Unfortunately, the 85-86 motors are limited when it comes to aftermarket parts.
Porting, larger carb, and pipe will make a difference.

However, due to the small intake it has it's limitations.

Don't get me wrong, you can make it run pretty good!
I did a 8mm "Long Rod" not a "Stroker" mod on mine and it runs very well and is reliable.

I did the mods myself so, it saved me the shop service labor.
Good Luck!

Joe