The V8 Owners Forum -

While I've been laid up with a nasty cold over the holiday period I've been doing a lot of reading up on previous posts looking for any ideas to squeeze a little more power/grunt from the 3.9 motor in my (fairly light) Cobra rep'.

One favoured way of getting more power seems to be to remove the motor from the car and replace with a GM LS engine. I have thought of that in the past but been a bit put off by the thought of having to replace the gearbox and propshaft as well as the modifications to the chassis for the gearbox. But then I had a thought. Can I sit my R380 box behind an LS motor?
I did a bit of searching and found some pointers to kit which would possibly help (www.marks4wd.com for instance) but I'm not sure this is what I require (or all that I require) and not exactly cheap either. I was thinking along the lines of a getting a suitable LS bell-housing and Rover 2WD bell housing (or making a copy of the rear end), cutting the back end of the GM one and grafting the rear end of the Rover item on at the appropriate position.
Then I need to locate a clutch whch will fit onto the R380 input shaft and graft onto a GM flywheel.

I'm sure it won't be as easy as I've made it sound but certainly seems do-able. Has anyone done this or more importantly tried it and find it doesn't work and could offer advice?

i nearly went that route but went this route instead,
Supercharger

https://www.marks4wd.com/engine-convers ... 410g3.html

$1100 to bolt an R380/LT77 to an LS? Yikes! Add in engine, ecu, mounts, changes to chassis, cooling, induction etc it sounds like a ton of expensive work.

When I wasn't happy with the power from my 3.5, I just hoiked it out and dropped a 4.3 in.

It boils down to what power you want compared to how much money/time/talent you have.

Scudderfish is on the right track, I think. Find a MOT failed Range Rover P38 and pull the motor out, give it top hat liners and new bearings etc and with whatever head work you do, you will have a much stronger engine than your present one and probably still come in costing less, too.
The Rover engines have the same bolt patterns from the 3.5 up, so you won't be faffing about with adapters and all that nausea.

I would suggest the option of doing it yourself if you are hell bent on the LS motor. That adapter from your link probably won't work because the 4WD boxes are different to the 2WD ones, the input shafts are different lengths, hence the spacer plate.
If you are capable of measuring accurately, you can mock the R380 up to the LS and calculate what you need to add to the bellhousing to make it fit, then draw up the bolt patterns to mate to the LS and have it water jet cut. There is a member on here that can do that for you, so you will be keeping it in the family, as it were.
IF you need to remove material to make it work, then you are entering a world of costs.
All the bolt patterns are on the interweb, so if you feel like a rummage around while your snot dries up, you can start there.

I doubt that R380 box would survive behind a LS engine.

Thanks for the comments guys. I must admit the "sanity" I was looking to check was whether this swap is possible (and if it's been done then plagiarise where possible) rather than whether I should do it - That's probably never going to be sane!

It is going to be a slow burner in any case, next winter's mod' if it happens at all. For this year I'm going to swap the heads, inlet manifold and trumpet base for some (hopefully) better items I have knocking around and also add ECU controlled ignition but I don't intend to do any work over and above that with the Rover engine. If I did then supercharging has got to be the way to go otherwise it seems like I'd have to throw a lot of money at the Rover engine to get significant power increases. At the end of the day I'd still end up with a Rover powered car which doesn't carry the same value as a large capacity US motor (in this type of car)

Perhaps I'm better accepting I've reached the end of the line with this platform at put my efforts into something else.

Coops wrote: ↑Tue Jan 02, 2018 6:38 pm i nearly went that route but went this route instead,
Supercharger

19466285_1722385737776194_8102319970200080818_o.jpg

Hi Coops, that's a really nice installation you have there, as I've been trawling throught the forum over the past week or so I've seen that a number of times, I also seem to recall reading some posts from yourself regarding the R380 gearbox swap when I was doing that last year - thanks for the help on that. Not sure thats practical for me though, don't even know if I'd have the space under the bonnet on my car.

Charger sits no higher than the alternator mate

Coops wrote: ↑Wed Jan 03, 2018 8:23 am Charger sits no higher than the alternator mate

Yeah, wasn't really clear about that, don't really mean the height under bonnet, more the overall amount of space around the engine, although I know of at least one guy with the same car who has a supercharger (looks similar to yours) on an LS engine. So probably is do-able.
Still looks like a lot of work though, every credit for assembling that. Looks OEM as well.

You could always say it's a TVR V8, that's got to be worth at least another 50bhp

Personally, I _really_ like Coops idea. LS in a Cobra is not unusual, supercharging your engine would be and it has the least impact on the rest of the car.

scudderfish wrote: ↑Wed Jan 03, 2018 1:33 pm You could always say it's a TVR V8, that's got to be worth at least another 50bhp

Welll that's another issue! I'm struggling to work out if it's a Trevor or a Morgan engine as it has both numbers stamped on the block. Maybe it's neither.

scudderfish wrote: ↑Wed Jan 03, 2018 1:33 pm Personally, I _really_ like Coops idea. LS in a Cobra is not unusual, supercharging your engine would be and it has the least impact on the rest of the car.

I do too but don't think I'd have the time to do it or the money to do it with. I'll stick with my plan for this year of getting the best I can with what I've already got around and worry about the next move after that.

Wi have a Dax GT40 that came out the factory in. 1990 with a factory supplied motor.

The numbers traced it to Morgan, who I believe did a deal with DAX to supply said engines.

Ian

The rotrex charger is a bolt on kit and can be done in a day quite easily, as its made for the TVR owner,

We are getting ready for our next stage which is a procharger D1SC to see how much further we can push this rv8 engine

Coops wrote: ↑Wed Jan 03, 2018 7:45 pm The rotrex charger is a bolt on kit and can be done in a day quite easily, as its made for the TVR owner,

We are getting ready for our next stage which is a procharger D1SC to see how much further we can push this rv8 engine

You've got me interested now! Been looking at the SC site and it is looking more interesting. Presumably I'm going to have to run MS or similar, don't think Hot wire can handle FI (at least not for elevated levels of boost. My engine is currently not serp although that is something I've considered (mainly because I think it looks better/mor modern) although I currently only drive the alternator and water pump (and have considered changing that the electric

What about internal engine changes? Surely I'm going to have to lower the CR? Any ideas on price?