Volvo-Penta 270/280 Interchangable??

[triumph66]

Hello... I have a 1985 5.7 (350-Chevy) Volvo Penta with a AQ280 outdrive. We recently had a bad storm and the lower unit cavitation/exhaust ears got beat up pretty bad and is now missing a few chunks out of it. It still seems to be running fine (although I have not taken it out.... just shifted in and out of gear).
Without doing any research I bought a 270 outdrive for a V-8 chevy that is in "like new" condition. After making the purchase I realized that There MAY be an interchangablity problem.

Anyone have any thoughts, input or advice for this change??????

All advice and suggestions is GREATLY appreciated!!!

THANKS!!!

[tuantom]

I switched from a 270 to a 280 drive and it was just bolt up. Are you switching the entire drive, or just the lower gearcase?

The only issue you may run into is shaft length. There were short or long hub drives. I think all the 1.61 ratio 280's had long hubs - not sure if all v-8 270's did. I've heard that if you have a short hub drive, you can tap the end of the shaft to accept a bolt - this will allow you to use your long hub prop on a short shaft. Maybe someone else can back this up.

[triumph66]

Originally Posted by tuantom

I switched from a 270 to a 280 drive and it was just bolt up. Are you switching the entire drive, or just the lower gearcase?

The only issue you may run into is shaft length. There were short or long hub drives. I think all the 1.61 ratio 280's had long hubs - not sure if all v-8 270's did. I've heard that if you have a short hub drive, you can tap the end of the shaft to accept a bolt - this will allow you to use your long hub prop on a short shaft. Maybe someone else can back this up.

Hi tuantom.... thank you for your reply! I bought a COMPLETE outdrive minus the square plate that mounts between the outdrive and the hull of the boat. I PLAN to change the complete outdrive simply because I think my cone clutches are going bad.

So... First of all, I need to know if the drive will work and mount up to my exisiting (for lack of a better term) hull mount plate.

Second... I have a brand new prop that I didn't even get a chance to put on. It is a LH rotation 15" X 19" long shaft Propeller. Will this work??

The replacement 270 outdrive was delivered by UPS yesterday. I have not had a chance to open the crate yet.

Thanks for looking at my post... I appreciate all input!!!!!

Best wishes,
triumph66

[eddiepitt]

Will the 270 lower match 280 top, will 280 top replace 270 top for installation

[Waukesha Volvo]

Tuantom, does the 280 case give any performance difference, compared to the 270?

[tuantom]

They have the same gear ratios - so it'll probably be minimal.

However, the 270 does have that big fat exhaust port/steering trim rudder - and I'd think anything attached to the boat in the prop's thrust can't be too good.
But that was never an issue on my setup since my exhaust exited through the transom instead of the outdrive - and that stock exhaust port was replaced with a slim steering fin - much like the 280's.