What is the difference between Ralliart and standard 6G74 heads? How much better do they flow, and will a port and polish improve them, or are they just standard heads with a port and polish job? How much will they increase the compression of a standard three and a halfer? And finally, do they have tougher valve springs to suit the more agressive cams, or are they same as standard?
Thanks,
Aaron.

afaik they are only a different set of cams and hardened valve springs for that cam, the ralliarts compression increase is from the pistons.On that note i was actually speaking to heritage mitsi today about ralliart cam prices and was only 270 per bank and 9.30 each for each hardened valve spring which i thought wasnt too shabby at all.

Im sure someone who has cracked the ralliart motor apart will be along soon enough to give you a exact answer

270 a stick sounds like even I could afford it. I heard that you need a ralliart engine number or there abouts to get these things? So if the ralliart heads don't flow any better I might as well get stuck into the ones I have perched on top af my donk. Cheers.

Like magna00 said, they're identical to the standard heads, just with bigger cams and nitrided springs.

A port and polish will make a difference, although you'd probably need the supporting mods to make any use of it, ie. extractors and high flow filter etc.

TZABOY has modified his fairly extensively, with knife edge porting on the intake, and bigger intake valves.

If you were to deck them (shave the face of the head), it'll increase compression ever so slightly.

yeah i just asked for the tj ralliart cams and valve springs took him a while to find them but he did, if you ring any mitsi place just flog a vin from carpoint to give to them and they will quote you, but i got the quote number from heritage so when i do order them shortly ill get that awesome price

What is the difference between Ralliart and standard 6G74 heads? How much better do they flow, and will a port and polish improve them, or are they just standard heads with a port and polish job? How much will they increase the compression of a standard three and a halfer? And finally, do they have tougher valve springs to suit the more agressive cams, or are they same as standard?
Thanks,
Aaron.

Aaron if you wanna see a comparsion, catch up with me when im back in mannum and i can show you the exact differences between a ralliart head and a stock 3.5 head.

The only difference that we did to the ralliart heads at factory was unshroud the valves by 3mm, nothing else was physically done to the heads, its easier to show you the difference than to try and explain.

The ralliart magna had different pistons in it to get the 9.4 compression and yes the ralliarts ran slightly stiffer valve springs and the cams had 1.1mm more lift than the stock 3.5 cams. They also ran "shorty" style extractors and a remapped ECU to help make the most of the mild mods.

270 a stick sounds like even I could afford it. I heard that you need a ralliart engine number or there abouts to get these things? So if the ralliart heads don't flow any better I might as well get stuck into the ones I have perched on top af my donk. Cheers.

i have a spare set of heads. PM if interested.

Are these Ralliart Heads or normal heads for a porting/flow bench project? Can Ralliart Heads be ordered?

Are these Ralliart Heads or normal heads for a porting/flow bench project? Can Ralliart Heads be ordered?

probably but they will want a craptonne of $$ for them just get a 2nd hand set of heads off a 3.5 get them ported and polished and decked, put a good set of cams or ralliart cams with the nitred valve springs then you have a set thats 100% better then the stock ralliart heads at a fraction of the cost.

Found a old Magazine testing a Ralliart, they recon its got modified cams, cylinder heads modified for more flow and compression is up to 9.4:1, extractors remapped ECU makes 180Kw@5500rpm sounds like a very mild setup.

Found a old Magazine testing a Ralliart, they recon its got modified cams, cylinder heads modified for more flow and compression is up to 9.4:1, extractors remapped ECU makes 180Kw@5500rpm sounds like a very mild setup.

I just stated that 4 posts ago lol

yeah just go aftermarket cams, and up the comp ratio to 10:1, much better

Is there someone in Australia preferably Sydney who can build a flowed Magna Head. It's obviously not just a push rod holden head, and would benifit I think from interest and experience. For more mainstream engines a better flowing head can be bought already developed aftermarket. If there is a better than Ralliart criteria for modifying a Magna head then maybe the criteria ought to be stored and templated. However I don't blame people after their expense for enjoying their secrets!

Sounds like I'm gonna start looking in some wreckers for a set of heads, then spend a bit of cash. Damn apprentice wages. Oh well I don't really mind 2 minute noodles anyway lol
So heads, polished and shaved, with ralliart or stage one cams and nitrided valve springs. Sounds like fun. Do SOHC motors benefit from using adjustable cam gears, or are they just for lazy mechanics who dont like to install the cams properly in the 1st place?

Do SOHC motors benefit from using adjustable cam gears, or are they just for lazy mechanics who dont like to install the cams properly in the 1st place?

Ask Tuffy this.... :P

Sounds like I'm gonna start looking in some wreckers for a set of heads, then spend a bit of cash. Damn apprentice wages. Oh well I don't really mind 2 minute noodles anyway lol
So heads, polished and shaved, with ralliart or stage one cams and nitrided valve springs. Sounds like fun. Do SOHC motors benefit from using adjustable cam gears, or are they just for lazy mechanics who dont like to install the cams properly in the 1st place?

Aaron, got a good complete pair of 3.5L heads sitting in my shed (off my old engine), if ya wanna buy them and tear them apart and have a go at working on them. Also have a set of new valve guides and seats if ya wanted to fitted them.

Catch up with me when im in mannum next and ya can come down and look at them if ya want.

Aaron, got a good complete pair of 3.5L heads sitting in my shed (off my old engine), if ya wanna buy them and tear them apart and have a go at working on them. Also have a set of new valve guides and seats if ya wanted to fitted them.

Catch up with me when im in mannum next and ya can come down and look at them if ya want.

Sounds good! This is starting to get exciting!

Sounds like I'm gonna start looking in some wreckers for a set of heads, then spend a bit of cash. Damn apprentice wages. Oh well I don't really mind 2 minute noodles anyway lol
So heads, polished and shaved, with ralliart or stage one cams and nitrided valve springs. Sounds like fun. Do SOHC motors benefit from using adjustable cam gears, or are they just for lazy mechanics who dont like to install the cams properly in the 1st place?


if you fit adjustable cam gears to a sohc motor and you advance/retard the cam timing, you will most probably negatively affect the other. IE, advance the inlet, and you will retard the exhaust. Best option, if going sohc is to get an upgraded set of camshafts. IIRC the rpw stage 1 cams are just a bit more lift and duration. OK(but not really) for use with the standard ECU.

Standard ECU won't be an issue as I will be fitting a haltech interceptor. Ill also be decking/shaving the heads as well, and Ive heard that any more than 2mm causes interference problems. So 1.5mm should be safe? What effect will that have on the C/R, if at all?

Standard ECU won't be an issue as I will be fitting a haltech interceptor. Ill also be decking/shaving the heads as well, and Ive heard that any more than 2mm causes interference problems. So 1.5mm should be safe? What will that raise the C/R to, if at all?
planning a big NA set up?

planning a big NA set up?

http://workfarce.files.wordpress.com/2007/10/captainobvious.jpg

lol