Quote Originally Posted by 04lss View Post
whats a realistic expectation for gains on a stock car switching to e85?
About the same as running a tank full of race fuel (100+ octane) every time. You'll kill any knock you have so you'll gain back any timing lost from that.
The best part about running E85 is that you can drop pulley sizes. If you're stock, then you're missing half the point.

Get some headers or at least a downpipe and plog, an MPS, and switch to E85. Then you'll be in business.