The only difference is the old flat for left over from the 356 days. The 912 was meant to be the transition model between the 356 and the newer 911. The engine is a good 5 inches shorter and lighter so weight is better distributed. Most of us rebuild the four with larger P/C's and high compression. Good for about 65 hp/ltr. When the thing only weighs 2095lbs. they are alot of fun.
