FAQ |
Members List |
Social Groups |
Calendar |
Search |
Today's Posts |
#1
|
||||
|
||||
#96 head ?
Do 1971 #96 heads have hardened exhaust valve seats? Going to have a valve job done and going with new valve guides and the guy said new exhaust seats also if they don't have already..
Using new valves and springs.
__________________
1977 Trans Am,400 4 speed,numbers matching car 1979 Bonneville ,1 owner car... 1997 Trans Am convertible,LT1/auto. |
#2
|
|||
|
|||
the exhaust seats do not have the high level of induction hardening that later 4X-5C-6X heads do, thats from long time national Pontiac engine builder (45 years exp). Have a heavily worked pair of 7K3's, even though will be mixing some leaded race fuel in the tank, had hardened exhaust seats installed.
__________________
Buzzards gotta eat... same as worms. |
#3
|
|||
|
|||
General rule...All 71s in the industry got hardened seats.
(read it on the Interweb!)
__________________
"At no time did we exceed 175 mph.” Dan Gurney's truthful response to his and Brock Yate's winning of the first ever Cannonball Baker Sea-to-Shining Sea... Still have my 1st Firebird 7th Firebird 57 Starchief |
#4
|
||||
|
||||
I do my own valve jobs and I have run a casting number 96 with roller type solid lifter spring pressure needed to get a motor to 6500 rpm cleanly on unleaded fuel for 20K miles without issue .
I made my 30 degree Intake valve seat .065" wide and my Exh seat .080" wide so if your machinist can provide you with those numbers and you use stainless steel valves you will be fine and not need hardened seats installed on the Exh side. Make sure he does not apply a 3 angle valve job to the Intake , all you need is the stock 30 degree seat and .150" tall 60 degree bottom cut. On the Exh side to get that .080" wide 45 degree seat you will only beable to get a slight 60 bottom cut in there, and that's fine! Also have him apply a 30 degree back cut on your Exh valves to give you a remaining .080" wide seat on the valve.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#5
|
||||
|
||||
Ran a pair of 1971 #66 455 heads and after 30k miles the exhaust seats had recessed 1/8” or more on most of the chambers. 068 cam, Edelbrock 5857 springs and stamped steel RAIV 1.65 rockers.
I would advise getting hardened seat inserts installed.
__________________
1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#6
|
||||
|
||||
B man, please answer all of these questions in detail because they all add up to having good seat life or not.
And how wide where your valve seats on both the head and on the valves if they where used valves? Where they factory valves or stainless steel? How was your tune, on the lean side? What was your valve guide clearance?
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#7
|
||||
|
||||
1971 #96 heads will not have induction hardened exhaust valve seats.
GM had the induction hardening process in place across the board by the 1973 model year, not 1971. There were some 1972 heads that got hardened seats but as a general rule most will not have them........Cliff
__________________
If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
#8
|
|||
|
|||
Funny how people advocate the use of regular seats with unleaded gas
As soon as lead dissapeared from gasoline auto manufacturers hardened the exhaust seats They must of ran some tests and figured out there wasn't a problem with new valves new valve guides with correct carburetor calibrations reflecting a new production engine and decided to waste money on a useless feature anyway
__________________
A man who falls for everything stands for nothing. |
#9
|
||||
|
||||
according to Rocky's latest book, the hardened seats on OEM Pontiac cylinder heads was first done for the 1972 model year.
Even if no one else chimed in I would have said "no" to hardened seats for 1971 #96 heads.
__________________
1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
#10
|
||||
|
||||
The 72 7F6 heads I had redone for a recent 455HO build didn't have hardened seats in them. They do now
|
#11
|
||||
|
||||
The #66 heads I had were acquired from a friend. I took them apart to install screw-in studs then reassembled them after cleaning. They weren’t perfect and they weren’t completely worn out. Wasn’t running lean.
I think it’s wise to install hardened exhaust seats in any head you’re rebuilding no matter what year the head was manufactured, others may think differently.
__________________
1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#12
|
|||
|
|||
As a data point was there any 1.77 exhaust valve heads with hardened seats ?
__________________
A man who falls for everything stands for nothing. |
#13
|
||||
|
||||
Yes the 7K3 heads and 7F6 heads we have done had induction hardened seats. The SD-455 heads came with an exhaust seat insert.
|
#14
|
||||
|
||||
Don't think that I've seen a set of stock 96 heads that didn't have some recession going on. They did good and made it past 100,000 miles or so, but the party's over.
Not that much extra money just to go ahead and get it done.
__________________
Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon in progress. |
#15
|
|||
|
|||
Note that the factory hardening was not a separate seat of a different material that was pressed in. Factory hardened seats were either "flame hardened" or "induction hardened." The "flame" hardening was the first technique used, in '72 I believe. It didn't impart as much hardness into the seats so they went to the induction hardening.
Basically the factory used high heat to harden the metal in the heads at the exhaust seat. Once those seats start to wear, it makes sense to put new hardened seat inserts in.
__________________
---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
Reply |
|
|