B27 is the PRV. It is the early oddfire version.
They are a 90 degree V6, which means the firing intervals are not even. If you look in the dizzy you will see 3 bunches of 2 firing points.
Later ones like the B280 are evenfire, and have the crank journals split to give an even firing pattern.
Oddfire ones sound better, a bit like a V6 made from 3 Harley motors. A little off beat and woofly.
Check the oil has been changed regularly. They have a fairly narrow oil gallery in the head and if it cruds up then the flow to the cam and timing chain tensioner is low and tehy wear fairly quickly. One good mod is to open up the restrictive hole a little, and shim the oil pump to increase pressure and flow.
You should really change the oil at 3,000 mile intervals and you will get a long and happy life from the motor.
Have a listen to the bearings in the bottom end. these sometimes get rumbly.
Don't cook it as the head gasket will blow.
If the gasket does blow and you fix it, it will probably blow again soon or the liner seals ( it is a wet sleeve liner engine) will go, so it is good to do an overhaul with all new seals and gaskets if the head gasket blows. This is also a good opportunity to replace the timing chain tensioner as a precaution.
Tranny is the good old Borg Warner 55 slush-o-matic on most cars, 3 speed, fairly rugged. If you get a manual one, an early one will have a gearbox unique to the 260s in 4 or 5 speed, but a later one will have an M46. Bellhousings for a V6 are like gold dust. Otherwise conversion should be a piece of cake.
The V6 can be tuned quite a bit, and responds well to boosting. There were Peugeot LeMans racers putting out 400hp using the same standard block and crank.
They are real nice to drive, quite torquey.
Go for it if it is any good.