Quote:


I've heard that a cast crank just isn't going to cut it.


First of all, let's go back to square one when everybody else is running off in a 100 different directions like chickens with their heads cut off.
Your forged crank is going to cut it unless you're having someone build you a 600 hp engine that you're going to do 8k rpm test & tune runs on Friday nights.
Another case of a little knowledge is a dangerous thing.

Secondly, if you say "a cast crank just isn't going to cut it" because it won't accept a 4 speed, there's a simple work-a-round solution to that by machining off the the end of the tranny input shaft and using a special order bearing from NAPA or some other places.

Third, if you already have a forged crank, MOST likely it will accept a 4-speed. Simply look to see if there is a hole at the end of the crank. If not, see #2.

Finally if you have a forged crank with the hole, go to town with it.

The forged and the cast cranks each use different flywheels, btw.