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factorystock · 01-01-2009, 02:34 PM

The 250 started as a simple engine, and was until '74. In '75 they were built with an integral head and manifold. In '79, more smog equipment was added as shown in above photo. In '79 GM tried to make the engine as efficient as possible for better mileage and power, but became more complicated in the process. The easiest swap would be a pre '75 version, but a '79 250 should work also.The 250 was a long running reliable engine, but it did have a reputation for cracking manifolds (very expensive) on newer versions and blowing out exhaust manifold gaskets on older versions.

01-01-2009, 02:34 PM	#7
factorystock Registered User Join Date: Feb 2007 Location: west coast Posts: 3,399	Re: Anyone Using 4.1 Straight Six Engine? The 250 started as a simple engine, and was until '74. In '75 they were built with an integral head and manifold. In '79, more smog equipment was added as shown in above photo. In '79 GM tried to make the engine as efficient as possible for better mileage and power, but became more complicated in the process. The easiest swap would be a pre '75 version, but a '79 250 should work also.The 250 was a long running reliable engine, but it did have a reputation for cracking manifolds (very expensive) on newer versions and blowing out exhaust manifold gaskets on older versions.