That leak would get you to .320. I think after that you would still have to use the .340 system only sbf. I would really not attempt too much without a computer that you could use with the SBF right handy on them.... I do not think every store will do it for you, my two local stores they barely know how to turn on the phones and there response to EVERY problem is factory reset lol.... Might try it but I think with Rubix on the phone they might not wanna help too much hopefully they will for you.