2g head in 1g?

[eclipsh]

I've done a lot of reading but most of it talks about why not to put a 1g head in a 2g. I've got a friend with an extra 2g head and intake I could rebuild for my aging 1g. I'm not sure if it is a good move or not.

From what I've read the 2g head flows faster and better than the 1g head due to port angles. Is it worth putting one into a 1g?

If so, what does it take to swap it over besides drlling the head bolt holes and boring out the throttle body opening for my 1g throttle?

As you can guess by my avatar, my goals aren't drag racing. I want fast throttle response and good mid-range torque. I've got the cyclone intake on but not functioning right now, just wired open. Which way should I go?

 

[JWoodley]

This was taken directly from the Magnus website:

"The intake ports have now been made a more normal size. The 1G port was always in our opinion too large to get good low end velocity out of. This head is much more of an improvement over the 1G DSM. The port entry angle is only 10 degrees; whereas the 2G DSM head had a much steeper entry angle, which was better for performance. A lot of manufacturers are getting away from steep angle intake ports which we can only guess for two reasons. A) Low hood line and less complexity for intake manifold castings or B) Emissions. Sharper angles will promote more tumbling and better atomization, aiding in emissions controls."

For low to midrange, I'd recommend a 2G head. For heavy breathing up top, I'd recommend a 1G or ported 2G head. Running a 1G TB on a 2G intake manifold is easy, lots of people have done it. You do need to port match the manifold. Goodluck!

 

[eclipsh]

Thanks, exactly what I needed to know. I guess the only thing left to figure out is if there are special steps to putting the head into a 1g besides those mentioned.

Edit: This thread is helpuful but doesn't quite seem to address everything.

This thread helped me too.

 

[JWoodley]

Just and FYI, you will still use 6 bolt head studs. I'm unsure if there will be any clearance issues, but I think the head diameter on the 1G ARPs is larger than the 2G or vice versa (12mm vs. 11mm) IIRC. Let us know how it works out!

 

[eclipsh]

It's the 1g head that has the larger bolts so the 2g head has to be drilled out.

It'll likely be this winter or next spring before I can rebuild my motor so you'll be waiting for a long time to find out how this goes I just want to get all my plans together well in advance. Another buddy has a 6 bolt block going unused which would make a very handy setup to build a motor and do the swap over a weekend for minimum down time.

 

[blcknspo0ln]

Putting a 2G head on a 1G block:

2g head : 2g intake manifold (ported to 60mm) : 1g TB

2g headstud holes must be bored to 12mm (factory is 11mm), there have been confirmed cases that the 2g headstud holes are large enough, and others have reported that they will bind.

2g thermostat housing : 2g water pipe : 2g lower radiator hose : 2g upper radiator hose\

If you are reusing a 1G CAS, you must wire it in.

If you are using the oem 2g operation, you must put back in a 2g CAS (whether it be on the intake cam or under the intake cam gear) and get the stock crank trigger plate back on with a 2g crank angle sensor. This is more work than needed and I would stick with a 1G CAS.

 

[Batman™]

The 2G head has provisions for a 1G CAS. If this is going into a 1G car, I'd recommend using the 1G CAS. Yes, the head stud holes do need to be bored to 12mm. I'm unsure on the thermostat housings. I don't see why you couldn't just make sure the bolt holes line up and use the 1G apparatus. There's really no difference that I could see other than that the 1G uses the thermostat on the Upper Hose entry and the 2G uses the thermostat on the Lower Hose/Water Pipe entry.

 

[eclipsh]

Thanks guys! That made things nice and simple I'm still debating running the 2g head or my 1g head with the Cyclone intake. It is supposed to give me the better low and mid-range torque that the 2g head does but back when it was working I'd always get knock right when it switched the runners open. Since I'm looking at running MS2 in the car I could probably find a way to tune for that but I'm thinking the 2g head would just be easier to deal with.

 

[blcknspo0ln]

I'll verify when I get home, but unless I'm mistaken, the 2g and 1g thermostat housings have completely different bolt patterns.

 

[Batman™]

I'll verify when I get home, but unless I'm mistaken, the 2g and 1g thermostat housings have completely different bolt patterns.

Thanks. That's the part I'm not sure about, and don't have both here to compare.

 

[blcknspo0ln]

the 2g thermostat housing has a rectangular 4 bolt pattern and the 1g thermostat housing has a triangle 3 bolt pattern.

so, you gotta use a 2g thermostat housing / water pipe / lower radiator hose. ;P

 

[eclipsh]

Good to know, thanks!

 

[Xit40]

I have a 1G thermostat housing on my 2G head. It's really up to you which one you want to use. When I put my 6 bolt in my 2G Magnus' site says to use the 1G housing with the 1G water pipe (I prefer the 90 pipes, no water cooled oil ) so I did.

 

[tkelly27]

FWIW, I ran a 2G style head with a 1G intake. The runners did not match at all. It's not the most efficient setup, but it ran perfectly.

 

[blcknspo0ln]

I have a 1G thermostat housing on my 2G head. It's really up to you which one you want to use. When I put my 6 bolt in my 2G Magnus' site says to use the 1G housing with the 1G water pipe (I prefer the 90 pipes, no water cooled oil ) so I did.

Curious as to how you bolted it on. Seeing how the bolt patterns differ?