1g Head on a 2g 7bolt

blanks · Aug 15, 2013

Ok so I have a 6 bolt head on my 7 bolt 97 4g63 engine. I am wondering if there were many differences between the heads? I know the lifters are different (thats how I spotted that the head is off a 6 bolt), im going to be ordering some new exhaust valves aswell as ARP headbolts soon and am wondering if there is a difference in the length? aswell if theres any other advantages or disadvantages to having this setup. Any input is welcome.
Thanks
Edit - I was just thinking, wondering I bought this car only about 5 months ago and decided to do a complete engine/partial tranny rebuild. I have no idea whats original and what isnt, although I know its a 7-bolt, but it could have had a whole engine swap and possibly have the 1g 7bolt? is there anyway to tell the difference? the main bearings and crank are held by the 2nd gen cradle, and the head has the two bigger studs for the intake manifold, I was just reading you can have boost problems if the intake manifold is a 2nd gen on a 1st gen head. Ill have to look and see if the intake manifold is 1st or 2nd gen. not sure what the differences are though.

mitsdsm · Aug 15, 2013

The intake ports are different and they have different size head bolt holes 12mm vs 11mm. As for what one is better I would say this people have and do make big power with both heads. The valves, springs all that suff is the same.

Will I am building a 2.3 with a 1g n/t 7 bolt and it has a 1g head and intake also has crank cradle so you could have 1g 7 bolt. Also mine does not have oil squiters.

blanks · Aug 15, 2013

so from what I recall the 11mm are on the 7 bolts an the 12mm are on the 6 bolts? So what am I gonna be able to do here, can I use the 12mm for the 6bolt head 7 block block? or do I have the use the 11mm?

spyderdrifter · Aug 15, 2013

You'd be better off getting a 2g head for it. The 2g head does flow air better. That's if you plan to build up the engine.

spyderdrifter · Aug 15, 2013

Since the OP has a 2G block, the holes being drilled out for a 6 bolt wouldn't be beneficial.

blanks · Aug 16, 2013

yeah im looking for a 2g head to fit a 2g block, now im wondering this had stock head bolts in it, and from what i could tell they fit just fine, what issue am i gonna run into if i try an put the 11mm arp's in?

BogusSVO · Aug 16, 2013

With the 7 bolt block and 1g/6 bolt head, you will need the 11mm head studs, ARP 207-4203.

Valves, springs, HLAs are all the same 6 bolt/1g and 7bolt/2g

Nothing needs to be done to the head for it to bolt up to the block.

Make sure you use the large runner intake.

Check the Marketplace tab, and the supporting vendors, they should be able to get you the head you need if you want to go to the small runner 2g

gsxeclipse97 · Aug 16, 2013

I agree you'd be better off with a 2g head. I ran that setup for a long time and I'm much happier now with the 2g head back on. I also used a cyclone itm actuated by and rpm's switch. And even with that I still prefer the 2g with evo3 itm. I still have the cyclone manifold if your interested. It will allow you to keep your low end without sacrificing your 1g head benefits.

LandSpeed-DSM · Aug 16, 2013

spyderdrifter said:
You'd be better off getting a 2g head for it. The 2g head does flow air better. That's if you plan to build up the engine.

First: Define your criteria for "better."

Second: Data or GTFO :thumb:

BogusSVO · Aug 16, 2013

LandSpeed-DSM said:
First: Define your criteria for "better."

Second: Data or GTFO

Land speed, we may bump heads here..., My personal thoughts are the 2g/7 bolt head will have a slight advantage in off boost drivablity and flow under 7000 rpm

Now once you get up over 7000 rpm, And swallowing huge amounts of air then I can see an advantage going to the 1g/6 bolt head, just for the shear mass it can take.

Now for some data...

http://www.dsmtuners.com/forums/art...1g-head-flow-numbers-intake-designs-long.html

I can not confirm or deny this info. I have not taken the time to set up on my flow bench.

Archer Fabrications · Aug 16, 2013

Bogus, how about if you port the 2g head.

LandSpeed-DSM · Aug 16, 2013

BogusSVO said:
Land speed, we may bump heads here..., My personal thoughts are the 2g/7 bolt head will have a slight advantage in off boost drivablity and flow under 7000 rpm

Now once you get up over 7000 rpm, And swallowing huge amounts of air then I can see an advantage going to the 1g/6 bolt head, just for the shear mass it can take.

Now for some data...

http://www.dsmtuners.com/forums/art...1g-head-flow-numbers-intake-designs-long.html

I can not confirm or deny this info. I have not taken the time to set up on my flow bench.

I think we may agree on quite a bit in this regard, more to the point I want to see that position (as a blanket, unsubstantiated statement) defended and explained by the poster.

LOL

The previous head that was on my engine (1G head) was a hand-ported job I put about 50 hours of work into and moved near-as-makes-no-difference 330cfm @ .450" under 28" vacuum with no intake on it. Damn shame we found signs of cams binding when we took it apart to install the new kiggly valvetrain.

Tried to run a mandrel through the cam journals and trim the caps, but the head was trash. Slight diagonal warp, from intake/passenger side to exhaust/driver side.

Can't tell you how disappointed I was when the machine shop shared that bit of news with me. Car currently has a stock unmolested 1G head on it.

BogusSVO · Aug 16, 2013

urbansmoker1 said:
Bogus, how about if you port the 2g head.

Proper porting will help either head. But there is just not the volume of space in the 2g/7bolt head, even ported, that is in the 1g/6bolt intake runner.

There is 2 basic schools of thought, one is velocity, the other is mass.

Velocity is more important on a NA and off boost driving. (DD, Street strip, auto X)

Mass is more for upper end, and screw the off boost driving (Dyno queen, trailered Drag, LSR)

LandSpeed-DSM said:
I think we may agree on quite a bit in this regard, more to the point I want to see that position (as a blanket, unsubstantiated statement) defended and explained by the poster.

Ok gotcha!! :thumb:

spyderdrifter · Aug 16, 2013

LandSpeed-DSM said:
First: Define your criteria for "better."

Second: Data or GTFO

My data came from the "search" feature of this forum. Read it all back when I was curious to this since I have a 6 bolt head sitting in the garage. Not gonna post all the data since I went through searching. I'm sure this won't please/satisfy you, but it is what it is. Everyone's views and opinions are different, so I'll leave it at that.

http://www.dsmtuners.com/forums/search.php?searchid=13240955

http://www.dsmtuners.com/forums/new...ow-comparison-via-power-difference-1g-2g.html

And I know there are other write ups since I couldn't find what I had read in the past.....

LandSpeed-DSM · Aug 16, 2013

"Better" is subjective considering they have different strengths and weaknesses, was the point I was making.

spyderdrifter · Aug 16, 2013

Yes, I agree, they both differ with what you just mentioned. It just always seems to be the 2g head out performs the 1g head. I'm not here to step on anyone's toes. Just offering my views. Maybe "better' wasn't the best term to use.

iceman510 · Aug 16, 2013

spyderdrifter said:
Everyone's views and opinions are different, so I'll leave it at that.

It should not be based on merely "views and opinions". That is why he asked you for a definition. The specific goals and usage determine which would be better for any given setup. Bogus explained it well.

Not attacking here at all either, just that as mentioned, a blanket such and such is better statement is not definitive.

LandSpeed-DSM · Aug 16, 2013

spyderdrifter said:
Yes, I agree, they both differ with what you just mentioned. It just always seems to be the 2g head out performs the 1g head. I'm not here to step on anyone's toes. Just offering my views. Maybe "better' wasn't the best term to use.

Neither is "seems" ... I realize that seems like pedantry or being a dick, but this is how misinformation is proliferated.

Archer Fabrications · Aug 16, 2013

LandSpeed-DSM said:
proliferated.

Thats a big word

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