Autocannon (well whatever benchmark its going to be the bench mark should be more £ than a missile cost as a blastmaster a blast template krak with pinning),+ bolter upped to flamer and
CCW=115
Blastmaster costs 40 off the rack and your making the flamer AP3.
Your saying those changes =5 points
I think your points might come down as you say for the actual items.. but your starting model costs needs to be way higher.. and then once you've perfectly balanced it you then need to add the imagination tax.. so that folks will be happy.
Twin linked sonic blaster arm? (on this dread as another option, instead of one of the above?) the assualt mode means nothing.. So its always going to be firing 3 shots.. yeah 10 points (a half way house to a heavy bolter due to the strength drop) seems fair.. Or consider it as an alternate upgrade for the twin linked bolter
(For X points you may make it a doom siren, for 10 points you may make it a sonic blaster (not twinlinked..you just get 2 more shots a turn out the thing.. and its slightly worse when your close up)
Basically if your making stuff up..always pitch higher rather than lower
Will it still be insane? If your removing the insanity rules.. remember that under the new codexs the reason our dreads are cheaper is because of that crappy rule.. so you'll need to bump it up some more if you ditch that.
hope it helps
KMB