LT1-LT4 Modifications 1993-97 Gen II Small Block V8

383 Question....

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Old Feb 26, 2007 | 12:07 AM
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Default 383 Question....

Well, I will ask this here since this section moves faster than the other for older sbc engines.....

I am in the process of builing my sencond engine for my 1975 camaro, I do not want to build a regular 350, I am looking more to build a stroker engine. I have an engine that came out of a 1990 chevy truck, its a 2 bolt main, one piece rear main seal. What modifications will I have to do in order to stroke it, I will buy a new crankshaft designed with the 350 block mains, but 400 block stroke. Will it have any clearance issues? will it have to be machined to allow the bigger stroke? Thanks in advance for any inputs.
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Old Feb 26, 2007 | 12:22 AM
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By the way... I also own the Trans Am you see in the signature picture.......
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Old Feb 26, 2007 | 11:41 AM
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im pretty sure the block has to be clearanced for the longer stroke.
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Old Feb 26, 2007 | 11:54 AM
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Yes the block will have to be clearanced near the pan rail and/or the bottom of the cylinder bore to clear the crank (actually the rod bolts).. The increased stroke brings the rod bolts to where they will hit the pan rail.... Happens on every 350 i've ever seen. what you want is a 350 block bored .030 over (4.030 bore) and run a 3.75" stroke crank..... if you're going all out i'd convert it to 4 bolt splayed mains as well.....

here's what the clearancing looks like underneath the block... just an example (don't give this to your engine guy and go "make it look like this"

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Old Feb 26, 2007 | 08:25 PM
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Thanks for the input guys, it really helps me by looking at that picture, it does give me an idea. I also have a set of fuelie heads that will bolt on that engine, they should do while I save to get better heads, these fuelie heads have had some work done, and have recieved a basic porting and some milling, they were 64cc heads.
Now, I will use the stock rods, which are 5.7", whats involved in using the longer rod 6" and is it a great difference? I would need special pistons for any of these rods, right?
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Old Feb 26, 2007 | 10:27 PM
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Good luck.
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Old Feb 27, 2007 | 02:28 AM
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if you are going to order pistons then you have to order the pistons for the correct rod length.... the .3 difference between the 5.7 piston and the 6.0" rod piston is that the wristpin is moved up .3" higher up in the piston allowing you to use the longer rod...

A 5.85 is the standard rod I believe used in most 383 applications..... you can use a 6.0" rod in a 383 but the wristpin is moved up pretty high into the ring land.... and most don't like to do that especially if a power adder is to be used....
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Old Feb 27, 2007 | 09:33 AM
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Yes, the block will have to be clearanced for the added stroke.

Summit sells 383 kits cheap!
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Old Feb 27, 2007 | 07:52 PM
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I did look into summit, seems like they only list a 383 kit for an engine thats a two piece rear main seal.
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