seat lifting

[seabag]

I have cruised the board looking for the information regarding seat lifting; have found this in scattered places.

The specs that I have found:
40mm long bolts w. 12mm heads; they are a JISC standard. Should these be something bought at a parts store as they exceed what is available at the hardware store?

Blocks: 3/4" The only thing I have handy is hardwood, ash and they seem to need to be about 40mm x 40 mm with the top corner of the front ones cut off because of the seat angle. Delrin would be my other choice but I don't have any bits handy. Any thing else work? 1/2 inch pvc pipe?

Getting the seat bolts out:
The front come out easily. The back not so, as it is hard to swing a wrench. I have to escalate tools. Does this need an impact driver? Other success stories?

Thanks

[tadpole]

bolts are 10mmx1.25x40mm rear, 8mmx1.25x40mm front. Use impact driver to break the threadlock. 3/4" hardwood works fine. Front blocks must contain the correct angle, all holes should be elongated for good installation. Send me a FAX # and I will FAX you a pattern.