yes use them, They act like a girdle helping to decrease block flex by holding the sides of the block in the center. I like them better then the mains I used pictured aboveHi . Have anyone with any success used these milodon main caps . I think i asked once before what the pro`s thought about them and the general idea was that one should get a race block if that kind of power is to come out of it, or cut off the outer parts of them and use them as two bolt caps and I`m fine with that. But it really did not answer the above question . Have they been used with any success.Best regards UbbeView attachment 1715449443