How much hp should I expect to gain with a chip?

[rodpaine]

Here's my write-up on the chip testing I did back in 2004, including my dyno results with the Mark D chip. I've been running this chip ever since and have another Mark D custom chip, for use in a MM cylinder head, but still haven't gotten to it yet.
FWIW,
-Rod

[TobyB]

But doesn't the tune delete if the battery ever disconnects / dies on your car?

EPROM. Not gonna happen.

t