Rover engine types help please

truckdoctor · Post by **truckdoctor** » Wed Jul 02, 2014 6:04 pm

Currently I have an p6 engine in my P5B and am currently looking for more power. Looking at ebay reveals Rover 3.9 4.0 4.6 engines available.
Seems a bit confusing to me so, as an example could I fit the 4.6 engine and make it look externally like the original or is it completely different.
If so what is my best option?
Thanks, Steve

mgbv8 · Post by **mgbv8** » Wed Jul 02, 2014 6:55 pm

Apart from some extra bolts in the side of the block low down near the sump, the later engines will look no different

Which is great if you are building a sleeper eh

truckdoctor · Post by **truckdoctor** » Wed Jul 02, 2014 7:02 pm

Well that's exactly what the plan is, any idea what power would be expected by using the 4.0 engine and running it on carbs and a mild cam?
and the same with the 4.6?

mgbv8 · Post by **mgbv8** » Wed Jul 02, 2014 7:25 pm

Some of the other boys are better versed in what to get from a nasp tuned RV8 mate. I've never built one. I always knock the nasp tune out of my engines by lowering CR for boost. I run bigger ring gaps as well.

If you use the 4.6 heads and a decent cam I dont see why you should not make 220-230 for a mild tune on a carb. But you can play with pistons and CR + cams etc and could squeeze 260 out of it?

The best thing about the bigger engines is the low rpm torque you can achieve.