440 source sleath heads

Not sure how much better they will be ? What I can say is that my brother has a set but he used different locks I think springs and retainers as well ? He has a 030 383 284/484 edelbrock rpm 4speed 3.55 in a 70 Road Runner and it pulls really well. I think the heads will work well for the money. It pulls way harder then it did with stock heads.