Volvo 270B vs. 270A ????????

[kjly63]

I am currentely running a 270B drive on a 19' Cig with 350 Chvy. RPM's are high at 5400 with a Volvo Ultra 24" LH SS prop. I bought a spare drive that came off an early 70's Chris Craft also with a 350 chvy and just noticed it is an "A" drive.
Anyone know what the difference in gear ratio is? and any idea how mant RPM's would drop runiing this drive insted? :cartman:

Any idea's or comments?
Ken

[Mr X]

I am currentely running a 270B drive on a 19' Cig with 350 Chvy. RPM's are high at 5400 with a Volvo Ultra 24" LH SS prop. I bought a spare drive that came off an early 70's Chris Craft also with a 350 chvy and just noticed it is an "A" drive.
Anyone know what the difference in gear ratio is? and any idea how mant RPM's would drop runiing this drive insted? :cartman:

Any idea's or comments?
Ken

270B=1.61:1
270A=1.35:1
Easy math now with a calculator

[MOP]

That will open up your prop options, there are a lot more lower pitched cheaper props available.

Phil

[mattyboy]

That will open up your prop options, there are a lot more lower pitched cheaper props available.

Phil


ok kenny I'll trade ya heads up my 21 spinelli for your 25 cleaver ;)
kenny I'll try and find the speed calculator and email it to you

[mattyboy]

here ya go
http://go-fast.com/prop_slip.htm

[penbroke]

:cool: Nice find! I don't think there are too many of those around.

Frank