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ported early heads versus standard vn heads


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#1 _ass308_

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Posted 30 October 2008 - 06:14 AM

My 308 was just stripped down by my engine builder.he was quite impressed with what was already there.standard stroke,30 thou over,yella terra stage 3 heads,roller rockers,edelbrock torker manifold,750 double pumper.
Im stroking it to a 355,and always planed on useing vn heads.I know vn heads are better in the long run,and spent last night going through nearly every page,of the engine forum.
My question is this,CAN an old head be ported to flow as much,as a STANDARD/SLIGHTLY worked vn head.im not asking which is better
Again i know the vn heads are better,and am prepared to spend the money,on them,and the manifold,extractors,and the rest of it.but with my budget the vn heads would only be standard,or slightly worked,at best.I can save myself a shit load of money,by just doing more port work to the old heads,re useing my own gear.The old motor was a beast
i want at least 450hp/400+of torque from the motor.surely pre vn peoples had 308's running around with this much hp.
Any opinions welcomed,i have till saturday arvo to decided,motor to built,by early december,and it will be put on a dyno,before it goes in the car.looking forward to seeing what it can do.

#2 _rookie_

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Posted 30 October 2008 - 05:13 PM

http://www.heads.co.nz/308heads.html

#3 A9X

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Posted 30 October 2008 - 05:42 PM

Short answer.
Yes.
Long answer has been covered here before.

Welby

#4 _ass308_

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Posted 30 October 2008 - 05:53 PM

i saw thoose last night,tempting.what im trying to do is save a bit of money,buy reuseing my old gear.but if it cant be made as good as a standard vn head,then i dont want it.has any1 used them before ?

#5 _lx-304_

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Posted 30 October 2008 - 07:13 PM

im not sure if they still do,but repco have brandnew vn heads for 850.that was 2yrs ago though.i am pretty sure they flow around 500 hp out of the box

#6 _rorym_

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Posted 30 October 2008 - 09:44 PM

Bottom line is yes...with the right person whom KNOWS what they are doing..it can be done...they are at the very upper limit of life/etc etc...so any $$ you spend on trying to get there...against the other stuff you need to bolt on STOCK parts..(remember that bit) is basically covered by the pain/heartache of trying to reinvent the wheel...
The winner for me?..We did a light intake port job...left exhaust standard......and I was bolting on..basically...stock standard VN heads with valves up one size to breath.(I went 2.02 inlets and 1.65 exhaust).....No brainer for me. Flowed 510......Bonus!!
R

Edited by rorym, 30 October 2008 - 09:45 PM.


#7 _HatchmanSS76_

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Posted 31 October 2008 - 06:15 AM

Yes they can but the person doing the work has to know what they are doing to reach stock or slightly worked VN style heads. Not really a home job unless you know exactly what your doing. Can be risky as doing it yourself, you can make them flow worse than what you have now.

#8 _ass308_

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Posted 31 October 2008 - 04:26 PM

after hours of trolling through the forum,and speaking to peeps,ive decided to hang the cost and go the vn heads.u only live once,and i only want to build the car once,so ill do it right 1st time

#9 _rorym_

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Posted 31 October 2008 - 06:17 PM

after hours of trolling through the forum,and speaking to peeps,ive decided to hang the cost and go the vn heads.u only live once,and i only want to build the car once,so ill do it right 1st time


Exactly my line of thinking as well....now...get ready to scare yourself WITLESS!!...with a big grin on your face!
R

#10 _HatchmanSS76_

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Posted 31 October 2008 - 11:56 PM

after hours of trolling through the forum,and speaking to peeps,ive decided to hang the cost and go the vn heads.u only live once,and i only want to build the car once,so ill do it right 1st time



Ah, you are a wise one grasshopper :D

#11 gtrboyy

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Posted 01 November 2008 - 11:22 AM

Good decision to go vn heads,much easier to make 400+ hp with them.

#12 _ass308_

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Posted 01 November 2008 - 01:44 PM

just had a meeting over lunch and a few beers,with my engine builder.narrowed the cam selection down to two cams;
compucam h286
compucam h304
http://www.cranecams...eet_14-5-07.pdf
im leaning towards the 304,the engine builder is leaning towards the 286.any opinions ?.cam and componets will be ordered on monday,so not much time to decide.btw my diff ratio is 3.25 lsd,and im running a turbo 350.
as per usual love to hear your opinion if u wana give it :)

#13 WhiteA9XS

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Posted 01 November 2008 - 03:25 PM

ported early heads 450hp approx

standard vn heads 500hp approx

good luck with the rebuild !

#14 _moot_

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Posted 01 November 2008 - 08:52 PM

standard vn heads are around the 440hp. 500 with a small clean up

#15 _rorym_

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Posted 01 November 2008 - 10:50 PM

^^ Thats what mine did...Why not a 288?
R

#16 _ass308_

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Posted 02 November 2008 - 08:01 AM

a 288 would be to big for me i think(stall to big).im being honest to myself,with what i intend to do with it.its a street car mostly, that i want to be able to fang down the quater every now and again.i also want the motor to be at,no more than 3000rpm at 110kms so i can drive it down the freeway.its not a everyday driver however.
a stroker with a 286 cam rough rev range 2000-5500
a stroker with a 304 cam rough rev range 2500-6000
a stroker with a 288 cam rough rev range 3300-7000
i dont want any more than a 3000 stall,max

#17 _moot_

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Posted 02 November 2008 - 10:08 AM

your cam rev ranges are way out.dont go just off the cam for rpm ranges,carb,manifold,ignition,comp,exhaust and tune all play a huge part.

for instance my old 308 with the 286 made peak power at 6500rpm,and the 355 with the 288 made peak power at 6200rpm.

buy a good convertor.we drive cars around on the street with 5500rpm convertors and there babies to drive and dont slip or get hot. you can still drive around at 2000rpm with a 5000rpm convertor.

#18 _ass308_

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Posted 02 November 2008 - 10:37 AM

moot, basic set up so far 355 stroker,comp at least 10.5.1,vn heads,ported with 2.02 intake,1.6 exhaust,tourque power hi rise dual plane maniflod,750 double pumper,pacemaker 5260 extractors 1 5/8 primaties,into a 2.5 inch collector(maybee upgraded to 3 inch).ignition,unknown atm.what cam would you run,286 or 304?.what ignition would u recomend ?.

#19 _rorym_

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Posted 02 November 2008 - 11:52 AM

Thats my engine with a 288 and MSD..Max power is 6200rpm like moot says...
R

#20 _moot_

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Posted 02 November 2008 - 12:11 PM

get rid of the dual plane,use a tp single, give it 11.5:1 comp (it'll run on 98 fine) use a 288 and 1 3/4" pacemakers and a 950 carb (750 will be ok on a budget) use standard size valves and only just clean up the heads (dont get them hogged out)twin 3" pipes and msd or crane (rev limiter is better on the crane)

a motor with the same specs above made 505hp and ran a 10 in street trim first pass.

#21 _ass308_

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Posted 02 November 2008 - 05:32 PM

moot,im speechless.thats awsome.
im locked in to the 1 5/8 extractors atm.at a later stage ill get the 1 3/4.ill leave the valves standard.i really want to run a hydrolic cam if i can.dont want the hasle of setting valve lash.what size stall did that guy run?.i think thats a little to full on 4 me.ill start with something a bit smaller.i can always at a later stage i can always change cam,manifold carb.
stay tuned,ill see how close i get to the 505 hp.

#22 _mumbo_

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Posted 02 November 2008 - 05:56 PM

And dont forget VN heads just look so mutch better :spoton:

#23 _rorym_

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Posted 02 November 2008 - 07:02 PM

Still think your combo with a 288 will easily get well over 400hp so you are safe with the VNs.
R

#24 _SS Hatchback_

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Posted 08 November 2008 - 07:23 PM

As mentioned before i have early heads with alot of port work and bigger valves and they flowed 450hp so the VN heads are definately better choice, i would have goen with them but when building my engine (10yrs ago) they still wanted big money for them and stroker kits were very expensive :( so im running standard stroke too but everything is cheaper now. Like you said spend the money first time around and in the long run you will save cash. Also what moot was saying is right about stallys , im running a 3200 and it good for the street , think its TCE convertor which i heard were good.




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