G'day,
I have just picked up a 308 which I will probably be stroking to 355, it came with some heads that have been throated out and had 1.94 and 1.6 valves fitted but they have not been ported, I am just after some guidance on what to do, as I have heard that 308 heads should be ported differently to most other heads.
I can post up some pics of the ports/bowls if it helps
cheers,
Cohen
porting pre VN V8 heads
Started by
makka
, Oct 10 2008 07:39 PM
60 replies to this topic
#1
makka
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Posted 10 October 2008 - 07:39 PM
#2
_threeblindmice_
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Posted 10 October 2008 - 11:33 PM
Maybe give Superflow Sydney a ring ,they have been doing heads for 30 years.
#3
_greenmachine215_
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Posted 11 October 2008 - 01:02 AM
If it were me, id port them straight to the bin and get some VN Heads with a harrop single plane manifold,
The amount of porting involved to get them to flow anything close to a VN Head would be phenomenal, needless to say the cost,
From what ive seen the vn heads flow awesome, and the stock valves apparently can handle upto 450-500hp,
The amount of porting involved to get them to flow anything close to a VN Head would be phenomenal, needless to say the cost,
From what ive seen the vn heads flow awesome, and the stock valves apparently can handle upto 450-500hp,
#4
_ChevLX_77_
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Posted 11 October 2008 - 09:15 AM
Im with greenmachine if ya gonna do a 355 you may aswell do the VN heads aswell
#5
makka
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Posted 11 October 2008 - 01:24 PM
I know that I will make more power if I go VN but I have these heads here already so I am going to port them and see how they go. I also like the fact that it will look pretty stocko with the old style heads 
#6
TerrA LX
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Posted 11 October 2008 - 02:01 PM
^^ Depends on what RPM you compare them at.
#7
_greenmachine215_
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Posted 11 October 2008 - 10:00 PM
Makka, Put it like this.
You finish building the engine, it puts out a bit of power with the heads you have on, I Guarantee you will get hungry for more power, then you'll start thinking about putting on the VN Heads, Then theres more work more money and less driving time.
I was in the same boat 2 years ago with my hatch, thought i could make a 253 go like a rocket, Everyone told me not to bother, id get more power from a stock VN 5.0 here i was 5grand later and still didnt get figures of a stock VN 5.0 And that had Yella terra Old cast heads big cam the lot
6months later out come the motor and im now doing what i should have done in the first place,
Im not telling you what to do, no one here is, But thats just my advice. If your laying down some decent coin for a tough bottom end it would be worth just putting in the extra few hundred and know that your getting the most outa your engine.
You finish building the engine, it puts out a bit of power with the heads you have on, I Guarantee you will get hungry for more power, then you'll start thinking about putting on the VN Heads, Then theres more work more money and less driving time.
I was in the same boat 2 years ago with my hatch, thought i could make a 253 go like a rocket, Everyone told me not to bother, id get more power from a stock VN 5.0 here i was 5grand later and still didnt get figures of a stock VN 5.0 And that had Yella terra Old cast heads big cam the lot
6months later out come the motor and im now doing what i should have done in the first place,
Im not telling you what to do, no one here is, But thats just my advice. If your laying down some decent coin for a tough bottom end it would be worth just putting in the extra few hundred and know that your getting the most outa your engine.
#8
_waz355_
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Posted 11 October 2008 - 10:17 PM
Yeah I agree. Not worth spending the money for porting 308 heads when you could bolt a set of stock VN heads on and use your porting money to go towards a manifold and extractors.
You won't regret it, whereas if you use those heads down the track you will regret it.
Another thing. I have a 355 with alloy heads and have had a 333 stroked 308 with cast heads hogged out and went to standard VN heads later on. The 333 with cast heads (with a lot of money spent on them) made 260bhp and with the VN heads it made a fraction under 290bhp.
In my opinion the smaller strokers are a much better engine they rev a lot nicer and are not a lot different in the power figures if set up properly. They are not quite as torquey, but if I built another holden stroker I would build another one of them.
Anyway thats my take on it. Good luck with it!
You won't regret it, whereas if you use those heads down the track you will regret it.
Another thing. I have a 355 with alloy heads and have had a 333 stroked 308 with cast heads hogged out and went to standard VN heads later on. The 333 with cast heads (with a lot of money spent on them) made 260bhp and with the VN heads it made a fraction under 290bhp.
In my opinion the smaller strokers are a much better engine they rev a lot nicer and are not a lot different in the power figures if set up properly. They are not quite as torquey, but if I built another holden stroker I would build another one of them.
Anyway thats my take on it. Good luck with it!
#9
mr5000
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Posted 12 October 2008 - 09:25 PM
i did my heads my self got a carbide bur die grinder and went nuts goes alright now
#10
_ChiaLX_
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Posted 13 October 2008 - 09:54 AM
makka try Eugene from flowcraft heads in deerpark. He actually steered me away from vn heads for a mostly street driven car. he did me a set of hq's on a standard stroke 308 that should get me to low 12's which is fine for what I want. this will be found out in the next few months after I sought carby and dizzy probs.
there are plenty of hq headed cars thats still get in the 10's, but unsure of how much work needs to be done to them.
there are plenty of hq headed cars thats still get in the 10's, but unsure of how much work needs to be done to them.
#11
yel327
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Posted 13 October 2008 - 11:18 AM
Holden won Bathurst in 1975, 1976, 1978, 1979, 1980, 1982, 1983, 1984, 1986 and 1987 running early heads, and apart for some rotten luck could have won 1974 and 1985, plus 1981 didn't go the full race distance. Not a bad track record for a head design. I can't disagree with greenmachine's logic though.
#12
myss427
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Posted 13 October 2008 - 11:45 AM
You can't beat better the designed heads for ease of performance, the amount of time and money you need to spend to get the old heads up to where the VN heads are now would be huge. Plus as has been said when you want more, you'll have to change!
#13
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Posted 13 October 2008 - 11:46 AM
Sorry double post!
Edited by myss427, 13 October 2008 - 11:48 AM.
#14
MRLXSS
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Posted 13 October 2008 - 12:22 PM
I think Makka wants to just play with these old style heads. Its not going to cost him anything (He already has them, and they already have big valves in them)
So there is no harm in him having a "play" with them to see how well they go. If he wants VN heads, he needs to spend money on Heads ($300), Manifold ($500), Extractors ($500) and he still hasnt started doing anything and he is already $1300 behind?
If he can do all the work himself on the heads, It might cost him $100 for some dremel parts and a few hours labour! So he is $1200 better off... There is his 355 Crank!!!
I know what i would rather do!
As yel327 has said, the old style heads aren't that bad... They have a good track record!
If he wants to upgrade later on to VN heads, He knows that he has already exhausted all options with the old style heads and got the most he could out of them!!
So there is no harm in him having a "play" with them to see how well they go. If he wants VN heads, he needs to spend money on Heads ($300), Manifold ($500), Extractors ($500) and he still hasnt started doing anything and he is already $1300 behind?
If he can do all the work himself on the heads, It might cost him $100 for some dremel parts and a few hours labour! So he is $1200 better off... There is his 355 Crank!!!
I know what i would rather do!
As yel327 has said, the old style heads aren't that bad... They have a good track record!
If he wants to upgrade later on to VN heads, He knows that he has already exhausted all options with the old style heads and got the most he could out of them!!
#15
_moot_
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Posted 13 October 2008 - 01:50 PM
i think you need to adjust your prices a little 
even if you got the old heads for nothing,they'll still need reco and valve springs (theres $500) and there still shit heads.why spend money and time that you dont have to, porting the guts out of something that can be replaced by cheap bolt-on parts.
2 old motors with vn heads i've had:
355 9.2:1 comp, stock vn heads,redline manifold,235@50 cam=427hp (engine dyno)
355 11.4:1 comp,pocket ported vn heads,tp manifold,crane 288=505hp(engine dyno)
holden power is cheap and easy with vn heads.
even if you got the old heads for nothing,they'll still need reco and valve springs (theres $500) and there still shit heads.why spend money and time that you dont have to, porting the guts out of something that can be replaced by cheap bolt-on parts.
2 old motors with vn heads i've had:
355 9.2:1 comp, stock vn heads,redline manifold,235@50 cam=427hp (engine dyno)
355 11.4:1 comp,pocket ported vn heads,tp manifold,crane 288=505hp(engine dyno)
holden power is cheap and easy with vn heads.
#16
makka
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Posted 13 October 2008 - 09:02 PM
Matty hit the nail on the head although moot makes a good arguement.
basically the heads cost me nothing, I will be porting them myself, I was mainly just looking for someone to point me in the right direction on how to do the short side on them
whats the going price for a set of VN heads these days?
basically the heads cost me nothing, I will be porting them myself, I was mainly just looking for someone to point me in the right direction on how to do the short side on them
whats the going price for a set of VN heads these days?
#17
_rorym_
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Posted 13 October 2008 - 09:39 PM
$400-600. Cheap performance. Flow more stock than a well ported set of earlies would on their best day.Sorry guys...with Moot on this one...its a no brainer... My 2cs
R
R
Edited by rorym, 13 October 2008 - 09:40 PM.
#18
_rorym_
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Posted 13 October 2008 - 09:44 PM
If it were me, id port them straight to the bin and get some VN Heads with a harrop single plane manifold,
The amount of porting involved to get them to flow anything close to a VN Head would be phenomenal, needless to say the cost,
From what ive seen the vn heads flow awesome, and the stock valves apparently can handle upto 450-500hp,
Listen to the Green!! Listen to the Green!!..(Not Talk to the hand this time!!)
R
#19
_TJ253_
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Posted 13 October 2008 - 09:46 PM
You can pick up VN heads for a couple hundred on ebay
The most expensive part changing to VN heads is the Manifolds
The most expensive part changing to VN heads is the Manifolds
#20
_Lostit_
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Posted 13 October 2008 - 09:48 PM
vn heads flow 440hp with largest exhaust valve alrdy . standard factory
To get red heads flowing those numbers or better you going to spent a little bit more
To get red heads flowing those numbers or better you going to spent a little bit more
#21
_ChevLX_77_
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Posted 14 October 2008 - 06:49 PM
Porting early heads is an art as i have been told that you need to port them diffrently to any other head to make them work. For some info pickup Street Machine from september this year and read Stage Write, has a little bit of info. I to will be taking to a set shortly, let you know how i go
#22
_rorym_
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Posted 14 October 2008 - 07:03 PM
Matty hit the nail on the head although moot makes a good arguement.
basically the heads cost me nothing, I will be porting them myself, I was mainly just looking for someone to point me in the right direction on how to do the short side on them
whats the going price for a set of VN heads these days?
Better deal would be to sell them...buy some VN heads...and port them...Now we are talking!
R
#23
makka
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Posted 14 October 2008 - 08:46 PM
Porting early heads is an art as i have been told that you need to port them diffrently to any other head to make them work. For some info pickup Street Machine from september this year and read Stage Write, has a little bit of info. I to will be taking to a set shortly, let you know how i go
yep, thats why I was asking because I know that they should be done different to most other heads, I think I have figured out what must be done.
Rory, now thats an idea!
#24
_rorym_
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Posted 14 October 2008 - 09:02 PM
Someone will buy them at big $...Just a thought.
R
R
#25
_greenmachine215_
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Posted 14 October 2008 - 10:49 PM
Like rory said, sell them,
ive also seen complete pairs sell for as little as 250bux.
They do flow 440stock, if you port the short terms on the intakes 9times out of 10 you can gain an extra 100hp more in some cases, only the hardest thing about "backyard" porting, if you don't have a flow bench some ports will flow more than others unless your super experienced,
do a bit of ground work and get some quotes for the intakes to have the shorts evened out, you'll probly find for under 2grand you'll have a fairly cranky top end,
id just like to see you make the right choice and save urself coin in the long run,
Cheers
ive also seen complete pairs sell for as little as 250bux.
They do flow 440stock, if you port the short terms on the intakes 9times out of 10 you can gain an extra 100hp more in some cases, only the hardest thing about "backyard" porting, if you don't have a flow bench some ports will flow more than others unless your super experienced,
do a bit of ground work and get some quotes for the intakes to have the shorts evened out, you'll probly find for under 2grand you'll have a fairly cranky top end,
id just like to see you make the right choice and save urself coin in the long run,
Cheers
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