If i plan on using a distribution block to run a 60 amp agu fuse for my 4 gauge and a 30 amp agu for my 10 gauge headunit lead, do i need to run a 90 amp fuse inline after the battery and before the distribution block? I've never used a fused distribution block before so i'm not sure.

Yes you do, the fuse is located within 18" of the battery to prevent the entire run of wire from catching fire. If it gets too much voltage it'll pop the fuse instead of burn the car down.

I'd run something higher then the other two added together - You want the inside ones to pop first if you are spliting the power. Also both fuses seem a little high - Most HU only need a 10 and for 2 w0 you will not need a 60.

Thanks, so the inline should be slightly larger. The 60 is probably to large but alpine and crutchfield reccommended a 20-30 amp fuse for the v-drive lead so im going with that. I already have it hooked up now with 2 seperate wires coming off the positive terminal but am looking to clean it up.

O I should of read your sig. I didn't see that you had one of Alpine'* High Output HU'*.

For the main inline fuse, always fuse at 80% of the rated capacity of the wire, within 2 feet of the battery.
A fuse on average will take 110% - 120% of what it is rated at to blow.
For example 100A fuse will blow at 110A - 120A instead of 100A.

4 Gauge wire is rated for 150A so I would fuse it at 120A or 130A.
All you are trying to do is fuse the main power cable so it cannot exceed its max rating. By fusing it with a smaller fuse you are just limiting your max power & your going to go through fuses like gasoline.

Fuse all other components off the PDB (Power Distribution Block) at the appropriate ratings.

Here is a helpful site and chart for wire gauge sizes & capacity:
Link: http://www.the12volt.com/info/recwirsz.asp

Instead of a inline fuse I would look at a Breaker it will end up saving you hastle of changing expensive fuses.

Hope this helps,

Dutch
MECP Certified & 310k Licensed,
Electronic Tech