[Land-speed] Still Asking Motor Questions, lol..

[Larry Mayfield]

Well, thanks to the folk who answered my basic question. As a result of 
the answer that Dave gave and Rick seconded strongly, I went searching 
some more.  I have located a 4340 forged 289 crank AND 5.155 H beam 
forged 4340 rods. The compression height for the 289 is the same for the 
302 with teh OEM rod and stroke lengths. When I think about it, that has 
to be since the deck height is the same.  Forged 302 dished pistons are 
readily available so no issue at all there.

Rotating assy solved!

Now to just get the stuff....

Thanks again!

mayf

On 3/12/2011 10:19 AM, Larry Mayfield wrote:
> Not being known for motor building prowess, I rely on the list to help 
> me along.  Of late, I have been thinking about the use of a 289 Ford 
> (what else?) crank in the Mexican cast block I will pick up in June. I 
> would like to use the 302 Ford 5.090 rods rather than the hard to find 
> 5.155 rod length of the old 289 series motors. And I want to consider 
> the use the 302 version of pistons for the same reason as availability 
> in race configurations. That puts the piston down hole by 0.065 
> inches, however.  That would reduce the compression ratio quite a 
> bit.  But, I normally use dished pistons with about a 13 cc dish 
> anyway.  So if I use flat top pistors, I think I can maintain the 
> basic compression ratio, but, the "squish" would go away. At least I 
> think it would. I do run the turbo on the motor but What I would like 
> to hear comments on doing this.  Is this something stupid or actually 
> reasonable to do on a boosted motor?  Is it likely to run well or just 
> so so?
>
> No, I don't want to deck the block or mill the heads or find pistons 
> with a longer wrist pin compression height. I know I can do those 
> things, so, the question is can I do it the way described above and 
> have a good performer?
>
> So, you gotta ask..why? Well, I keep looking at the rule book about 
> displacement verification using the pump.  If the as pumped 
> displacement is within 3% of top or bottom of the engine displacement 
> class size then according to the book, it must be torn down for direct 
> measurement.  That's really the last thing I want to do. So if I can 
> keep the motor size for a D motor to 289 - 296 cid range I should 
> always pass a pump check and never have a tear down on the salt.  Not 
> that I am worried about it because I don't think me or the Sunbeam has 
> the beans or aero to qualify or set a record but..just in case, lol. 
> And maybe someone else will benefit from this question in some other 
> situation.
>
> mayf
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