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

[Larry Mayfield]

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