# Questions: Exhaust Manifolds/Headers for 1969 #16 Heads



## Bill68GTO (Feb 18, 2016)

Hi, I am new to the Forums and need some help from the Pontiac experts. I am a novice mechanic at best, but I am trying to learn as I go. I have a 1973 455 block with 1969 #16 Heads. I was surprised to find that the exhaust port on each end of the Head only has 1 bolt hole for the manifolds (and 2 in the center). Is this correct for these Heads? Has anyone put Headers on these type Heads? Do I need to have a machine shop add another bolt hole on each end to properly bolt up Headers? I found stock 1969 manifolds online (with just 1 bolt hole), but they look small and wouldn't that restrict power? (not looking to race, but would like the 455 to breathe a bit). Any suggestions on how I should proceed? I have heard that #16 Heads were good ones to have and use, is that true? Thanks for any help or suggestions you can offer.


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## Pinion head (Jan 3, 2015)

Welcome to the forum. Before addressing exhaust needs, the 16 heads you have may be dated in '69, but will be cast with F or later of '69 dates. These small valve '70 model 16's were for use on certain 70 400 with auto transmission. The tipoff is the non drilled outer bolt holes, and the small valves... similar deal to the '70 model 15's, (which came on the base '70 455 Bonneville engine code YH). Both of these casting number heads will have stock press in studs. I've had quite a few pairs of both off core engines over the years, with the '70 model 15's being fairly strong sellers.

Big valve 16's were used on '68 400 4bbl and 428 4 bbl engines, and contrary to Pete's well copied Pontiac book, they were NOT used on '69 model 400 or 428's. 428 oem pistons originally had 4 valve reliefs with a small dish, so CR using the same year 400 4bbl head would be tolerable on base premium fuel. You could spend quite a bit of funds modifying the small valve 16's, valve seat and port work, adding new 2.11/1.77 valves, screw in studs, drilling and tapping for the extra exhaust holes, OR you could simply pick up a set of 6x-4 heads and have them milled slightly. The 6x or 5C heads will actually have better stock flow characteristics. 

What cyl head you need will depend a lot on pump gas availabilty and on the rebuild of the 428 and what pistons you choose. A good part of the country does not have 93 octane pump gas, and with 91 octane being the highest octane pump fuel avail, it pays to plan accordingly in a cast iron head performance build.

Have you had the 428 block ck with a dial bore gauge? Had the crank miked? By doing so, will know what you have, if the 428 is just acore. There are a lot of different ways to go with a 428 core. I've had 428s built for restoration use, as well as having '69 428 YH code blocks built with 455 cranks. One of my favorite previous builds uses an offset ground 4" crank, a 455 block, and ported milled 7k3 heads for a very strong pump gas friendly 451.


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## Rukee (Feb 8, 2007)

Welcome to the forums!! :cheers


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