Help...

[need4speed]

Im building a 4.6 engine based on a 3.9 block. Due to the engine being used in a landrover i intend to run an electric winch, and hence run a dual battery setup with high output alternator. Now the trouble is unless i use a serpentine belt system, i cannot use a 200amp alternator (due too belt slip). What do i have to buy/fit in order to use a serpentine system on my old 3.9 block?

[The Original Tom]

A timging cover/water pump from a 4.6/4.0, a new crank pulley (not sure if shaf size is the same), and a new PAS pump/pulley, (aircon?)
With the new timing cover will be needed a new oil pump.
Or you could just get an SD1 style alternator bracket, and a rangey style one, then you could fit 2 smaller alternators? (only possible if you've not got A/C)
You might need to weld a new pulley onto the water pump to drive it though, and shim one f the brackets, but it would be cheaper, if not easier than getting a whole new front-end set up.

Tom.

[katanaman]

If you use a 4.0-4.6 front cover you will have to get a whole new ignition system as there isn't any provision for a distributor. You would be better tracking down a 3.9 intermediate front cover if you don't want to do that as that cover has the serp stuff but still uses a distributor. I am assuming your using a 4.6 crank machined to fit the older block?

[x.l.r.8]

I'd second the dual alternator route, underdrive the secondary one as you will not be hammering the winch all the time, very cheap and you will be able to use any battery rather than matching pair (if you are running a true dual battery system), we used to do this in the early days of car stereos and is was a reliable way of running an extra battery while ensuring that you always have a good battery to drive home on.