I shoot Mission X3, it is set at 70lb's with a 29 inch draw.
On my bow I have an S coil stabilizer,an ultra rest drop away and copper john deadnuts 3 pin.
My arrows are 29 inch Beman Black max 400's, i have white nocks, three white blazers and a 3 1/2 inch white wrap. Also my broadhead of choice it the MX-4.At the shop when i bought my bow I had the guy Chrono it. At the time I had the same arrows except they werent wrapped. he said I was shooting a 418 grain arrow at 288fps.

I can cut atleast 1 1/2 inches off my arrows, would this help or hurt?

Just my opinion-

all sounds great but when you say you can cut off 1 1/2" where does that put your insert at full draw? are you turning the drop away into an overdraw when you cut that much off of them?

418 going 288 for a 29" draw is some great speed. If speed is your only concern I'd leave it alone.
Now if your spine is acting weak ( a 400 spine in your specs, you're borderline) then cutting some length off MIGHT stiffen them up the amount needed to bring them in.

Are the broadheads grouping well at your personall shot distance limit?
If so, leave well enough alone, if not- time to make it so (could be any number of tweaks to make this happen)

It is going plenty fast for me and my broadheads do group pretty well, its just I was wondering about my spine of my arrows really, i was thinking that if I cut them shorter it would stiffen them up. As far as using the dropaway for an over draw, not really, But I think I am going to leave everything alone. It shoots good,most of my problem is me and not my set up...

Your setup sounds good. You could take 1/2" off your arrows. I don't like having the broadhead behind my hand....just in case it ever falls off.

Sound like you are getting good speeds...If you think you are shooting good...I would leave it alone.

10-4, if your broadheads are flying true then it's time to pick a tree and get the wind right- spine concerns are a thing of the past at this point.

Good luck this season!