Triumph Sports Cars

engine swaps and other performance upgrades, plus "factory" V8s (Stag and TR8)

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Ivor Duarte
Gloucestershire UK
(819 posts)

02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

350/350 combo - undergeared?
Posted by: 88v8
Date: August 22, 2015 04:16PM

This TR6 ticks many boxes for me, chiefly that it's all done and it's a right-hooker. Not quite true that there are no other TR6 V8s in the UK, but there certainly aren't many. Unmodded bodywork other than a raised rear edge on the bonnet, nicely trimmed.
It has much to commend it.

However.... it's pretty clear from the Info Sheet created by the previous owner that it was built on the cheap. It has a standard TR6 rear end, and a TH350 or 400 box, seller couldn't say which. He seemed not to know that a B&M Quicksilver isn't a gearbox....
And he was rather evasive abut the overall gearing, but I reckon it's got to be about 21mph/1,000rpm.
This seems awfully low.

Now, I know I can put in an R200 rear end with a Goodparts kit. I want an autobox and I could convert it to a 700R4, but that will cost, and the price isn't exactly keen.

A crate 350 sitting at an 80mph cruise of 3,800rpm is going to eat fuel. How happy would it be at those cruising revs?


Jim Purdy
Memphis, TN
(129 posts)

12/06/2013 03:54PM

Main British Car:
61 austin healey sprite LS6

Re: 350/350 combo - undergeared?
Posted by: Anarchy99
Date: August 22, 2015 08:50PM

A th400 and a 2004r are roughly the same dimensions and you only have to modify most trans mounts a little bit to make them fit. It'll get you overdrive and if you already have a th400 it's a fairly straight forward swap, just a TV cable.

Doug Rowe

(50 posts)

07/04/2012 05:09PM

Main British Car:

Re: 350/350 combo - undergeared?
Posted by: Sidecardoug
Date: August 22, 2015 10:21PM

Basically the same issue as with my TR6/Ford/C4. Rear gears are a no-go. The TR6 comes with 3.69:1, the best the GoodParts can do is 3.54:1, IF you get a diff sourced from the Z car. The 700R4 or 2004R is probably your best bet. If the exhaust runs alogside the driveshaft, a GearVendors overdrive almost certainly won't fit. Without the exhaust in the way, you might be able to fit one with a bit of sugery to the tunnel cover. The GearVendors overdrive is about $3000 US with the tailshaft adaptor.

One thing to watch for with the 700R4, is that they don't like to be run in overdrive below 45-50mph, as the pump doesn't spin fast enough to maintain best pressure. There are kits available to fix this, probably found
through Summit Racing or Jeg's.


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