your tie bar lifters from the crate engine should work with the earlier block with a normal base circle cam, you will not need the dogbones and spyder for this.
when you use the hyd lifters made for the dogbones and spyder you have to use a reduced base circle cam.
again, i could be wrong, have before.
i would use the vic jr off the crate engine for your 408 also unless you like the street stoplight to stoplight thing, then the rpm air gap would be the way to go, but kc will help you on the choice here.
before you split the heads and shortblock pm me a price and a seperate price also.