This is topic Destroking an engine in forum Tech Talk at Northern California Ford Owners  .


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Posted by unfknblvbl89 (Member # 1522) on :
 
This may seem like a weird question but I was reading an article about a car and it was talking about how it had a 351 W destroked to a 349. I was wondering if anyone could give me any insight on how this is done or have a link to a web page that might kind of explain the process.

Thanks

Edit: This is just for knowledge purposes!!
Also does anyone know the formula's to figure for cubic inches and compression ratio.

[ October 17, 2002, 12:21 PM: Message edited by: unfknblvbl89 ]
 
Posted by yipnip5.0 (Member # 175) on :
 
opposite of stroking... crank has less stroke..could be a custom crank, or a 351crank offset ground. A good example of detstroking would be put a 289 (2.87-2.89 stroke) crank and rods in place of a 302 (3.00 stroke)... now you have a 289.

Generally this is done to reduce the rod ratio, give a more stable rotating assembly capable of higher rpms and less dwell at tdc.
 
Posted by unfknblvbl89 (Member # 1522) on :
 
quote:
Originally posted by yipnip5.0:
opposite of stroking... crank has less stroke..could be a custom crank, or a 351crank offset ground. A good example of detstroking would be put a 289 (2.87-2.89 stroke) crank and rods in place of a 302 (3.00 stroke)... now you have a 289.

Generally this is done to reduce the rod ratio, give a more stable rotating assembly capable of higher rpms and less dwell at tdc.
Thanks that makes sense, but with your example you used you are talking about using a 302 block(stupid question I know just want to make sure I am clear on this).

There's no machining on the piston heads?
Is there any type of specail machining that has to done to the block. I.E. adding material to make sure the crank fits properly.
 
Posted by yipnip5.0 (Member # 175) on :
 
well destroking offers issues just like stroking does. You risk having pistons way below the deck surface, so you must mill, or use a custom rod to or piston to bring it back up.
No real problem with crank fitting, since that is usually only a problem as stroke increases.

yes, a destroked 302 would be using a 302 block.
Another example is the 429 motor...technically a destroked 460.
 
Posted by unfknblvbl89 (Member # 1522) on :
 
Thanks. I understand what you are saying now.
 
Posted by 5.8L 2be (Member # 786) on :
 
quote:
Originally posted by unfknblvbl89:
This may seem like a weird question but I was reading an article about a car and it was talking about how it had a 351 W destroked to a 349. I was wondering if anyone could give me any insight on how this is done or have a link to a web page that might kind of explain the process.

Thanks

Edit: This is just for knowledge purposes!!
Also does anyone know the formula's to figure for cubic inches and compression ratio.
The 5.0 article about the '97 Saleen with a 349 with twin turbos and over 1000hp? [Big Grin]

http://www.50mustangandsuperfords.com/editorial/article.jsp?id=4268
 
Posted by unfknblvbl89 (Member # 1522) on :
 
quote:
Originally posted by 5.8L 2be:
quote:
Originally posted by unfknblvbl89:
This may seem like a weird question but I was reading an article about a car and it was talking about how it had a 351 W destroked to a 349. I was wondering if anyone could give me any insight on how this is done or have a link to a web page that might kind of explain the process.

Thanks

Edit: This is just for knowledge purposes!!
Also does anyone know the formula's to figure for cubic inches and compression ratio.
The 5.0 article about the '97 Saleen with a 349 with twin turbos and over 1000hp? [Big Grin]

http://www.50mustangandsuperfords.com/editorial/article.jsp?id=4268
Yeah thats where I read it. That is one bad motherf*$ker.
 
Posted by 4.6 EATIN GM'S (Member # 1633) on :
 
so whats the reason for destrocking?
more torque?
i know higher reving but what else? [Confused]
 




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