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355 vs 350

 
ivanogburn
I love my Chevy Chevette!
Posts: 2
Joined: 12/07
Posted: 12/02/07 09:36 PM

Is there any major difference between a new 355 sbc and the standard 350, except the 5 cubic inches? Why is there both a 350 and a 355 cid sbc? Crazy

Also can some one point me in the correct direction to find tune up and pPerformance data/instructions for a 355 sbc? Grin  
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GibTG
I mow my lawn and find Chevys
Posts: 1985
Joined: 10/03
Posted: 12/05/07 05:43 PM

What kind of motors are we talking about here? Gen I, Gen II, Gen III? There have been 5.7 liter engines in ALL of these generations.

When you say "new 355" you confuse me a little. Please elaborate and hopefully then I can answer your question.  
~Gibs

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robjuicer
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Posted: 12/06/07 02:16 AM

Icon Quoteivanogburn:
Is there any major difference between a new 355 sbc and the standard 350, except the 5 cubic inches? Why is there both a 350 and a 355 cid sbc? Crazy

Also can some one point me in the correct direction to find tune up and pPerformance data/instructions for a 355 sbc? Grin


I think you are hearing conversations in which the 355 is mentioned and wondering what the difference is. I am assuming you are new to this and curious. And I will tell you there is NO dumb questions when learning about engines. Many simply skip the jargon and say "355" instead of saying it's an over-bored 350 engine. Some do it to add cubic inches. Others do it because the cylinders need cleaned up to true up the "roundness" of it. Some require only a small amount to be removed to make it true again. If you have an original engine in an older car and want to keep it original, you might want to remove only what's needed, as this car is worth more with THAT engine in it and it may require a rebuild in years to come. Anyway, many in the fold will say 331 (for an over-bored 327), 292 (for an over-bored 283), 377 (for a de-stroked 400), or 383 (for a stroked 350). These people all assume you and everybody else know what they are talking about when they mention these engine sizes. When somebody mentions a 301 chevy engine, for example, I will know it is a "homemade" 302 (4" bore, 3" stroke); one made from boring certain 283 engines .125 over to make it a 4" bore. It's basically the same as the 302's that came in the Z/28's but because "301" was mentioned, I know it's a 283 over-bored. Any time you hear these or other terms used, ASK what they mean. As I said, there are no dumb questions. The sooner you satisfy your curiosity about one thing, it frees up the mind to focus on other questions you have about engines. Time is of the essence, my friend. Learn all you can. I learned all this myself, as many who would throw around these terms didn't actually know. Read all you can. If things don't make sense now, they stay in your mind. There may be a question mark by them but the more you learn and know, the references you've read about will begin to make sense. "How to Hot-Rod a Small-Block Chevy" is a good book to buy. It explains SO much on these engines. As for tune-up specs on these engines, the base-line specs on any 350 is a good place to START. Your cam, distributor curve, jetting, cooling capacity all comes into play. Just hang with guys that hot-rod, build, race, engines and ask questions. Hope I haven't confused you more. Knowing how a 4 cycle engine works; the effect the cam has on an engine, and realizing that an engine is nothing more than an air-pump, you begin to realize what is being accomplished by these techniques used (port volume, port velocity, why and where porting is done, adding cubic inches by either boring or stroking, having the advance coming in sooner, low-tension rings, windage trays, and on and on. These gains, although small in the overall HP picture, adds up. Start experimenting with you engine. Swap smaller chamber heads on your engine and FEEL what happens. That's effectively raising the compression ratio. Couple that with larger valves and you really feel the difference. Get your hands dirty. There's no substitute for experience.  

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s-10stroker
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Posted: 12/06/07 04:22 PM

Simply put,a 355 is a 350 bored .060 over.The best overall place in my opinion for performance parts is Summit.  

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GibTG
I mow my lawn and find Chevys
Posts: 1985
Joined: 10/03
Posted: 12/06/07 05:31 PM

Just to correct "s-10stroker" a 355 in terms of a gen I engine is a 350 (mathematically equals 349.850 cubic inches) bored .030". Which mathematically turns out to be 355.115 cubic inches.

The reason I say "mathematically" is that you would never measure this exact volume if you "tubed" a cylinder. Piston compression height, minute rod length differences, crankshaft stroke tolerance, and small changes in piston-to-bore clearance can affect this, but these variables are insignificant when speaking of an engine's displacement.  
~Gibs

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ivanogburn
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Posted: 12/08/07 03:17 PM

Okay this is the deal.

I just purcahsed a truck that the past owner claims is a new crate sbc 355. Smirk  It has a Street Avenger 270 Holley and edelbrock intake, 194 heads, and pro comp cam. It is pushing a Turbo 400 tranny. This all sits in a 1977 truck.  Laugh  Here is a pic of the engine.
{img=http://img515.imageshack.us/img515/2222/pb180008qe0.jpg] [img=http://img407.imageshack.us/img407/843/pb180009qr3.jpg]
I have seached the web and veriufied that yes you can purchase a crate 355 - not a 350 overbored.  Grin So my question is are the apsrt for a 355 the same as a 350?  Confused  
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gtotomm
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Posted: 12/08/07 11:15 PM

A 350 bored 60 over is a 360. as 40 over is a 357.  

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GibTG
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Posts: 1985
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Posted: 12/09/07 08:58 AM

They are virtually the same, the only difference is that the pistons are a larger diameter in the overbored engine.

The issue with him buying a crate motor is that I don't imagine there are many noteable crate engine builders out there using 30-year old cylinder heads. He either bought a crate short block and used his own induction or bought an assembled engine from a backyard builder and called it a crate.

Exhaust manifolds? Get rid of those! They could be costing you 35-45 or more horsepower depending on how much your breathing potential is being limited by them. It will be a great first step in unlocking some of that engine's potential.  
~Gibs

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350s-dime
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Posts: 3
Joined: 05/08
Posted: 05/18/08 09:00 PM

Get rid of the exhaust maniflod? Is the really robbing me of hp? would it work?
And I was looking to bore my 350 out to give it more horsepower. where could I get this done? or how could I do it my self?  Im new to this help me out.  

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GibTG
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Posts: 1985
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Posted: 05/18/08 09:09 PM

Of course exhaust manifolds cost power! They are mass-produced cast-iron pieces that weren't exactly meant for making a bunch of power, whereas long-tube headers will show significant gains everywhere in the rpm range.  
~Gibs

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350s-dime
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Posted: 05/20/08 08:09 PM

How can I get more hp out of my 350ci?  

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GibTG
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Posted: 05/20/08 08:52 PM

Headers  
~Gibs

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Faceman
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Joined: 01/08
Posted: 05/22/08 12:30 AM

I have a 350 4 bolt block. It was .020 over but the bores were rusty (engine had filled with rainwater through the carb!) Got a set of forged .030 to put in, but it didn't clean up at that. Running out of funds now, do I go .040 or .060 hypereutectics.
350 to 355 to 357 or 360?  

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bryan95
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Joined: 10/09
Posted: 10/22/09 08:28 PM

and a 350 bored 80 over is a 363 like in my drag car. all a 355 is a 350 bored 30 over i built one last spring for my 63 fairlane ya i puttin chevy stuff in a ford the only way it will run  

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gettnlarge01
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Joined: 09/09
Posted: 10/23/09 02:30 AM

Faceman the proper procedure is boring the block first to determine what overbore size will clear the cylinders up. Pistons are measured to establish the size the cylinders will be honed to. Best thing your machinist to do is find the rustiest cylinder and see what bore size removes the rust and then bore the rest of the cylinders the same.  
luck is when skill and opportunity meet

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