Who knows...maybe they figured the world was ending and we'd all start building Mad Max style vehicles with huge blowers and they were just preparing for the worst?
The 4X,5C,6X had 94 ccs to 102 and the 455s had around 118 . Just going by memory. The 94 cc are pretty good on 455s. I run 72 cc heads on all my 400s and thats just around 10-1 which you can run with pump gas with the factory flat top pistons and the fully machined chambers. Check this video out. This is with the stickiest street tires money can buy and if I'm in first and floor my car, it frys tires on demand even if you are just cruising at 20 mph. I actually prefer the 72 cc heads over any other head on a 400. Check it out. The bottom end is stock and so are the heads without any port work. This is why I love Pontias soooo much. Its a few seconds into the movie. The car isn't traditional but the driving is. LOL. http://www.youtube.com/sixt8bird#p/u/5/6dTfMAH9UL8
The valves after 1972 became 2.11 x 1.66 inches on most heads. The performance heads from 1967 to 1972 were 2.11 X 1.77 inches. Most 4X had screw in rocker studs , the 5Cs were all screw in rocker studs and so were the 6Xs, if you went to a high pressure spring, the BB Chevy 7/16" rocker studs screw right in. The hot ticket use to be to use the 96 heads from 1971 or the 7K3 Heads from 1972 as they would yield a little over 9-1 but had the 2.11 X 1.77 valves. The 7K3s didn't have the end bolt holes for the exhaust so were prone to leak unless modified when using headers.
Of course! When I stopped the car, Steve Apple switched with me. One of the most fun times I have had. Even when the cops came!!!!!!!. The pavement was black but luckly I broke a belt and was re installing the one belt when they pulled up. I was dressed like Steve at the time with the whole get up and the cops asked us what we were doing. I told them that we were shooting a movie and thought that this was a good spot as it was out of the public harms way. he then asked us if any of us worked for the school board. Clueless we all said "No why"? The said that the property belonged to the Everett School board. Wholy shit!!!! Here we are during the week doing huge donuts on school property at 1:00 PM during school hours!!! This is the Aquasox stadium. Who would have thought it was school property. I said we had no idea and we will definately get permission if we needed to do it again but I think we should just call it a day and go home. The cops agree'd and left. We then had to find another spot to do the last take where Al Braughtonwood (Steve's character)gets out of the car. We filmed him getting out of the car first and all the other takes so I could come around the corner, stop the car and then say goodbye and get the hell out of Dodge. Very fun day!!!! The tires are MT ET Drag Radials 275 60 15s lowered to about 20 lbs. After that day I used up about 1/2 the tread but I was good with that as I was "IN A MOVIE"!!! I actually gave them a choice of my Convertible 400 4 sp, or my other 400 coupe thats the same color as my Convertible. They chose the beater even though I'd have driven my other cars just the same as I do anyway.
I really gotta look up the heads from the '71 350 again, I think they just need the bigger valves and screw in studs...I'm almost positive the studs on my '76 6X 2bbl heads have push in studs though...if they have screw in studs, then maybe I'll just use the 6X's and buy some pop-up pistons to raise the compression...I want to stay in the 9:1 or 10:1 comp ratio range to be on the safe side for my pocketbook...
No it is not, as the boss is missing. You need to build up the metal then tap or they sell a clamp that I dont think would work that well. The two end bolts are real short as the head bolt goes through vertical and the exhaust bolt intersects it horizontally. Even when the boss is there, there's only about 1/2" of thread max.
R U sure? The few I've seen with no holes still had the flat, machined surface to drill with no issues. And 1/2" is plenty. A bolt is no stronger than it's diameter. 3/8 bolt 1/2" hole should be fine
I just went out in the garage and looked at a set of heads I have. There's a "solid" 3/4" of thread before the end bolt intersects the head bolt
After 12 years of having those stupid equations beat into my head, I can't even remotely try to forget them...unless, of course, I NEED to remember them ...then it's like I'm a retard in the middle of a tapioca filled swimming pool, all I can do is look around and drool...
The head does not have the boss and it will leave next to nothing if you tap it. I am sure of this, thats why they make an aftermarket clamp. If it was such a simple fix they wouldn't sell it. I have modified a couple sets and like I said, I prefer the sixties big valve on the 400 and as far as making power, I have a couple sets of Edelbrocks. I'm done with the cast iron heads at this point in my life as out of the box Edelbrocks outflow any modified cast head.
48s and 16s are so close to each other, I'd like to know where and why the 16s would take more work to make as much power. I have had a set of 16s and 48s side by side and visually, they look the same. In the flow tests done in the mags, the 48 barely outflowed the 16s but that could be due to worn guides etc. The 2 bbl #17s from 1968 350s had a better intake flow than the 48s. Go figure. They are small valve heads.
Thats not a pair of 7K3 heads you measured is it. OK Groucho, I called your bluff and measured 4 sets of heads. All the stock heads have 1/2" total" meat before the head bolt hole not 3/4". When the boss is missing, that leaves 1/4" . I checked out my 16s, 4X, 96s, and last but not least my early 1960s 421 heads. They all measured the same. The 421 heads are not the desirable ones so I use these to sit on my aerator for weight. LOL. By the way, I was president of our Firebird club for 2 years with over 200 members at one time and was the go to guy for working on club members cars that didn't have the skill or know how. Even the guys that do know quite a bit call me and ask me to help them when they can't figure something out even though I'm no longer the President, The new president always refers me to them. I still help my Pontiac Brothers out for free. I am now working on my Hemi and doing a ton of mods to the engine. I love thinking out of the box and thats why I am more into the hotrod stuff as it gets your mind thinking creatively. Making parts for a 58 year old engine is cool and totally different than a Pontiac.!! I have pretty much read every bit of Pontiac literature that has been written.
I know we got off on the wrong foot, and I was pushing your buttons last night, so I apologize for that...and I'm not getting back into the numbers you got out of those two motors, so I'm going to drop that...but, there's absolutely nothing wrong with learning through books or online from others' experience to minimize our own mistakes on the way to making power in our own projects...
Oh, and after seeing the gains those Edelbrock heads made in the HRM article, I've actually been thinking of scrapping the blower idea and invest in new or used Edelbrock aluminum heads...they're not "traditional" since they're a new product, but it damned sure beats dicking around with cast iron heads, and drops 50 pounds of weight between the heads and intake...I'm going to use my cast iron heads for the time being, but you can bet I'll drop the coin on aftermarket heads as soon as I can get the chance to...
The heads with the missing castings for the end bolts appear to be 1972 only in my experience. 7K3 has all the good features except for the bosses for the outer bolts. However, you may or may not need them. In 1992, I built a 12 second '70 GTO and drove it work everyday with 7K3 heads and headers. Raced it at Firebird here in Phx area. I just did not use the out bolts because there was no place to bolt them. Surprisingly, I did not leakage problems with the header gaskets. Other years had the casting in place but not drilled ( those were low performance heads). Many aftermarket heads out there now In the modern era. Wenzler was first, then Edelbrock ( they have 2 more Pontiac heades coming out soon ). AllPontiac.com sells the Tiger heads, Kauffman sells d ports, high ports and will make custom Ram Air V or HEMI heads. Jim Sammonds of Roland racing in Mo makes the canted CV-1 head. Plus there is reportedly others tolling up for V heads for those who want them. Pontiac did make some alum heads in the early 60s. Not used in production. I had a pair in the late 80s. M/T made alum HEMI heads in '62, I have 7 of these casting including 2 that are on a complete M/T HEMI Pontiac engine. Lots of neat parts for Pontiacs out now. these are good times to build any kind of Pontiac. Steve Hosting- 12th annual Pontiac Heaven April 8-11, 2010 Phoenix www.pontiacheaven.org 8th annual Nostalgic Show & Go! April 11, 2010 Phoenix www.nostalgicshowandgo.org
No, they're 1966 GTO heads I think. I didn't look at the number. BTW, it wasn't a bluff. I measured the only Pontiac heads I have
I've never heard negative feedback that the L bracket doesn't work as designed, have you tried it and not had good results? http://www.spottsperformance.com/headLbracket All i've ever used on my 428 and 389 was 670's so no need for me to use it.
Comparable Kauffman heads are good but limited. They are still a D port but have the the more modern heart shaped chamber. The Edelbrocks still make more power. The nice thing about Pontiac now is that so many people are designing better heads and parts to keep up with the competition. The Canted valve heads I believe have been released at this time. Kauffman and All Pontiac are some of the great investors in our little Pontiac world. Check out Kauffmans link. http://www.krepower.com/KRE_billet_aluminum_heads.htm Roland Racing also has a Canted valve design.
My thinking is that the heating and cooling of the clamp would end up failing after time. Plus who would want 4 clamps sticking on your head. Just heat up the head, weld the boss on and drill and tap. Do it right.
Steve, you and I are on the same page but a few posts ahead or behind each other LOL!!! I just went back and read your post here and I just mentioned what you mentioned on the last post. Geeez. You took the holeshot!!
HMMMM, I've never seen or heard about those clamps til now. So, the clamp is ONLY for the 72 head? If so, I'm impressed anyone went to the trouble of making the clamps for just one particular head. BTW, is 72 the year or the number above the exh port?
What are the price ranges for some of these aftermarket aluminum heads? Can anyone list who's most expensive to the least expensive in order? Do all of them come bare or loaded? I'm not able to see some of the websites for these heads, but I'm curious about which heads give the best bang for the buck in my situation...thanks...
I only know a fraction of what some of these guys know about Pontiacs (great stuff to learn here BTW). But, if I had to guess, because of higher production capability, it would almost have to be Edelbrock. You did say most bang for the buck, and not the best head, right? They are available complete. I think they're around 16-1700 dollars
They are just a simple piece of angle metal. The 72 is the year and 7K3s are on the center exhaust port.
I'm half tempted to blow my entire rebate check from buying my house on a stroker kit, a pair of heads, solid cam, forged pistons and machining...but there are SOOO many other things I can do with 6 grand especially if I were ever unlucky enough to blow it up somehow...it might be better for me to stick with my original plan of the 450lb ft 375hp el cheapo 406ci build...
The Jalopy Journal
