have built many big blocks some of the block from gm had bad lifter bores they were off and would cause the cam to go out. so the break with light spring may help but if the block is off in the lifter bore this may not help. some lifters are better than others to if you tell me what is you seat psi is ? if it is 135 psi i would run it with the spring you have . i try to run all the big blocks i build with roller cams in them .but there are somethings that will help . get it to fire up no cranking.and run it at 2000 rpms. 1/2 hour. if soild cam you can sand the lifter feet with 600 wet dry sand paper or use the hy lube lifters they have a EDM hole thru the foot of the lifter so oil will be were you need it and helps at low rpms so oil will be on the cam lobe. i like the hard face lifers .this lifter has a hard lifter foot that is put on the lifter body . primeing the engine you should all ways do but you need to use a old dist body so oil will go thru the oil galley the dist will plug the big hole so oil will get to the top end and may help if it a hyd lifter engine have light oil in them so this still will help . molly work ok but you have to put it only on the the lobe and lifter foot not on the side of the lifters i use oil here. make sure you can turn them in the bores before you lube them. if this was done by your engine builder then you can not do much now . so if he wants to run it in with light springs in it and brake it in for you you may want to pay him to do this so the cam may have a chance. to brake in ?this is why i run roller cams after doing all this there is still a chance it will whipe with a soild cam