# Engine questions



## SIXT5GTO (Mar 9, 2010)

The other day I was speaking with someone about 389s. and was asked about mixing parts of post and pre 65 engines
I understand the heads and intake can not be interchanged between pre and post 65.
Is there any reason why post 65 heads cant go on a pre 65 blocks.or the other way around
There has not been anything I have read that gives me the impression newer heads cant go on older block( i understand there was changes in the valve oiling systems) I know of but did not want to give an answer on it because I just dont know for sure. I have only been messing with a 65.:confused


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## Willshire (Jul 14, 2011)

i have a 64 and it is my understanding that you can put 65 and newer top ends on earlier blocks but this requires heads valley pan, intake etc. i don't think you would want to go the other way as early heads were not as good as 65 and later. that is not to say you couldn't produce 350 hp from a pre 65 engine. my experience is limited but i am pretty sure the top ends are interchangable.


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## geeteeohguy (Feb 2, 2008)

The top ends are indeed interchangeable. Pre-'65 intakes are longer at the rear runners and have a water outlet at the front instead of the nipple at the back of the passenger side head. '64 and earlier ('66 really) head tech wasn't nearly as good as '67 and up, and these closed chamber designs are prone to detonation and need a lot of timing to make good power. Fine for 100 octane. '64 and earlier heads also oil the rockers thru hollow studs instead of the pushrods. Earlier 389s have no provision on the block to mount the starter....it mounts to the bellhousing. I'd stick with '65 and later if it's a '65 model year.


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## Rukee (Feb 8, 2007)

:agree valve train oiling was much improved with the `65 and later GTO head design. I would would run with that if your able.


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## SIXT5GTO (Mar 9, 2010)

Thanks for the education, I just was not sure,
Our car has the 65 YS block and 77 heads, and the timing having to be set just right is so true


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