67 cam with 396 BB running as high as 230-240
 

I’m a rookie at this as this is my first classic car, question; Will using high octane gas cause my older engine to run hotter than normal? I have aluminum radiator and dual fans but my engine runs hot.

Short answer, no. Double check the gauge is accurate. 230 is pretty hot. Not that it matters, is this at idle or cruise?

This was cruising on highway (55-60) for about 40 mins after picking it up from mechanic. What do you mean “doesn’t matter”? Is that really not that hot?

This comes up fairly often,big blocks make a lot of heat,a radiator with electric fans usually doesn't keep up because they just don't draw enough air.
A standard stock type 6 blade fan with a fan clutch and a full shroud usually takes care of the problem.

Thank you very much, until I look into getting that: at what point should I be concerned and stop running the engine?

I'm no expert but I'd say you are running border line already.
Oh and on the gas,no and in fact you are far better off with high octane in a high compression engine,common misconception is that high octane fuel burns hotter,it does not and in fact is less volatile. Regular gas tends to pre-ignite from compression heat,that's what causes knock and you've probably heard the term dieseling when you turn the key off but the engine keeps trying to run. Diesel engines fire off compression heat (very high compression) without a spark,hence the term.
Higher octane fuels are harder to ignite so they don't fire until the spark pops them off,high performance engines run higher compression which is why higher octane fuels were developed years ago as car makers were striving for more HP by using increased compression ratios.

what is the compression of your engine ???? how many core is the radiator ? how much cfm does the fan move? do you have it pushing or pulling? do you have a shroud ?
these are just a few of the ?s that need answered
I run a sb chevy on the dirt track with 13-1 compression for 3 years that reached 230-240* , but I changed the oil every week

I truly wish I could answer those questions but have no idea. Truly a novice at this. But it feels like its pulling but no shroud. Don’t even know what that is!

Here is a picture showing a stock set up like I suggested with a clutch type fan,the shroud is the big plastic piece attached to the radiator that the fan is inside of.

https://cimg2.ibsrv.net/gimg/camarof...7a91113902.jpg

https://cimg4.ibsrv.net/gimg/camarof...88c400362d.jpg


As you can see here,most of the air has to be drawn through the radiator rather than from around it. The shroud is an important piece.