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#1
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59 Engine Question
I'm familiar with Pontiac V-8's...from 67-78....but just learning about early 389's
According to Pete's book...ALL 59's used the same head casting.....so how did we achieve 3 different compression ratio's of 7.8,...8.6 and 10.00? I see that different cams were used...but don't think they would change that much in CR... Were there reliefs ground in cylinders. to reduce CR..like the 409 truck motors? I need to check my block cast number......Hopefully that will tell me what I have.. Last edited by Green Hornet; 04-07-2020 at 01:22 AM. |
#2
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Lower compression ratios were achieved with dished pistons, export engines had reduced compression as well. No difference in block machining.
The 10.5:1 Tri-Power engines had the heads milled .030” if I’m not mistaken. Dished pistons: https://www.ebay.com/p/1070477518?ii...BoCcxYQAvD_BwE The vast majority of 1959 389 engines were the A-code 280 hp 2-barrel version which is likely the one you have. Link to thread with more ‘59 389 pictures and information: https://forums.maxperformanceinc.com...d.php?t=781327
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#3
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He has a Bonneville. Same exact engine as the 280hp with a 4bbl carb making it 300hp. Same compression, same valve train, just more air into it. I was under the impression that the combustion chambers for the 10.5 engines was cut a little shallower, but I could be wrong. Pontiac did machine their combustion chambers......John
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