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vectorit · 07-24-2010, 01:31 PM

400 SB's are siamesed bore blocks, that's why you need the steam holes in the heads. Problem I have had with these engines, is if it gets a little over normal operating temps the head gasket gives way at those holes. This happens more often when the cooling system is dirty, and the water jackets get sediment in them. Which causes the steam holes to fail at being affective.

When kept in tip top shape they are good motors.

My opinion on them, with first hand experience owning 4x4 Chevy's powered with the 400, 350, and the 327. The 400 to me seemed like a warm running thirsty 350, it wasn't spectacular to the point where I thought they were a must have.

If I was looking for a mil to drop in my truck to pull an RV, I'd go with a BBC before going with a 400 SBC.

JMTC

07-24-2010, 01:31 PM	#6
vectorit What? Join Date: Jun 2007 Location: Southern California Posts: 7,617	Re: thinkin of swapping in a sb 400 400 SB's are siamesed bore blocks, that's why you need the steam holes in the heads. Problem I have had with these engines, is if it gets a little over normal operating temps the head gasket gives way at those holes. This happens more often when the cooling system is dirty, and the water jackets get sediment in them. Which causes the steam holes to fail at being affective. When kept in tip top shape they are good motors. My opinion on them, with first hand experience owning 4x4 Chevy's powered with the 400, 350, and the 327. The 400 to me seemed like a warm running thirsty 350, it wasn't spectacular to the point where I thought they were a must have. If I was looking for a mil to drop in my truck to pull an RV, I'd go with a BBC before going with a 400 SBC. JMTC __________________ Chris 1968 K20 Suburban 1972 K10 LWB PU