I have a 1990 NA that I'm going to convert to a V8. I want an aluminum engine with about 400 rwhp (to start), OBDII controls and decent fuel economy. Looks like the LSX is the way to go.

I'm a "Ford guy" so I know my way around small block Fords but know next to nothing about the GM LS series engines, except what I have read on this forum and LS1 Tech in the last month or so.

I have a few questions and would appreciate the help of the experienced LSX Miata guys.

1) Which LS should I go with to hit my 400rwhp target and not spend over $1,500 for the whole engine set up. (used long block, intake, accessories, ECU)

2) Is the above budget realistic? If not what should I reasonably expect to spend. I have seen recent posts of guys buying L33's for under $500. I have access to a reasonably priced machine shop and enjoy building engines.

3) I have a great deal of mechanical experience and I'm not afraid of welding, though my skills are rudimentary at best, which of the LS kits (Boss frog, Flying Miata, others?) are the most cost effective?

4) Is there enough info out there for me to fabricate this stuff myself without spending hundreds of hours reinventing the wheel?

5) I read about 30+ MPG with these LS Miatas. Is that for real?

6) Which dif set up is the most cost effective (expecting aprox. 400 lb-ft of torque) Ford 7.5, 8.8, Gertrag?

7) Anybody want to talk me out of the whole crazy idea

I would appreciate comments from any poster but especially the guys that have already done an LSX conversion.