# Pontiac Engine Education



## Pontiacpurebrred (Jun 22, 2011)

Well I am wondering where one could educate themselves about the manufacture and specifications of Pontiac engines. As I have stated I am quite familiar with the 400 line (I have owned 3 different engines from both the 60's and 70's - early and late) but now I find myself in uncharted waters being the new owner of a 1964 389. It's my understanding that everything Pontiac made from the 321 to the 455 was all the same basic block only differentiated by bore and stroke. I'd like to read up on what my options are for this block and see if I want to keep it or move on to a 400, 428 or 455. I know there are a lot of fans of the 400 stroked out to 461, but I am a hands on guy I want to figure out on my own what suits me best. Is there anyplace online (I have LOTS of time on my hands at work during the day) that I can read up about the 389 and the entire Pontiac line? 

Thanks as always.
Scott


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## freethinker (Nov 14, 2009)

Pontiacpurebrred said:


> Well I am wondering where one could educate themselves about the manufacture and specifications of Pontiac engines. As I have stated I am quite familiar with the 400 line (I have owned 3 different engines from both the 60's and 70's - early and late) but now I find myself in uncharted waters being the new owner of a 1964 389. It's my understanding that everything Pontiac made from the 321 to the 455 was all the same basic block only differentiated by bore and stroke. I'd like to read up on what my options are for this block and see if I want to keep it or move on to a 400, 428 or 455. I know there are a lot of fans of the 400 stroked out to 461, but I am a hands on guy I want to figure out on my own what suits me best. Is there anyplace online (I have LOTS of time on my hands at work during the day) that I can read up about the 389 and the entire Pontiac line?
> 
> Thanks as always.
> Scott


the 400 is just a bored out 389. engines over 400 cu in were a different block in that the main bores were bigger.


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## Pontiacpurebrred (Jun 22, 2011)

Ahhh but if memory serves, at several points over the years Pontiac has made subtle changes to the blocks. 50's to 1960 changed and then again in 65 I believe. What I want to do is educate myself about what I have with a 1964 389 - I think it's already been bored .60 over and is technically a 400. BUT.....what can I do with it from here? 

And are you saying that the 421 and 428 blocks are different crank bore as are the 455's?


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## likethat (Oct 5, 2007)

Same crank bore 455 421 428.

Wallace Racing- Pontiac Engine Bore Size's


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## geeteeohguy (Feb 2, 2008)

The '64 389 uses stud-oiled rockers. The early ones, anyway. The '65 up blocks used pushrod oiled rockers. There is nothing wrong with the 389....I've been running one in my '65 GTO for decades, and it makes a ton of power. The "small journal" (3 inch, which is HUGE) blocks like the 326, 350, 389, and 400 are much stronger than the "big journal" blocks, and are therefore favored (the 400, mainly) for stroker build-ups. Good luck with your project.


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## jetstang (Nov 5, 2008)

The 66 and prior 389s had smaller valve heads then all the later 2.11 valve engines. This is because of the valve location in the 66 and prior engines. The 2.11s flowed better. The 6X head is one of the best flowing heads, but was produced on 8-1 compression motors, leaving alot on the table. You can put 400 pistons in your overbored 389 and run any of the later heads, depending on if they bolt to the block. Or if the rocker oiling can be converted.. Good luck.


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