Posted by ken on October 21, 2003 at 18:18:48:
In Reply to: Re: Choosing inboard transmissions, How? posted by Colin on October 21, 2003 at 00:30:22:
: : Hello, I'm new to boating in general and want to build a Cracker Box with a transmission. I see differant ratios listed for BW Velvet Drives. We are using a 400+hp Ford 351W engine. How do I decide which ratio is best for my boat? 1:1, 1.91:1, 2.??:1. I hope this doesn't seem like a dumb question. I am an experianced automotive mechanic, and woodworker.
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: My research says for light boats, go for the 1:1 for faster prop speeds. The 1:1 has only a single shaft, therefore lighter and smaller as well. The 71c for big blocks, the 70c for small blocks.(Borg & Warner)
The 70c series BorgWarner was a early tranny that evolved into the 71c series. The 71 can be used on smallblock. The 72c series is a heavier version suitable for the bigblocks. VelvetDrive has a web site where you can see the power charts for their respective tranny's.