1984 305 H.O. 700R4
I have stripped all smog and computer controls . I'm running a MSD HEI distributor and Holley 650DP carburetor. I have installed Flow Tech Header and true dual exhaust w/ Hushmasters.
I am unsure what lift and duration cam to use. Engine runs to good to warrant a rebuild and cant afford a set of heads at this point.

 

I did the exact thing with an Lg4 which shares the same heads as your L69. I believe I used a Summit K1103 kit best I remember and it dropped a second in quarter mile from my baseline putting it in the 14s. It would have done much better with some gears and higher stall torque converter but still hit in the high 14s. Much better than it was stock.

 

I think it would do well with the older Crane 260 or 272 or Comp high energy 260 or 268 cam. They don't need the same kind of spring pressure that the XE grinds require and are therefore less likely to wipe a lobe on todays oils.

 

With that much lift, did you have any problems with broken valve springs.

 

Nope. Its borderline with 466 lift on the exhaust side but it didn't give me any problems.