Does a 302 engine need lead replacement and octane booster

J

John S

When I bought the GTD40 from Ron there was still some Castrol Valvemaster Plus in the door pocket. This is a lead replacement and octane booster. Do I really need that for an 'older' 302 engine when buying 95 petrol? My engine does not have a light weight alu head, I believe.

This 250 ml bottle of Castrol seems to be enough for 250 litres of petrol, which seems not too bad. I looked locally and the ones I could find would only treat up to 50 litres. So one bottle for half a tank?

John
 
M

Mark R

Your Octane needs will depend on your compression ratio and timing. Higher octane cant really hurt, but most stock-to-mild 302 motors will run just fine on 95. Do you know what your compression ratio is? Experiencing any signs of detonation or 'pining'?

The lead additive has been debated a bunch over on the vintage mustang forums. Most seem to say use the lead additive unless you have installed hardened exhaust valve seats. I am running a '68 302 motor and try to add some lead additive here and there. Probably every 2or3 tanks of fuel.
 
MikeP

Mike Pass

Supporter
It will depend on the heads you have and what the valve seats are made of and what the compression ratio is. Ron will know what you have fitted. I have the Edelbrock Performer RPM heads and I just use whatever petrol there is - no high octane expensive stuff needed. 302 engines are pretty basic and do not have high bhp per litre outputs and are just a stock engine which uses a large capacity to do it's thing. I would guess that comp ratios over 10:1 you might need to look at better stuff.
Cheers
Mike
 
J

John S

Thanks Mike, that sounds reassuring. I will try to find out more about the (state of) engine, looking for a local engine specialist now.

John
 
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