Return-Path: Received: from [161.91.247.12] (account ) by logan.com (CommuniGate Pro WebUser 4.1b2) with HTTP id 2093370 for ; Mon, 31 Mar 2003 09:34:30 -0500 From: "Marvin Kaye" Subject: Re: [LML] Legacy Tuned Exhaust To: lml X-Mailer: CommuniGate Pro WebUser Interface v.4.1b2 Date: Mon, 31 Mar 2003 09:34:30 -0500 Message-ID: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format="flowed" Content-Transfer-Encoding: 8bit Posted for "Gary Casey" : If I'm not mistaken the engine shown in the picture was an IO-520. I have a Continental drawing that shows the exhaust port being 2.36 inches fore-and-aft and 2.00 down from the centerline of the cylinder and 12.77 out from the centerline of the crank. The spacing between bores is 7.31 and the stagger between banks is 2.46. My IO-550 drawing is incomplete, but shows the port the same 2.36 inches from the cylinder centerline, but 2.56 inches down. Further, the IO-550 exhaust port is 1.69 diameter with a 4-bolt flange while the IO-520 has a 1.547 diameter GASKET and a 2-bolt flange. I believe, but don't have proof, that the bore spacing and stagger of the 520 and 550 are the same. They seem to be, like I say at work, exactly the same except different. Gary Casey