Hi All, had my 3500cc V8 in a workshop for a year, bloke tackled body work, electrical stuff etc. Also did the Carbs SU. Since then it feels as if it's operating on 4 cylinders. Very weak. Any ideas would be helpful. Ta

Check the mixture adjustment, there is a small pin under the float chamber, it pushes the piston up slightly. If the mixture is correct the engine revs should increase slightly, then return to normal. If the revs stay increased it is too rich, if it slows it is too weak.
Are both carbs opening at the same time and are they opening fully?
What's the cam like? They do have a habit of wearing lobes, if this happens they tend to spit back through the carbs at high revs.

Pete Kemp said:

Hi All, had my 3500cc V8 in a workshop for a year, bloke tackled body work, electrical stuff etc. Also did the Carbs SU. Since then it feels as if it's operating on 4 cylinders. Very weak. Any ideas would be helpful. Ta

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In addition to @Rougharse Racing above, it would really be worth starting with your ignition system first...especially where your garagiste has had the vehicle for 12mths and one never really knows the knowledge of a non-RV8 workshop. Run through the following to get back up and running.

1. Correctly set the timing both static and dynamic, and make sure all ignition components are in tiptop condition.
2. Fit new RV8 fuel filter [ideally with a correctly set fuel regulator] + [poor fuel flow/volume and you'll never see full power].
3. Check the flow volume + flow into the SU's [poor fuel flow/volume and you'll never see full power].

With the basics complete, now to move onto the SU carbs...

4. You need to ensure both carbs have both equal air and fuel volume at precisely the same time to ensure both banks are being fuelled identically. I really recommend you buy this book if completing yourself

How to Build and Power Tune SU Carburettors (Speedpro)​

to ensure both carbs are in perfect condition with no mechanical failures/issues, all components correctly set up [needles, jets, springs, pistons, correct pot oil, float not leaking/flooding, no gasket leaks +++
5. with engine warm, set up idle air:fuel mixture with linkages lose and choke off.
6. switch off engine and tighten linkages, re-start engine and re-check idle air:fuel mixture.
7. take for test drive - if any issue of poor running it's 99% this is a fuelling problem rather than ignition/timing [but the ignition/timing at off idle/normal driving can still cause your symptoms...especially if coil or condensor breaking down under load and/or distributor springs weights not functioning correctly and/or rotor arm breaking down +++.
7. then check off idle at ~2500rpm - the air:fuel mixture should again be identical - if not, re-start tuning the SU's at idle until all is well.

Come back to us once you've completed the above.

eta you'll need a good carb balancer to obtain correct air flow and balance - this one works very well.