V4 Crossflow lower unit interchange

**LakeFever** · 08-13-2020, 09:35 AM

I read that the V4 looper lowers are 15 spline same as the V6. Are these a direct bolt in to a crossflow? If not what do I need to do to swap one in?

**SS Minnow** · 08-13-2020, 09:52 AM

Some of the V-4 loopers are 15 spline, but not all of them. I think most of them were actually 13. I have a 1990 140 V-4 and it is 13.

As far as if they fit a crossflow, sorry, I do not know.

**LakeFever** · 08-13-2020, 10:08 AM

Ya me neither Im pretty clueless to parts swapping these OMC's around

**nitro_rat** · 08-13-2020, 11:21 AM

i've never done it but i think they will swap. You may need to change the upper driveshaft, idk. the bolt pattern of the lower unit to the mid is the same.

**LakeFever** · 08-13-2020, 01:04 PM

I did find some info saying similar and there are apparently a lot of different factory configs but apparently on the small spline looper lowers the bolt pattern is the same and the drive shaft is often too long which may need a trim and the stock crossflow shift rod has to be re-used. The larger spline V4 gear case I still have zero clue on compatibility

**keefallan** · 08-13-2020, 03:02 PM

It surprises me that the driveshaft would be too long. Yes, the shift rod would have to be used based on the intake you have. I have a curved rod and a striaght rod for two different years...........same motor, different intakes and how the shift rods attach.

**Paul Vaillancourt** · 08-15-2020, 09:14 AM

I cannot remember exactly what year but the drive shafts got longer i think in the late 1980's.
I have run one with the shorter shaft length for a short time on a motor that came with the longer drive shaft but i do not think it would be a good idea for long term usage.
The loopers had a different shift shaft from the crossflows but changing that would make it usable.

Originally Posted by keefallan

It surprises me that the driveshaft would be too long. Yes, the shift rod would have to be used based on the intake you have. I have a curved rod and a striaght rod for two different years...........same motor, different intakes and how the shift rods attach.

**powerabout** · 08-15-2020, 09:17 AM

first year v4 had the v6 lower with special ratio
was before 2 piece driveshafts
yes people use them to get 15 spline shaft and v6 ratios

**perfmarine1** · 08-15-2020, 11:00 AM

Originally Posted by Paul Vaillancourt

I cannot remember exactly what year but the drive shafts got longer i think in the late 1980's.
I have run one with the shorter shaft length for a short time on a motor that came with the longer drive shaft but i do not think it would be a good idea for long term usage.
The loopers had a different shift shaft from the crossflows but changing that would make it usable.

I thought it was 92-93