no mods needed on stock block---if you go solid go with Comp 829-16 it has a solid body no oil issues--do not use a banded lifter --if hyd 440 source has rollers lifters for $299 a set--GREAT deal compared to others that probably get them at the same place--that spring you have is usually a comp 928 if so it could be used with hyd roller depending on installed ht -- if you go with a solid be careful and don't over do it on pressure like you would on a racer--this will keep the rollers on the end of the lifter where they belong--street miles can KILL solid rollers with too much pressure and if you get a solid designed for street use it will have easier ramps and not require so much pressure anyway.