I am planning on installing a large h-bird graph on my 06 i class...i have found the necessary brackets to install this on the dash...my problem is I have an lms 520 in the dash..it is the only way I can read depth while on the pad..thought about moving it to the side but can't find a bracket for it...I also have a 998 but can't find a shoot through the hull ducer for it...any of you graph wizards out there can give some advice...is there a new lowrance graph out there that will work on this existing through hull transducer...

The shoot-thru for the 998 is the XP 9 20. It is a 83/200 kHz transducer---- VERY common.
Just need the 9 M SIDB Y cable to connect it and the SI transducer to the display.

What is the "large Humminbird graph"?

You can also convert the Lowrance transducer to work with the Humminbird with the Motor Guide 8M4001912 cable.

Thanks Wayne...I figured there was someone on here that had the answers to help me out...planning on a helix 12 on the dash...so if I use this motorguide cable it will plug in where the 998 si transducer plugs in and I can remove the si transducer from the back of the boat..

Yes you can use the 998 as a 2D sonar/GPS unit by changing the Connected Transducer setting to Dual Beam and just have the shoot-thru connected. That cable is the Motor Guide to Humminbird 7-pin adapter.

If you don't want mapping/GPS just don't connect the GPS antenna to it.

Any idea where I might pick this cable at..