My 68 currently has a 400 taken from a 70 GTO. I was wondering how I can identify specifically which cylinder heads I have. They are #16 heads with an August of 69 casting date. From what I have found online they could be anything from a small valve head to Ram Air III heads. What is the best way I can identify what they are without pulling the heads and measuring valves? Any info would be greatly appreciated.
My memory does not work like it used to so I have forgotten many of the finer details about castings. That said there are many resources both in book form and online with everything you would ever want to know, the only thing is to make sure and cross reference because sometimes there are mistakes. Here's one source http://www.wallaceracing.com/head1.htm and scroll down near the bottom part of the page. Being an august date they are most likely a 70 head which Wallace shows' as all having the same size valves. One of the easiest ways to see if a Pontiac head is a stouter performance version is to pull the valve cover and see if it has the heavier duty screw in rocker studs and pushrod guide plates verses press in rocker studs. Unfortunately one of the more pervasive lies some people tell when selling a first gen bird with a non original 400 is to say it came out of a ''GTO'' because it makes it sound better than to say it came out of a 4 door Bonneville. The reality is in most cases if the motor is completely stock the only major difference is the heads cam and timing curve all most likely changed anyways.
So according to Wallace Racing in 70 there were two #16 heads, so is the difference there in the HP numbers which ones would be press in studs vs screw in studs? My other source I have looked at is http://ronspontiacpage.com/reference-pages/stockheadspecs.htm According to this he says that the year may reflect the casting date. It also includes many more years with #16 heads including RAIII which Wallace Racing doesn't list. I supposed the only way to really know is to look at the studs and measure valves. I have been assuming its some of the weaker heads but I had a little hope they may be better.
I had a couple of strokes this past spring and have forgotten a lot of the finer details. From what I remember RA III was 69 and 70 only and none were casting # 16, but hey I could be wrong. As far as what year to look at with your cast date you have to remember production of a model year stops and they retool the plant for the next model year somewhere around August. As an example my current 68 convertible was produced in the 5th week of Sept. 67. With your Aug. of 69 casting date on your heads they would be for the following year and from what I remember there were no Hi/Po 16s in 70. But as you said the easiest way is to look for the screw in studs and pushrod plates and if you know what your looking at you don't even have to pull the cover because you can get a small peek through the oil fill cap with a light and a good set of eyes. Also there is no need to pull heads to look at the valves I'm pretty sure in that year if you have press in studs you have the smaller valve heads. One other note when you are looking at Pontiac heads that have been removed from an engine If you have seen enough of them you can spot 2.11 1.77 big valve heads with a glance. If you don't have experience the easiest way for a novice to tell what you have is to remember that the big valve heads have almost no space between the valve heads they almost look like they are touching. I have seen people at swap meets advertising their heads as big valve Hi/Po when they are not and with just a glance you will be able to spot the B.S. Let us know what you find. I should clarify you can have push rod guide plates with press in studs.
the 69 date code is sufficient to identify your heads as small valve. Press in studs could be seen through the fill cap hole probably, and be decisive.
