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Pontiac Big Chief intake question

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Pontiac Big Chief intake question

Postby shoedoos » Wed Mar 30, 2011 12:47 am

I just spotted this pic of an old Spiro Pappas engine on YB, note the Dart intake...can anybody tell me if the standard port configuration of a BB Chev intake is the same as the Pontiac 427 castings? Obviously the water crossover and thermostat housing is gone on this intake pictured....
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Re: Pontiac Big Chief intake question

Postby SMITHBERGRACING » Wed Mar 30, 2011 4:38 am

That is a new one to me? :-k
Those Pontiac 427 heads are a Spread Port and that Intake is conventional. Maybe the heads were modified to bend the rules at the time?
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Re: Pontiac Big Chief intake question

Postby White Lightnin' » Wed Mar 30, 2011 5:12 am

The original "Pontiac" Pro Stock style heads from the late '80s did have a standard big block chevy port location. Most folks in competitive racing immediately began to weld on em and move the port locations around for better line of sight and improved flow. About 1990, the Dart Big Chief's really brought about the "out-of the-box" ready spread port head based off of what Pro Stock engine builders were doing at the time.
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Re: Pontiac Big Chief intake question

Postby BEARCAT » Wed Mar 30, 2011 10:11 am

[quote="shoedoos"]I just spotted this pic of an old Spiro Pappas engine on YB, note the Dart intake...can anybody tell me if the standard port configuration of a BB Chev intake is the same as the Pontiac 427 castings? Obviously the water crossover and thermostat housing is gone on this intake pictured....
[img]http://i363.photobucket.com/albums/oo71/shoedoos/spiro.jpg[/img][/quote]


First off that is the Pontiac valve cover bolted on a Dart or Brodix head not a Pontiac head. The Pontiac 427 is a spread port not a standard port and no Dart intake will bolt to them. The ports are spread more than a inch apart from the front pair to the rear pair of runners. You would have to cut the intake manifold apart and add more than an inch in the middle to spread the intake manifold to line up with the cylinder heads. The Pontiac heads 10045427, 10049875 are spread ports, the Pontiac 10093378, 10093383 were standard port style heads and the Pontiac 10093385, 10093386 are complete spread port heads ( all runners shifted) and all were made by Brodix starting in the early 80's.
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Re: Pontiac Big Chief intake question

Postby shoedoos » Wed Mar 30, 2011 6:15 pm

thanks for the info guys....so which heads does this Edelbrock intake fit then?

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Re: Pontiac Big Chief intake question

Postby White Lightnin' » Wed Mar 30, 2011 8:59 pm

To clarify my previous statement, the Brodix "Pontiac" version of heads I have seen that are straight-out-of-the-box, unmolested heads do have siamesed intake ports, not spreadports. A friend of mine has a set, I'll see if I can post some pic's if I can get over to see them. Those heads in that original photo ARE Pontiac heads, you can tell from the scalloped out areas above the exhaust ports. I also remember seeing Spiro's car run with that engine combination in NMCA Super Street back in 1994-95. Chuck Samuels at Fast Times Motorworks was building his engines then. I believe that intake you have there is for the non-spreadport versions of the Pontiac head. I recall an article several years ago where someone was running a 470-ish engine in Super Street in an orange 1969 Camaro that had one of those intakes on it. The story writer stated it was a "very rare" Edelbrock manifold for Pontiac heads. It too had siamesed intake ports. Not trying to be an a-hole, but I know what I know and I've seen what I've seen. If I can get some pic's of those unported Pontiac heads my buddy has, I'll prove it.
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Re: Pontiac Big Chief intake question

Postby BEARCAT » Thu Mar 31, 2011 12:45 am

The Pontiac did not have the exhaust scalloped out like the heads in the picture. The Pontiac 427 is a spread port head not a symmetrical head. The spread port does not mean that all of the runners are spread, it means that the pairs of rockers are spread apart. If you sit a Dart intake on the Pontiac heads the front pair of runners would line up good but the intake would like about 1 1/2" to reach the rear pair of runners. Slide the intake to the rear and then they would line up. Edelbrock was the only ones to ever make a cast intake to fit the Pontiac pro stock head and only made a few of them. I don't mean to be a a-hole here but I have used many sets of the 427 and 3386 Pontiac heads on engines not just seen some here and there. I you want the true facts call Brodix, they can fill you in on the facts because they were the original manufacturer of the first casted rolled spread port Pontiac heads. Don't mix up the Dart Big Chief and the Brodix Big Duke heads as Pontiac heads, they are 18, 16, 14 and 12 deg heads and are not like the original Pontiac heads. The heads do not have interchangeable parts.
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Re: Pontiac Big Chief intake question

Postby shoedoos » Thu Mar 31, 2011 1:03 am

So reading between the lines here bearcat, the heads in the picture at the top would either be a pair of 378 or 383 castings? And (forgive me if I misread your info), they will fit a standard configuration BBC intake with the obvious water jacket removal?
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Re: Pontiac Big Chief intake question

Postby shoedoos » Thu Mar 31, 2011 2:04 am

PS: here's a pic of the underside of the intake above, just in case it helps ID what heads it will fit?

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Re: Pontiac Big Chief intake question

Postby wizbang » Fri Apr 01, 2011 8:38 pm

Bearcat "The Pontiac did not have the exhaust scalloped out like the heads in the picture. The Pontiac 427 is a spread port head not a symmetrical head. The spread port does not mean that all of the runners are spread, it means that the pairs of rockers are spread apart. If you sit a Dart intake on the Pontiac heads the front pair of runners would line up good but the intake would like about 1 1/2" to reach the rear pair of runners. Slide the intake to the rear and then they would line up. Edelbrock was the only ones to ever make a cast intake to fit the Pontiac pro stock head and only made a few of them. I don't mean to be a a-hole here but I have used many sets of the 427 and 3386 Pontiac heads on engines not just seen some here and there. I you want the true facts call Brodix, they can fill you in on the facts because they were the original manufacturer of the first casted rolled spread port Pontiac heads. Don't mix up the Dart Big Chief and the Brodix Big Duke heads as Pontiac heads, they are 18, 16, 14 and 12 deg heads and are not like the original Pontiac heads. The heads do not have interchangeable parts."

I'm not trying to be an A-Hole here either, but, I think some of the comments are a little misleading.
I have two cast intake manifolds for the GM Pontiac 427 heads, that are not made by Edlebrock. They are both blower manifolds that were sold by Street and Performance. One of them I bought brand new in 1987 for the new set of heads I bouight from GM in 1986. I have four sets of these heads now, two of which on on running engines. The first set are a blown 572 deal, the second is an injected 500 deal.

Two of the sets , not on engines, are the "scalloped" style that are shown in the above pic ? These were the later style castings from what I've seen, that when they scalloped them, they also added the tapped holes for the steam pocket lines.

I think what you see in the above picture is a GM Pontiac head that has a modified Dart intake, possibly to match a pair of modified intake port heads. I've see heads that had the ports moved more towards the "semetrical" style and then the move the ports in the Dart "Big Chief" intake to match. EPD was the one that did this more than other guys.

The one set I have has had the Dart "Big Chief" bolt pattern drilled and tapped in them.

??????????
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Re: Pontiac Big Chief intake question

Postby qtrmiler » Sat Apr 02, 2011 1:00 am

Did you guys see that there is a spacer between the head and the intake not sure if for tall deck spacing or some kind of adapter for a different bolt pattern arrangement.
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Re: Pontiac Big Chief intake question

Postby wizbang » Mon Apr 04, 2011 4:19 pm

I think that is how they made the bolt pattern usuable, then just moved the ports or mabe even used the spacers as a port alignment tool ?
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Re: Pontiac Big Chief intake question

Postby shoedoos » Mon Apr 04, 2011 4:48 pm

I would think the spacer might actually be a combination of tall deck adaptor and also a valley plate.

Anyway, all those in the know, have a look at the photo below, apparently these are 427 castings. from what I see in the original photo and the port configuration below, the std BBC intake is either very close or not far off in layout of the ports. Or are you guys saying the spacing between the front set and rear set of ports is different? (apologies Bearcat, I have just read your earlier post and see what you mean)...would have been nice if a BBC intake could have fitted without too many mods....

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Re: Pontiac Big Chief intake question

Postby wizbang » Mon Apr 04, 2011 4:55 pm

The ports are much bigger ( wider ) and also the spacing between them is different. I think there is like .800 between the ports ?
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Re: Pontiac Big Chief intake question

Postby White Lightnin' » Mon Apr 04, 2011 9:42 pm

I stand corrected. Learned something new. Please forgive my stubborness!
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