My brother is stubborn and will get this done. Formula F3 with 454 BBC thru Pre Alpha No. 1. He needs to use small bell housing and 12.75" Flywheel to make it work.

Is the flywheel he needs to use?

http://www.citycratemotors.com/scrip...product=324487

sprink,what year is your engine?

'87

I am also working on a similar project. I made a spacer plate 1 inch thick the same shape of the bell housing on the outside and cut the inside to fit my 454 fly wheel. I am replacing a 4cyl for the 454

I told him that I thought it would be simpler to go ahead and find a decent Alpha I inner plate...like they are every where and bolt it to the Pre Alpha outer. That way he could use the larger bell housing. His concern is that he would have to change the steering ram.....really?...this is a problem?

So what!!! I told him that he's swapping in a 454 in place of a 350...make it work...the steering rams are every where also!!

Having done a lot of engine swaps through the years ,I didn't know there was a 12.750 externally balanced flywheel readily available. I don't see why it won't work .A bellhousing would be the right way to do it but sometimes you gotta do what you gotta do. Are you going to be running thru transom exhaust.

sprnk,the flywheel in the link is the one you need.

Correct, thats a tough little part to find. Im a dealer for several different HP parts companies & City Chevrolet is the only place Ive seen that one at a good price. I looked & tried to save you a couple bucks. Sorry, best of luck!

I don't think you have the right one (in your link). That one is for a one piece seal and yours is a 1987 with a 2 piece seal. This one is also neutral balanced. Your Mark IV motor is externally balanced.
I went through this about a year ago matching a Mark IV 454 up with a Volvo Penta bellhousing.
Had to buy a Rhino 167531 flywheel and have it re-balanced for a 454. Take the new flywheel and any size 454 flywheel (or even a flex plate for an automatic transmission) to a balancer and tell them to match it. The new flywheel is only about 75 bucks but being they have to add weight, balancing will probably cost you twice that.



PS, make sure you tell them that it is for a boat and they don't have to worry about the clutch face. That way they can bolt weight to it and not have to use that super expensive metal.
GEN IV 1965-1990 (2pc seal), GEN V 1990-1995, and GEN VI in 1996

Been a while back but this place made me a flywheel for a specific application at a very reasonable price. Flywheel in link you provided won't work

www.innovationeng.com