The link 70AARCuda posted has a solid build that is going good behind a 600hp SB at 3400#.

The black magic that builders try to sell you is BS. Get a video and book and build them yourself. Easier to do than an engine! Most all the parts anyone sells are nothing but reboxed/packaged parts you can buy from anywhere. It's a blast when you pay 2-3x for a set of teflon seals and they come in a bag with the same part number you can buy elsewhere for a bunch less. Makco/bulkpart and WIT are good sources.

Anyone that tries to sell you an alum drum for a 904 because of explosion risk, run forest run

Shop smart!