Hey guys I plan on converting my 440 to a roller cam. I will be doing a Bullet cam and was wondering about a upgrading the valve springs. I have Edelbrock heads but Im not sure about the valve springs.

I will probably get a matching spring set from Bullet.

Will I need to machine the heads for new springs?

Pretty modest cam 230/238 @ .50 .530/.530 lift

You can just add an inner and be AOK for cheap
I am guessing that is hyd roller
The hyd roller lifters being sold now are sensitive to spring pressure--on a hyd roller like one you indicated with the Morel lifters
145 set 340-350 open range is good, adding one of Comps inners will put you close at that lift-I forget the Comp number--call Todd at Marsh Performance --No head mods, drop on and go

Roller cam lobe profiles need a lot of valve spring pressurs to keep the rollers on the lobes at RPM, the higher the RPM the more spring pressures needed As already stated if your running a hydraulic roller use a set of sprins that will have 150 t0 200 lbs on teh seta sand at least 400 to 425 lbs over the nose, not any more than the cam company recommends I use springs that have at least 230 to 275 lbs on the seats and 600 Lbs. + over the nose, sometimes as high as 850 lbs over the nose, on the bigger solid roller lifter cams. the higher the shift RPM the more pressures needed to keep the roller from flying off the nose at RPM The old adgae of a little to much spring pressures on roller cams is just right