Thread: Difference between 3.5 and 4.6lt V8

Originally Posted by Chad

Actually in a P6 rover sedan, so going by the size of it may be a little lighter than the Ford,

I have a spare Auto I am having rebuilt, with custom internals and convertor.

I didn't read the first post properly. When I saw 3.5 to 4.6 I just assumed RR classic. Borg Warner 35 should be ok in the P6, but there is no way I would run one in a RR, even a 3.5.

Dave.

A Rover P6 has a mass in the order of 1300kg.

My P6 has been running a 4.6 litre engine since 2007. Has 78,000km on it now, no problems at all. The Borg Warner 35 transmission as it was originally is no where near strong enough, but can be upgraded to M-51 standards with Ford gears, servos, kevlar bands, heavy duty clutch pack. Mine runs higher line pressure too so the shifts are very firm and fast. I use the Rover torque converter without any problems. It has a stall speed of 2250rpm with the 3.5 so the 4.6 will just push it higher. If you drive the car with respect then the transmission etc is well up to the task.

You don't need to use kickdown or change back into second to overtake, the engine has sooo much torque it just stays in top and you accelerate like the old 3.5 would do in second.

Ron.

Would the Borg Warner 12 that is used in higher powered jags from the 70s fit - they are cheap and plentiful.

Garry

If my memory(not too good these days) serves me correctly, Jag's of the 70's had a Borg Warner 65.

Dave.

Jags from the 70s did indeed have the BW65, so did the P6 Rovers from mid 1974 onwards.

Some people are starting to fit ZF 2 HP22 transmissions into the P6, but it is not a straight fit. The tunnel needs modding, rear engine mount needs to be fabricated and the tailshaft might need shortening although not 100% on that one.

Ron.