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-   -   Piston size ID 389 (https://forums.maxperformanceinc.com/forums/showthread.php?t=672740)

badlefthand 08-02-2011 06:47 AM
Piston size ID 389
 
Have a 59 SR 389 that I tore down ,Low comp. Dished piston GM#532289. I think std bore but have no way to measure. My Thanks, Machine shops are far away here. Last time I went through this one guy brought out a 12 foot tape,said "yup 4 inches."so drove to a couple machine shops 40 miles away and got a differant measurement from each WTF. Have checked web and nothing.Live on a pretty close budget to buy tools to check size.

gmil60 09-22-2011 08:08 AM
Dear Member,
The Bore diameter for your SR 389 is 4.063 Compression with the dish pistons 8.6

Regards Gerry

pfilean 09-22-2011 07:53 PM
If the pistons are oversise I would expect some stamping on the top surface like 030 060 etc.

Stuart 09-22-2011 08:36 PM
Quote:
Originally Posted by pfilean (Post 4422899)
If the pistons are oversize I would expect some stamping on the top surface like 030 060 etc.
^ this. Every oversize piston I've ever seen was stamped.


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