Triumph Sports Cars

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

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Tac-D
Jim Meeks
Tampa, FL
(4 posts)

Registered:
04/25/2019 02:43PM

Main British Car:
1975 Triumph TR6 Ford 302

Mandatory upgrades?
Posted by: Tac-D
Date: April 25, 2019 05:13PM

Hey guys.

Iíve recently inherited my fatherís 1975 TR6. Itís been converted to a Ford 302, with a C4 automatic transmission.
Beyond that, to my knowledge, the rest remains stock. He didnít drive it much, and when he did, it was decades ago.
The interior is shot, seats are ok, but not original, so all that will need replacing.
The engine and transmission have been recently rebuilt, and run great. Iím told the engine produces around 300hp.
Iíve spent a lot of time on here (too much) trying to figure out what the mandatory upgrades are for adding this much power and torque.
Are there any resources that spell out precisely what is needed, at a minimum, for modifying the TR6?
I was prepared to pickup a new frame from Rat-Co or Fast Cars, and build up from there, but the frame seems just fine. No rust, strange welds or holes at all.
Iíve read enough to know the wiring is mandatory, and a differential is highly recommended. Anything else?
This will be a fun driver that will never see a track, but local car shows are possible.
Sway bars? Rear suspension? Bigger brakes?
I will be adding an EFI for sure, is there a preferred brand/model?

Thanks for taking the time to read this. This site is amazing, and has my head swimming with ideas. Canít wait to hear yours.


88v8
Ivor Duarte
Gloucestershire UK
(629 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: Mandatory upgrades?
Posted by: 88v8
Date: April 26, 2019 07:06AM

Hello and welcome.

Unless you prefer tinkering to driving, I wouldn't rush to upgrade things. Drive it for a while as it is. Too easily cars turn into a 'project' and then life gets in the way and they sit and sit and never see the road again.

Injection is not mandatory. Nothing wrong with a 4bbl. It may need a clean and gasket refresh.

The differential, one problem you have is that the C4 is not an overdrive box so the overall gearing is low. About 20mph/1000 depending on the tyres.
Oh, and if the tyres are more than ten years old, replace them regardless of tread.

The easiest upgrade of the diff is a Nissan R200 viscous lsd with Richard Good's kit
[goodparts.com]
His parts are good quality and will save you a lot of bother.
The differential mounts on the frame should be reinforced, they are prone to cracking. I can't point you to a kit in the US, perhaps someone else can. Needs a competent welder.

As to diff ratios, you want the 3.54, but that will still only give the 20 mph that I mentioned, .
So, the one upgrade I would go for if you want to do any highway driving, is an overdrive. They are available as an add-on.
[www.mustangandfords.com]

Sway bar... it already has. They corner pretty flat anyway.
Some people like tubular rear dampers, I found the levers OK.
The brakes are fine, there are alloy calipers available and vented discs if you want.
The best brake upgrade is to improve the handbrake with extension levers, I may be able to find them on eBay.

Seats, Miata seats, the low-backs, are comfortable and look 'period', adaptor brackets are available. But if you're over 6ft you will do better to stay with the standard seats as they have slightly more legroom than the Miatas.

Mainly though, do the minimum and enjoy it for a while.

Ivor


tvrgeek
Scott Stubblefield
Hillsborough, NC
(13 posts)

Registered:
01/25/2019 11:53AM

Main British Car:
73 Stag TR 3.0

Re: Mandatory upgrades?
Posted by: tvrgeek
Date: April 26, 2019 09:38AM

In my experience, bang for buck is IGNITION. The stock ford TFI is a superb system, but you are still left with mechanical curve. A Davis DUI, which runs the GM HEI module. Davis will curve to your engine specs. Being a Ford, I bet most speed shops or dyno operators could recurve whatever dizzy you have. You want to be able to run a stock .7 Ohm coil. TFI/HEI type coil.

I ran a Jag 2.88:1 in my 2500M with a 5.0 and C4. It seemed about right. ++ though on the Nissian rear. The stock TR-6 pumpkin can eject teeth with a stock engine.

GOOD half shafts are a good idea to prevent the intermittent binding of the stock ones. I used a fancy HP grease in the TVR and did not have a problem, but it is common. Nothing like it binding when you let off in a corner. Instant tail wag. Not cheap, but smart. I believe it also upgrades the hubs as you can't get Corvair hubs any more.

Has the cooling system been upgraded? Stock was insufficient for the 100HP 6 banger. I ran a huge BeeCool in my M.

There are several TBU units out there. FAST, Holley, Edlebrock etc. All work. You won't get more power, but can get better drive-ability. I ran fine with a Edlebrock carb. I have been told the FAST is the most advanced. You could swap the manifold and go sequential port injection. closed loop with a stock FORD ECU.

Of course, more tire! Might consider a set of Porterfield pads on Brembo rotors.


88v8
Ivor Duarte
Gloucestershire UK
(629 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: Mandatory upgrades?
Posted by: 88v8
Date: April 27, 2019 04:53AM

'More tire'....... well perhaps.
My TR6 had Shelby wheels,. 7", with 215/70s.
At the front they tramlined.
At the rear they stuck out beyond the arches and in wet weather they splashed the bodywork
And they looked a bit cartoonish. And made the steering heavy.
Was going to change the wheels to 6" and go for 165s on the front and 185s on the rear, then I sold the car so it never happened.
More, sometimes better, or not.

Ivor

Tyre smaller.jpg


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