I guess the most important questions are:
- How fast do you want to go? Stoplight drags? Highway flyer?
How many ponies do you want? 120HP? 200HP?
How long do you want it to last? 10K? 100K?
And finally, how much do you want to pay? $3K? $7+K?
The suggested/recommended engine builders narrow down quite a bit as the above requirements become more specific. HP costs $$$, and so does longevity; lots of either isn't cheap. And don't be misled by hollow promises; find out who
really backs up their "talk" with a descent "walk."