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#1
05-16-2018, 11:40 AM
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670 or 16's
What head is better 670 or 16? Thanks
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67428HO |
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#2
05-16-2018, 12:16 PM
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In stock form it's a bit of a toss up!
The 670 Intake port flows better at low lift then the 16 , but the 16 chamber needs less timing and has a faster burn rate.
__________________
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! |
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#3
05-16-2018, 12:25 PM
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Sorry to butt in, but would that mean the 16's would be better with a higher compression engine??
Dave |
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#4
05-17-2018, 05:17 AM
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If you are not planning on making any modifications to the cylinder head combustion chamber on the 670's then use which ever one has the best chamber size for your target static compression.
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Tim Corcoran |
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#5
05-17-2018, 05:56 AM
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The open chamber of the 68 and up heads are bit more sensitive to lean conditions and hence pinging.
__________________
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! |
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#6
05-17-2018, 02:04 PM
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67428HO, I happen to have a set of 670 heads rebuilt and ready to go fo sale if you need a set.
Just sayin’ Sent from my iPhone using Tapatalk
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Let me have a Diablo sandwich and a Dr. Pepper and make it fast---I'm in a goddamn hurry! - Mike 1967 GTO 
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#7
05-17-2018, 02:14 PM
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If i had no heads in front of me and was shopping and those were my choices i would pick whichever had the least amount of previous valve jobs or pick the virgin set
Other than that late model heads like 6X have some accessory holes earlier heads dont have depends on your needs there
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If your not at the table you're on the menu A man who falls for everything stands for nothing. |
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#8
05-17-2018, 04:40 PM
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I have a single 670 head with the manifold still attached, what's it worth?
__________________
“Nothing in the world can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan Press On! has solved and always will solve the problems of the human race.” ― Calvin Coolidge |
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#9
05-18-2018, 06:06 AM
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I also should have also mentioned that if you live in a state with emission testing then passing such will be easier with the # 16 heads!
__________________
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! |
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#10
05-18-2018, 02:14 PM
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Thanks for the info. I think I have a head gasket problem. I figured since I have to pull the heads off, which are 670 's I would get valve job done but wasn't sure if they're any better or worse than 16's.
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67428HO |
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#11
05-19-2018, 06:20 AM
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A valve job is never just a valve job once you get 50 year old original head off a motor!
In the least plan on stuffing in a few guides, a few valves, cutting all 16 guide tops for seals and replacing the valve springs.
__________________
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! |
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#12
05-19-2018, 07:24 AM
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I planned on going through them. New valves ,seals,etc.
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67428HO |
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#13
05-19-2018, 01:37 PM
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I’m curious about this too. I wanted to use a set of 16’s on my 68 Firebird. Just to make it look more correct. But kept getting beat to the punch when I tried to buy some. So I ended up using the 670’s that I already had. So far so good. Should be a mid 12 or better car if we can get some traction. Engine is temporarily in my son’s 79 TA. Strangely though, it seemed to make its best power on dyno with 34 degrees timing. Was thinking it would be higher. Oh and we did have an issue with the missing hole on the head for the long bolt for alternator
Sent from my iPhone using Tapatalk |
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#14
05-20-2018, 06:43 AM
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Well besides the chamber shape effecting the full throttle max power timing needed the piston speed ( bore to stroke ratio) and how it relates to cylinder pressure rise is a big part of the total timing picture as is the Cam overlap spec and where the Intake valve closes.
__________________
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! |
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#15
05-20-2018, 08:27 AM
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I'm in the same boat as Dave M, not a number's matching car ,but it is a 68. I wasn't sure about the closed chamber vs open chamber. Looks like the 670' s will work OK. It's not a race car, small 450 ish lift hydraulic Ultra dyne cam. Figured since I need to have them reconditioned, now would be the time to swap if necessary. Thanks
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67428HO |
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#16
05-20-2018, 02:20 PM
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Quote:
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2001 Trans Am,WS6 Sunset Orange Metallic (sold) 1973 Trans Am 455,4speed 1970 GTO |
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#17
05-20-2018, 05:28 PM
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I think most base 4bbl 400's were at 335hp a 350hp would get slightly more compression and a 068 cam vrs 067 cam
But there was alot of numbers fudging going on back then
__________________
If your not at the table you're on the menu A man who falls for everything stands for nothing. |
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#18
05-21-2018, 06:19 AM
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The open chamber heads shape places the spark plug much more in the center of the chamber then the early heads, and this makes for a faster burn rate and greater power from the same amount of fuel and air.
__________________
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! |
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#19
05-28-2018, 07:41 PM
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ratings
Does anyone 'really' believe the factory horsepower ratings? Do you also believe what politicians say?
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#20
05-29-2018, 06:06 AM
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The factory gross hp ratings are a bit happy, but I believe the diffferrnces in hp between let's say for example a 1969 400 4 bbl base line model rated at 350 hp and the RAIII model at 366 hp are correct.
__________________
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! |
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