So I went through this same thing a while back.

The best option if you have the money to spend is to get a set of aftermarket shocks valved and sprung for your weight and bike.

The option that I went with since I don't have the $600+ to spend on my project bike, at this point. was getting a set of YFZ450 front shocks. These are NOT a direct bolt on. The length is the same as OEM or close enough, and the lower eyelet will fit in OEM 87+ a arms. The problem is that you have to knock down the top eyelet on the shock quite a bit for it to fit in the upper mount. I used a hack saw then a big file to smooth it out. Also make sure that the Aluminum surround is narrower then the Steel bearing. You want that bearing to make contact to your frame, not the aluminum.

Also these are still not 100% ideal since they are for a different bike all together. They are worlds better then worn out OEM pogo sticks but not the best.

TRX450 shocks are too long
LTZ 400 shocks same length as trx450 shocks
400ex Also too long.

Banshee shocks are probably the same length as YFZs they just are not as good.

If you want to see this set up take a look at my Picture, I also have some posted up in the gallery. Hope this helps.