Mitch!!!

Stroking that thing is a great idea, lot's of upsides:

1. Cubic inches eat up porting. I'd just leave your heads as is and see how they respond.
2. More torque means you will have more forgiveness in the powerband which will be a huge plus in your "point and shoot" Autocross.
3. You won't have to rev it as high, you can probably go with 3.08's or 2.94. 1,000 to 5,000 rpm range sound ok to you?
4. Lot's of low-end grunt coming out of a corner is intoxicating.

There are other kits to look at: the Hughes 426, and Rod Bloomer on here can get you into a 4.25" that will get you close to 440".