To answer the question, I did this conversion.
My '75 914 started as a 1.8, then 2.0, then it went to a 3.0 SC motor. Now my 914 has a 3.2 Carrera motor. If you are going to convert a 4 to a 6, be prepared, it is not cheap if it is done correctly. Assuming you do it yourself, you will spent somewhere btwn 6 to 10k (maybe more) depending on what type of power plant you will have. This does not include the cost of the car. It is best to find someone’s abandoned project or buy a complete wrecked 911 and get the parts you need and sell the rest.
After seeing various 914s on the track, it is better to spend the money on tires, suspension, and brakes. The best money spent is money on track. There is no substitute for track time. Even with 250 + HP in my 914, there was a guy in a hot 2.0 914 at VIR who had much better lap times than I did. Though I had better brakes, suspension and HP, he had much more track time than I did. On a road course, there are many places where you do not need 200 + HP.
Not to say that having 250 + HP is not fun. It is BIG FUN
However, learning to drive a 914 on the track is more important than having a big HP motor. Too many folks muscle their way around the track, never learning the smooth line.
Other things to keep in mind, once you get above 120 + MPH, 914s get awfully twitchy. I will have to add some additional spoilers etc to handle that kind of speed. Also, I only have 205 x 16 tires. I must flare my car so that it will not spin the tires coming out of every corner. Also, with that much HP, you must reinforce the car, either with a cage or a stiffening kit. Oh, and one day, I plan to have a LSD in the tranny.
And as all ways, just my $0.015 worth
[This message has been edited by Jim Smolka (edited 04-22-2001).]
[This message has been edited by Jim Smolka (edited 04-22-2001).]