Thread: New 350sbc do i have a blow head gasket? Or something worse..

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Welcome to CHR!

Wow – there’s so many things in this post I could address, but I’ll try and focus on just a couple that may help you out. A stock 350 should run fine on regular gas – a tank of premium just before a long freeway trip may help clean things up a bit inside the combustion chambers but otherwise it’s a waste of your hard earned dollars.

You need to ditch the electric fans and find the proper shroud for the radiator and put the stock GM fan and clutch on your engine. It is the most efficient and best engineered combination of parts for all but the most radically built engines. The only time I use or recommend electric fans is for very specific clearance issues and then they still must be used with a shroud (see below). All electric fans that I use are on separate relays and draw between 20 and 30 amps. Trust me – the stock GM unit is the best combination for your car.

More important right now is the oil in the water – don’t know who told you, “You were lucky…” because in all likelihood that was the first sign that you’ve got a “not-so-little” issue. The oil and water systems are both closed loops and are designed to NEVER meet each other. At a minimum, you have a bad head gasket – worst case could be block damage, depending on how hot things really got. I’d recommend pulling the heads and seeing if that’s where the oil and water mixed – if not, obvious, there’s a crack internally that is allowing the two fluids to meet – not a good thing. Either way the engine may need to come out. Don’t be upset with the mechanic as this is in all probability attributable to the electric fans.

Sorry to rain on your parade. If you truly want to learn about your engine, I’d suggest buying “How to Rebuild Your Small-Block Chevy” by David Vizard and reading it cover to cover. It’s a $20 softbound book that you can buy from Amazon and it gets into the basics as well as advanced aspects of small block Chevy engines.

Good Luck,
Glenn