304 head work

[gelousi]

Hey guys, whos good for head work with 304's? as in port polish etc. Im thinking of doing that and getting them machined as much as possible to raise comp. do many people do this sorta stuff to there 8s? or is it not worth it?

cheers

 

[vyjess]

unless u have a big cam and chasing big hp its probly a waiste of money. if its a standard motor with a baby cam just a good valve job and get them machined is all that is needed as 304 heads flow heaps anyway.

 

[GenReaper]

Shaving the heads for some extra compression does help and produces more Torque and HP.
Wouldnt bother polishing them, waste of money.
Slight porting can help but $$$ for the ammount of performance isnt viable, they aint bad stock.

IMO Shave the heads for around 11.2-1 compression and good 3 angle valve job some new gaskets is about as far as you would want to go unless you want to crank it right up.

 

[padrickz88]

Shaving the heads for some extra compression does help and produces more Torque and HP.
Wouldnt bother polishing them, waste of money.
Slight porting can help but $$$ for the ammount of performance isnt viable, they aint bad stock.

IMO Shave the heads for around 11.2-1 compression and good 3 angle valve job some new gaskets is about as far as you would want to go unless you want to crank it right up.

ummmmm CR of 11.2 just by shaving heads? LOL goodluck

 

[GenReaper]

ummmmm CR of 11.2 just by shaving heads? LOL goodluck

Maybe, im not sure how far those heads will go.

Only other option is to deck the block some.

Either way it will net more usefull gains than leaving them standard.

 

[vk5ltr]

max cr you ll get is about 9:8:1 or something like that with an 80 thou head shave then the manifold has to be machined to fit i shaved mine 25 thou for around a 9:2:1 cr but i am yet to know if my current motor has flat tops or not as it makes good power for a carbd 308

 

[greenfoam]

You wont see gains with head work on the VN heads until the motor is making fairly big power, ie nothing with a banana manifold is going to gain more than a few hp. Also with a standard cam or a mild cam even 10:1 compression is about the limit before you start to cost yourself power due to pinging and not being able to get the potential power from the motor. To run 11:1 and above you need a much larger cam

 

[gelousi]

hmmm ok then gets me thinking, Well im going to go to duggan's balancing in reservoir and ask him for some advice i heard he is pritty good with his 8's. I contacted crow cams and gave them the part number of the memcal to tell me what motor it is for, the motor that's in the car is a vs senator 185i but the memcal from what im thinking is for a vr 165i. is that possible would the car still run perfect without me noticing anything? I had trouble setting base timing then i added the knock board as it already had the sensor now the base timing can be set but when i start the car the maf doesn't suck air and it dies out i need to hold the revs up for about 5 secs to get it to idle.

 

[savage1987]

hmmm ok then gets me thinking, Well im going to go to duggan's balancing in reservoir and ask him for some advice i heard he is pritty good with his 8's. I contacted crow cams and gave them the part number of the memcal to tell me what motor it is for, the motor that's in the car is a vs senator 185i but the memcal from what im thinking is for a vr 165i. is that possible would the car still run perfect without me noticing anything? I had trouble setting base timing then i added the knock board as it already had the sensor now the base timing can be set but when i start the car the maf doesn't suck air and it dies out i need to hold the revs up for about 5 secs to get it to idle.

The 185i and 165i are the same motor. The only (slight) differences are intake exhaust and tune, if that helps at all

Sam

 

[psytops]

u dont have to shave the manifold u can shave some off the inlet side if u can work out how much Johny Dynos in geelong pulled my heads down i got them shaved else were they put them back together and went 50 off heads and 30 of the inlet 366 with out the port work