How to adjust leaf spring rc?

[trikesrule]

Hi guys I've spoken of this car before it's a 81 Corolla used in Speedway (clay). Struts up front leaf springs out back. Now these things roll over quite regularly. When they go it's the LR going over the RF. I thought if I just raise the roll centres problem solved. Ok how do I do that and remain within the rules. Rules state no lowering blocks. Everything must remain visually std including the pick up points. So I looked at the problem the other way drastically lower the LR plus go a bit lower in the LF. It's still our off season for another 6 weeks............What are your thoughts guys anybody got any ways of raising the rear RC? I'd preferr to go this way cause when they have no suspension in the LR they tend to skip around and this car has a 12 yo (girl) driver.