Good evening all,

I currently have a 1986 LR90 which has a 300tdi engine with LT77 gearbox (all done prior to my purchase).

I am looking to have the chassis and bulkhead changed and want to try and make it as legit as possible. Someone has said to be today that the best bet would be to get a 300tdi chassis (so the engine mounts are all correct) and then change the gearbox for an R380 so that it all lines up as it should.

Having thought about this what other changes would need doing e.g. would I need a new tunnel, new props, etc?

or….. is there a way of getting the LT77 fitting to the 300tdi whilst using the original mounts on a 300tdi galv chassis.

My mind is currently blown and I have lots of people telling me different things. Thank you!

If you were to use a standard 300tdi chassis with a long bellhousing R380 gearbox, you will need 300tdi props, 300tdi gearbox crossmember, the transmission tunnel is different and the front of the seat box needs modifying. This is because the transfer box is mounted 2 inches further forward.
There is a good argument for putting the 300tdi in its standard position, but you can get galvanised chassis with 300tdi/LT77 mounts fitted.

Rougharse Racing said:

If you were to use a standard 300tdi chassis with a long bellhousing R380 gearbox, you will need 300tdi props, 300tdi gearbox crossmember, the transmission tunnel is different and the front of the seat box needs modifying. This is because the transfer box is mounted 2 inches further forward.
There is a good argument for putting the 300tdi in its standard position, but you can get galvanised chassis with 300tdi/LT77 mounts fitted.

Click to expand...

Rougharse Racing said:

If you were to use a standard 300tdi chassis with a long bellhousing R380 gearbox, you will need 300tdi props, 300tdi gearbox crossmember, the transmission tunnel is different and the front of the seat box needs modifying. This is because the transfer box is mounted 2 inches further forward.
There is a good argument for putting the 300tdi in its standard position, but you can get galvanised chassis with 300tdi/LT77 mounts fitted.

Click to expand...

Rougharse racing thanks for the speedy reply. Oh really who would I approach for one of these chassis? Would that mean the engine would be in the correct position aswell even though it had the LT77? Also the bellhousing and the engine don’t currently have the same stud pattern where they meet so there are numerous fixings missing, is there any way around this? I only noticed when looking today and I don’t like the look of it

discodom1 said:

Rougharse racing thanks for the speedy reply. Oh really who would I approach for one of these chassis? Would that mean the engine would be in the correct position aswell even though it had the LT77? Also the bellhousing and the engine don’t currently have the same stud pattern where they meet so there are numerous fixings missing, is there any way around this? I only noticed when looking today and I don’t like the look of it

Click to expand...

The 300tdi wasnt mated in any landy to a LT77 so you need to drill & tap the studs that dont line up.
Steve parkers do a 300tdi engine bracket conversion that bolts on.
SPCK300EBK 300TDI ENGINE CONVERSION BOLT ON BRACKET KIT DEFENDER LT77GEARBOX (steveparkers.com)

Chassis from Richards.........
Defender 90" :: Products :: Richards Chassis
Chassis from Mashland
KD-LR | MARSLAND CHASSIS
Shielder
Replacement Land Rover Chassis | Shielder Chassis UK

Do your research before deciding who to buy from. Top down is the order who I would buy from.

It is normal for there to be missing studs in the bell-housing when the 300tdi is mated to the LT77, the only additional stud that you can / should add is the one in the 6 o'clock position. The stud pattern is the same on the LT77 and R380, the only issue is that the slave cylinder is on different sides on the LT77 and R380 so you end up with missing studs. This website covers 300tdi to LT77 conversions and may reassure you.https://www.glencoyne.co.uk/tdi300.htm My 110 has a 300tdi mated to a LT77 and I haven't had any issues.
There are a number of chassis suppliers, Marsland are the original equipment suppliers I believe and you can identify their chassis from the central welded join on the top and bottom faces of the main rails. Other chassis manufacturers have welded joints on all four corners and I suspect that they are more likely to do custom engine mounts. Do your research though as some of the manufacturers have a shocking reputation.
If you use a standard 300tdi chassis with the engine mounts in the standard position, you cannot use your existing LT77 as the bell-housing and input shaft are too short.
Before you decide on the chassis variant, you need to establish which engine mounts you have on your vehicle at the moment, There are two types, those that use 300tdi rubber mounts and weld to the chassis, or custom mounts that bolt to the engine and use the original 2.5N/A or 200tdi chassis mounts.