# 16 vs 62 heads?



## 58mark (Sep 28, 2010)

Can somebody tell me the difference between the 1969 62 heads and 1970 16's?

I'm looking at a 1970 factory 400 Lemans that has had a head swap, and I'm trying to figure out of that's a good thing or a bad thing, or just a thing.


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## 58mark (Sep 28, 2010)

nobody?


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## Pinion head (Jan 3, 2015)

'70 model 16 heads are small valves approx 78-80 cc chamber heads. "62" s were used on many '69 400 4bbl engines, but not '69 WT 400 applications or RAIII GTO applications. Virgin w/o valves sunk bad, chambers should cc between 72-74 cc.

On '70 model 400's one will find the 16 small valve press in stud heads on the 400 XV coded engine which was optional in Tempest/T-37, LeMans, & LeMans Sports. This 400 4bbl engine was rated with 330 hp, advertised 10-1 CR. This 330 horse 400 4bbl was offered basically to keep from being noted by the insurance industry as a vehicle with under 10-1 weight to hp ratio. With a 3 spd or 4 spd ordered, these same 400 4bbl vehicles received the WT coded 400 with casting 12 big valve heads. 

Both the factory XV 400 installs, as well as factory-installed 400 WT engines in non-'70 GTOs are rarely seen anymore. In the '90s, I passed on a number-matching 400 XV GT-37 project car in Amarillo. Atoll blue with black bench, the GT-37's rear 1/4's were scraped bad along the crowns of the 1/4 panels& both quarters would need replacing. That was a really dumb move on my part, just did not have room for it at the time.


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## 58mark (Sep 28, 2010)

you'll have to forgive my lack of knowledge on your terminology. 

when it is all settled, forgetting originality, which set of heads is more desirable, and why?


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## Pinion head (Jan 3, 2015)

Value...all depends on what the car is, or if you are trying to sell a pair of core heads. I have several pairs of "62"s as well as '68 model big valve "16"s, neither casting go for big money as cores, but core wise they are worth more than any '69-70 small valve heads. 

If was in a position to need a pair of '70 model "16"s, there are several local yards where ive been through shelves & shelves buying all the 6x-4's, etc, & there are still many small valve heads from '69 & '70 engines. If I'd picked up that '70 1/2 GT-37, and rebuilt the engine/was planning to keep it original looking under the hood while picking up a little performance & was planning on going with more rear gear, I would have had the original small valve 16 casting heads rebuilt with 2.11/1.77 stainless valves & had the heads converted to screw in studs.


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## 58mark (Sep 28, 2010)

Like I said. I'm looking at a car that should have 16's, but it has 62's instead. Trying to figure out of that's a good thing or a bad thing, or just neutral

Somebody in the past made the swap, and I'm trying to figure out why


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## Pinion head (Jan 3, 2015)

sorry, was mad dash to get trailer unloaded, lot of rain came through. my thought, plus or minus is going to depend on what the car actually is. You note it's a '70 LeMans. Is that a 235 series LeMans or a 237 series LeMans Sport? Is it a 233 series car? 

There was a red '70 400 auto GT-37 project for sale in the N central Metroplex area, the guy used to list it on Dallas Craigslist & I believe EBay, car needed a ton of work, believe it had original 400 XV block... it was def a 400 auto car. On that particular car, yes, it's mighty rare, but my thought, the guy was too high on his asking price. As a longtime GT-37 restorer & as a collector, if i owned that '70 400 auto GT-37, I'd want a date code matching set of 16's on the original XV block. A set of 62's or say 13's, I'd be pulling them off if the project was mine, in decent core shape the '62's are worth $300 - 350, maybe 400. For the price return from selling them, could then get a pair of nice core correct dated 16's & get work started going through them @ my machinist. Let's say the car was a really nice color combo '70 LeMans Sport convert that was in fairly clean condition, didn't need a lot to be a really clean original appearing car, again the "62"s are not doing anything for me value wise on the finished car. On the other hand,, let's say the car started out as 350 2bbl car, or it's a rough 23537 LeMans hardtop which though optioned as a 400 4 bbl car, was not ordered in a very desirable color, & the stock 235 series interior is trashed (no correct repro interior pieces, in that case). If that is what I'm looking at, it's no big deal there are a pair of 62's under the hood on a 400, if im buying it, im buying it priced cheap, not to properly restore, & the car is prob going to get the Hotrods to Hell treatment, just needs a big kid to buy it. Hope this helps.


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## 58mark (Sep 28, 2010)

it's a factory 400 lemans sport. Nice condition, but not 100% factory original, and That doesn't bother me. I'm more interested in the implications of the head swap as far as performance goes. (not that I intend to race it, but I was wondering if the change to the 62 heads were made from a performance angle

I'm probably going to put a GTO hood on it, and maybe a couple other mods that aren't factory original. I am getting a LeMans instead of a GTO, because with a GTO, I would feel like I had to leave it original. I consider a Lemans a bit more of a canvass that I can work with


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## bigD (Jul 21, 2016)

IMO the #62 's are more desirable, from a performance standpoint, because of the large valves, screw-in studs, and maybe 72-75 cc chambers. (those numbers vary).

As said, the small valve 16's can be converted to big valves and screw-in studs. Many also consider it a very good idea to add hardened valve seats, for use with unleaded gas. 

If mine, I'd probably go with small chamber 6X or 5C heads, or even the screw-in stud version #46 heads, such as came on the '74 GTO. I'd try to get the CR above 8.5 and run a mild Voodoo cam, to increase cyl pressure. Obviously there are ways to make more power. Just depends on what you want. 

If you run the older heads, I'd try to keep the CR below 9.5:1. Might require a small dish in the pistons. But there are other ways to lower CR slightly. 

If you rebuild the engine, don't use the cheap "8-eyebrow" 400 rebuilder pistons. They have a lot of sharp edges, and are known to help cause detonation. They also have a short pin height, which means a bigger cut off the block decks will be needed to get near zero deck height. 

The cheapest forged pistons are the L2262F Speed-Pro units. 

Well, that's more info than you wanted. Sorry. 

Good luck with the car !


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## 60sPontiacs (Jul 14, 2016)

Found this thread while searching for difference between '68/'69 16 and 62 heads (cleaning up garage and found several).

I agree with BigD. No telling why previous owner swapped them... wanted bigger valves, higher compression? problem with originals and upgraded? Could be PO found a set of fresh 62s for less than it would cost for a valve job and reworking the '70 16s into big valve/screw stud heads. The only downside is compression's a bit higher with 62s so you need better gas. Rough CR estimates for stock bore 400 for 72/75/78cc are 9.84/9.56/9.30:1.

A guy on ebay has some clean/checked '70 #16 78cc castings (not cheap). These might be good for someone wanting to make their engine original. Big valve 16s seem common.
https://www.ebay.com/itm/Pontiac-cylinder-heads-16-/253353119967

Nice car.

And thanks BigD for info about pistons. I bought a used 400 engine that has the "8-brow" pistons (KB silv-o-lite 1526-030) - leak down great, engine's good. No detonation with 670s (10cc of valve relief and .025 down in hole, CR calcs 9.55:1, 10B init) using 91 octane, but I just got it together and it's cool here in winter.. car only gets to 140F after 20 mi 75mph run on hiway, but that's for another thread... I read that Jim Hand used TRW (SpeedPro?) forged pistons in his 455 (the one that dropped a carb screw) with stock rods which surprised me because shop guy here says they're too heavy... but an engine like in Jim's '71 wagon is all I'd ever want for street. Uses #64 87cc ('70 455HO) heads to get 10.2:1 (which says runs on 92 octane Amoco). Much to learn about that engine.
Jim Hand's 455 Pontiac Power


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## cij911 (Oct 25, 2017)

I read the big valve, screw in studs 16 heads were some of the best flowing heads around...



60sPontiacs said:


> Found this thread while searching for difference between '68/'69 16 and 62 heads (cleaning up garage and found several).
> 
> I agree with BigD. No telling why previous owner swapped them... wanted bigger valves, higher compression? problem with originals and upgraded? Could be PO found a set of fresh 62s for less than it would cost for a valve job and reworking the '70 16s into big valve/screw stud heads. The only downside is compression's a bit higher with 62s so you need better gas. Rough CR estimates for stock bore 400 for 72/75/78cc are 9.84/9.56/9.30:1.


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## 60sPontiacs (Jul 14, 2016)

I saw that on a forum yesterday, but forget which one.

Found this again after reading it long ago. 
The Ultimate Pontiac Head
Wallace compares many heads and comes up with his opinion (disclaimer at beginning says take his flow numbers with a grain of salt, but he was consistent with his testing). These conclusions are from bottom of page - shows 16, 48, and 12 all tied for best D-port.
Best performance head 1970 Ram Air IV
Best intake port 1969-70 Ram Air V
Best exhaust port 1 968 1/2 Ram Air II
Best D-port head No.16, No.48, No.12 (tie)
Best low-compression D-port head No.96(1971)
Best low-compression post-1972 head No. 6X
Best balanced head (exhaust to intake) 1963 421 SD
Best low-lift (under .400) head 1967 No.670
Worst exhaust-to-intake port ratio 1969-70 Ram Air V
Worst intake-to exhaust ratio 1968 1/2 Ram Air II
Biggest surprise Intake port, No.17 350 head
Biggest disappointment 1969-70 RA V, 1973-74 455 SD (tie)
Biggest "sleeper" 1975 No. 5C
Most undercammed 1963 SD, 1971 455 HO, 1973-74 455 SD (tie)
Most underexhausted 1964 GTO (No.9770716)
Most potential for porting 1973-74 455 SD, 1968 1/2 RA II (tie)


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## PontiacJim (Dec 29, 2012)

Basically, all Pontiac D-port heads with the 2.11" intakes/1.77 exhaust flow pretty close the same. Funny how the Ram Air V gets the worst exhaust-to-intake port when it was capable of propelling a '69 GTO down the quarter mile at 11.73. Ya, I'd take that poor port any time. 

So read the numbers with a grain of salt as he says. A little gasket matching, port work, and cleaning up and they all flow pretty close unless you do major work on them.


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## tjta (Jul 24, 2020)

Hi Everyone. Need some in depth advice about the 62 heads from a 1968 Pontiac. I may need to change to this head from a 4x head. My brackets for my alternator and power steering currently work with the 4x heads. Will I have issues using my alternator and power steering brackets using the 62 heads? Will everything line up properly? I have read some where that it might be a problem. I thought it was all standard with respect to the bracket fitment.
Thanks


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## PontiacJim (Dec 29, 2012)

First, why do you want to change the heads? 

Second, look at the front of the head and match the bolt holes from one head to the other. From what I have read, the #62 heads (1970 and earlier heads in general) won't have the needed bolt holes for the later brackets. You may have to source brackets and/or pulleys.


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## tjta (Jul 24, 2020)

Thanks for your reply. Apparently, according to the builder, someone had put in exhaust seats and when the machinist removed the seats they found that it was welded. They are not cracked but welded in that area(s). The builder stated " we are not going to use those heads ". He has come across a pair of #62 heads and are "virgin" that will be checked out as well ( cleaned and mag ) prior to building it back up. 

I have read that some people have done some makeshift brackets. I don't know how much of a problem makeshift brackets will cause ( reliability wise ) if I decide to go ahead with the #62's. 

Should I look for different heads from 1970 and later?


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## BearGFR (Aug 25, 2008)

Date codes, date codes, date codes, date codes! 
There were heads with casting number 16 in 1968, 1970, 1973, and 1974. #16's in 1968 had big valves and screw in studs, and were for all practical purposes identical to the 1969 #62's. In 1970 16's had smaller valves. In 73, and 74... well if you've got those then you're sitting on a pile of cash there. Those are 455 SD heads.
If you want a positive ID on heads or a block, always start with the date code to ID the model year. For heads, the date code is most often "inside" under the rocker covers.

Bear


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## tjta (Jul 24, 2020)

They were from 1968. All I was told today is that it is #62. 

My concern is with the accessory brackets, ie. Alternator and Power steering brackets bolting onto the head. I have read that the top hole is missing for the alternator bracket on the 62's. My 4X's had them though. 

I was looking to see if someone had the same issue and what was done about it to make it work. Makeshift brackets will probably look silly and the reliability is questionable at best in my opinion.


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## Jared (Apr 19, 2013)

They sell re-pops of the original brackets that would work with the older heads. Check out Ames. Since you were running a set of 4X I'm thinking your power steering bracket is cast (I think aluminum) and bolts to the front of the head? Another option would be using later model head that would have the holes in the right place rather than the older heads that do not. 6X and 4X heads pop up for sale all the time. Ebay has a bunch of each. Too bad you're not closer, I would give you a great deal on the 4X heads that I just pulled off mine.


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