GTD Engine/gearbox Lowering

Hi all

I've just been reading with interest all the various options on lowering the engine in a GTD.... inverting gearboxes/Southern GT rear end/angle grinder to GTD chassis etc etc. The chassis is completely standard GTD and I'd like to lower the engine/gearbox by a modest amount c.30mm or so with the minimum amount of hacking and welding... this will bring my 8" deep Canton sump to within 5mm of the bottom of the lower chassis rail. Apart from the slightly improved CoG it will allow me to use a spacer/heat shield between the inlet manifold and carb to try and stop the fuel boiling and will also allow more space between rocker covers and rear deck for bigger breathers. I should say that I have a Renault 21 turbo box. It would appear that the chassis rail below the gearbox needs the most alteration. I realise that this is a sort of 'half way house' mod and undoubtedly the SGT rear end is the way to go, but that is not feasible right now.If anyone has done this or has ideas on how to go about it, then please let me know!

Cheers, Dave

Mike Pass

I don't have any fuel boiling issues on my GTD. you may be using a sledgehammer to crack a walnut. I would look at a lower inlet manifold or better under rear clip cooling or a thin insulating spacer under the carb or a 12v fan to blow cool air over the carb when stationary. I have a Performer RPM inlet manifold and a Holley with a drop base filter. I have the nine hole panel over the carb.

Brian Magee

Hi Dave,
You can take out the engine cradle and make new mounts that bolt to the chassis rails either side. That gets rid of the rail under the sump, then you can lower the front of the engine to the height you require. You should also be able to replace the gearbox rubber mounts for ones half the height to drop the back slightly.

Hi David,
When I was building my Tornado, it originally had a Rover engine, which was swopped for a Ford 302, I positioned it so that the Moroso 8” sump was level with the bottom of the chassis. However I have a Chris Cole bellhousing (which takes the full-size Mustang flywheel) and this is the lowest part of the vehicle. New crossmembers were fabricated and there are a few photos in my build log (Norfolk Tornado) on pages 1 & 2
Hope this helps
Whilst I haven't (still) finished my GTD, I opted for the SGT option early on in my build, especially as I was using an Audi box. I also had a set of the Roy Smart engine mounts instead of standard GTD.

See the removal and replacement here: Brett's RS GTD

The most I have lowered a standard GTD ENGINE UNIT is 80 mm, this is using a Canton 7.5 inch wet sump pan ( of course I have lowered a dry sump unit in a GTD more but that's a different story ) This allows for the Canton sump to be 40mm BELOW the chassis rail. I was a bit nervous of this first time, so for a first time out on the Isle of Man Three Hills competition I added a strong sump guard under the sump, just in case. After the event on some very unforgiving roads there was not a mark on the guard, so of it came and we ran without it for many years in all sorts of events. How brave are you ?
Cheers everyone for the replies......
Mike, a small insulating spacer might do the trick but I still only have room for 'tiny' valve cover breathers and would also like the benefit of a lower CoG.
Hi Brian, hope you're all well. We already did that....remember! Roy Smart engine mounts and small bobbins for the gearbox mounts - works well and engine level but if I can drop it another 30mm relatively easily that would be great.
Andy, could you possibly give me some detail on the chassis mods you made - from the photos it looks like you moved the brace below the gearbox to below the rest of the chassis making it the lowest point - have I got this right?!
Brett, I'd love to go the SGT route but right now it's not an option.
Hi Frank......not that brave!!! If I could lower the engine/gearbox c. 30mm that would get the sump level with the chassis rail. Can you help please with any ideas on how to achieve this.
Thanks for all your help.
If you want to do it easily with a minimum of fuss I,ve got a pair of Roy Smarts bolt-on engine lowering mounts for free. Uses existing bolt holes, and just lower the gearbox tail to suit. A few hours work, and you don,t have to take the engine out. Just collect from Suffolk.
If you want to do it easily with a minimum of fuss I,ve got a pair of Roy Smarts bolt-on engine lowering mounts for free. Uses existing bolt holes, and just lower the gearbox tail to suit. A few hours work, and you don,t have to take the engine out. Just collect from Suffolk.

Whoops !!!!!

That will teach me not to read the posts properly. I see you have already done that.

Nice thought Graham, cheers. Lowering the engine isn't the problem, it's getting the gearbox lower by a similar amount, (so that the engine remains level), is the real pain! Clearly the chassis brace under the bell housing needs to be modified and I'm hoping for some clues as to how to go about it.....I'm not confident enough to start carving up my chassis!


Brian Magee


This is what I did on Chris Coles's chassis to lower his gearbox. His gearbox was inverted so it may not work on yours but it might give you an idea.



  • Chris Cole chassis mod.jpg
    Chris Cole chassis mod.jpg
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Hi Brian, thanks for that, it might give me a bit more clearance under the bell housing - I'll check the car and see.

Hi Frank, pretty sure it's a Renault 30 bell housing mated to the 21 turbo box - as I said if I can manage to eke out 25-30mm I'd be happy:)
Hi Frank, was wondering why you asked about the bell it possible to modify it to gain some chassis clearance?