which fuel?

What fuel would be best for a holden 308 V8? Premium unleaded, leaded or unleaded?

what year is the engine, what compresion ratio and do you have a cat?

The motor is about a 1979 carbie dont know the compression cat?
just wondering what fuel?

the compression ratio would be the most important question on the list above... the cat question gets you close, though.

if you have a catalytic converter, then you can't run leaded fuel (couldn't ever run leaded fuel, most likely). If the car was built in 1979 and has a catalytic converter, chances are good that it will run just fine on 87 octane. If it never had a cat, then it may need higher octane fuel (and in some cases, "lead substitute").

i aked about the cat because i belive it was the introduction of catalitic converters that make the move from leaded gas to unleaded....(the lead will coat the cat and render it useless)....

so if your car has a cat then use unleaded....if it doesn't see if you can find leaded gas and if not use a lead substitute....

about the compresion if you have more than 10:1 run 91 octane if you have below that you should be able to run 87.....unless you have some very advanced ignition...


sorry to ask all those questions but without this info i cannot give a proper anwer.....

Lets just say that it does have a catalytic converter. Being a V8 is it better to run high octane 98 premium unleaded?

Originally posted by Kashy
Lets just say that it does have a catalytic converter. Being a V8 is it better to run high octane 98 premium unleaded?


if it has a cat then yes it will run with unleaded.....

being a v8 has nothing to do with octane number.....the compresion ratio in the cylinders and the ignition timing will determine what octane you can use without getting detonation.....