for $100