Thread: 3.9 V8, next step to find some cheap extra power?

I think first step, if you are sure the cam hasn't been replaced or upgraded, would be the cam. Along with that I would upgrade/work the heads.

You can squeeze some power out of these engines but it'll never be that much compared to some of the more common V8's going around.

It'll depend on how much you wanna spend in the end. Some people go nuts on rover V8's trying to get to 400-500HP when some engines are available like that off the shelf for half the price.

Having said that I like the rover V8 and it is a bit of a talking point, sometimes, with other lesser 4WD owners who always want to know "what's under the bonnet?"

Good luck. Always wanted a V8 90.

What do you use it for?

In other words, do you want more HP or more torque?

Regards
Max P

High torque cam, stage 1 heads with matched manifold porting, decent dissy with custom advance curve, Ford 302 injectors (or Gen 111), if you can afford it a Mark Adams custom chip - should get you over 200 bhp and around 220 ftlb.

Or you could just swap in a HC 4.6 block and use your existing heads which will produce around the same in standard guise, but a new block would cost more of course.

Wolf3D engine management, i think standard cam (loads of the receipts and nothing that says new cam)

IMHO the next step if you haven't already , is to book some dyno time to tune the injection/timing to the optimum.
The 3.9 responds well to timing and can take a lot more advance than stock.
I gained 7% across the board with home done head mods following correct theory, ie most work on the valve bowls, short guides, taking the long sides out, and broadening around the valve guides. Lots of work on the exhaust valve pockets as the 3.9 heads look to have slipped in the mold, or the mold was old. Match the ports to the inlet and also take out the inlet mouth as far as possible and grind down the injector boss.

You can also gain a noticeable bit by blending the step into the throttle body from the rubber tube.

I don't know about cams. I have been chicken and stayed with the stock 3.9 cam. It is such a ***** of a job to change cams that I have stayed with it even with my Thor manifold , where a towing cam would probably help.
You are pushing it a bit ( to get practical low rev extra power) as the inlet manifold has short runners as it was originally designed for the Vitesse SD1 racing cars , so is biased toward high revs.
Those would be my first steps, but of course a 4.6 is the best with 15% capacity increase should translate to 15% more power if the valves, inlet etc can feed enough air.
Regards Philip A

Thanks for all the replies!

The car is my weekend toy, camping trips, off roading, a few pay and play days etc so torque would be the main goal.

Looking like;
* high torque cam (tighe cams seem like the place to go in Brsbane)
Tighe Cams Profiles,

* injectors (Ford 302 or bosch Gen 111)

*head work - new heads or work on standard? can it be a DIY job if enough time/care is taken over it or is it worth the cash to save all the effort just to buy new? Any recomendations on what to buy if new? Also any pointers to a good tutorial/build thread for DIY?

Then a trip to the dyno to get it retuned. It is running a very rich tune at the moment so could do with a remap anyway.

If I later decide i want/need more power then i can look at changing the block for a 4.6.

Also, does anyone know a part number for the ford or bosch injectors?

Try a set of these heads....
Cylinder Heads - Triumph Rover Spares South Australia

Make sure you are sitting down when you read the price

Originally Posted by vogue

Try a set of these heads....
Cylinder Heads - Triumph Rover Spares South Australia

Make sure you are sitting down when you read the price

"Only $5900 a pair" lol

I think I will go down the path of the DIY head improvements.

Now to find a set of 2nd hand V8 heads so i can take my time and do it properly without the temptation to rush to get the car back on the road!

Anyone happen to have a set sitting around?