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Discussion Starter · #1 ·
I have a '73 GT and I'm getting all the information i can to completly restore it. so bare with me i have a few questions that i cant exactly answer for myself consedering my cars 800 miles away from me waiting for me to get home from college this summer.

I have decided to replace the 1.9 thats is in it right now with a 2.2 from opel gt source i will also be replacing the original tranny and clutch with at getrag 5 speed and a 9" clutch and flywheel. I'm also going to replace all the brakes with new disc brakes. ok questions

1) am i going to need to beef up the rear end any from the stock rear axle and differential.

2) what would be the best brake upegrade for that drivtrain setup (money is not an issue i plan i spending the money that i would spend on a new vehicle to make this a sweet daily driver)

3) and since I'm adding bigger brakes what would the dimentions for my wheels be such as centerbore appropriate offset i will also be droping the car by about 1and a half so in that case should i use a 15" wheels with a 10 or 20 series tire or could i fit 16's with a 10 series.

4) has anyone had any problems with anything that i have asked about.

thank you all so much for reading this and for any help you can provide. I love my opel and can't wait to get it out on the road again.
 

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Where to start,

You need to do some grinding on the getrag bellhousing to fit the bigger clutch.

Where are you getting the disc brakes?


Rear end will handle up to 150 hp depending on how you drive it.

You can probably do the 15 inch rims but when you lower the car it is really stiff. Keep that in mind when you start loosing sidewall.

Lastly, where in Colorado are you?
 

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Discussion Starter · #3 ·
well i dont know for sure where i was going to get the breaks i was hopeing some one could help me with that and im from the San Luis Valley in colorado which is like south central i was thinking about doing this car with kind of a super street attitude but keep the grace and lines of the GT
 

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There are Isuzu brakes that will fit. Do a search and you will see quite a bit. Also OGTS sells a package. I have seen some on Ebay also. There is a setup from an Isuzu looking for a home somewhere in Colorado. South central would be Pueblo or Canon area or further south.
 

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Discussion Starter · #5 ·
well about 2 hours south of pueblo its closer to new mexico does everything swap directly over from the isuzu or do you need to modify rear end and were was that isuzu setup
 

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From what I saw of the package it did need new backing plates for the axles. I don't know about a direct bolt up except for the one OGTS sells. The last I heard the owner of the kit was on his way to see Doc in Denver. I'm sure it will surface soon. From what I have seen there are at least 4 GT's around you, or at least within a short drive. 2 drivers 1 in storage and mine.
 

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Discussion Starter · #7 ·
were are you located at anywhere near pueblo or walsenberg trinidad? it be nice to know someone if i had a extreme problem that was nearby
 

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Yes I am that close, not sure but it could be a local call. I go up and down the front range all the time. I am at the new school being built in walsenberg every week. I shy away from spending time in Trinidad. I can't tell who is there recovering from surgery, if you know what I mean.

Alot of the things you have talked about I have done to mine. I went a different route for more power and my brakes are still stock. Just let me know if I can help you.
 

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Discussion Starter · #9 ·
right on yeah i know what you mean about those trinidad people anyway thanks I've talked to at least a dozen mecanics and none of them will even work on it let alone help fix it in any way and the GT engines just not the same as your conventional engine so its a struggle sometimes working on it I know i've done things the hard way more than once. anyway thanks again and i'll look you up if i need some help
 

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What color is your car maybe I know it. Is it a Colorado car?
 

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Discs Looking for a Home

The wandering, homeless Isuzu Impulse rear disc set was put together here in New Zealand and posted over there to Colorado in exchange for a box of real good GT parts!

If you see the GT driver who has them say "Gidday" from me as he is "off-line" on an extended road trip - so I am told!
Have not heard from him for about six weeks.

I am working on using the "turbo" Isuzu front discs for my 1972 GT but though the discs and hub have the same bearings as the GT and fit on the spindle the Isuzu calipers are a bit harder to adapt. Presently trying to fit the entire Isuzu spindle into the GT front suspension - it's close but geometry still needs to be checked.

Have settled on using the entire Impulse diff at the back but needed relocation of the spring cups and the panhard rod is attached on the opposite side so the original GT ones need to be put on to the Impulse diff or some such modification.
Probably easier to fit the bits to a GT housing.

Get 3.9:1 gears, a limited slip unit AND rear discs with the Impulse stuff but it is a bit of work.
 

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Discussion Starter · #12 ·
its white with blue spray paint or something from the previous owners above the wheel wells but its actually under a cover right now. im in Idaho at the moment going to college so i dont reallly trust anyone to drive it
 

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I'm doing the same

I too am rebuilding a daily driver. I sold a perfectly awesome sportscar to finance this endeavor. Some people think I am crazy, but I have been an Opel fan since I was a kid, but never had the money to do one right. I had one in high school, but didn't have money then. So I am trying to do it right this time.

I am about half way done with all of the upgrades you mentioned. I used Opel GT Source (OGTS) http://www.opelgtsource.com to purchase most of my parts.

I don't have the tools, space, or time (or knowledge) to do more than the basic work. It took a lot of checking, but I did find a shop that had been working on Opel GT's over the years and they were happy to help me with the big stuff.

Instead of the 2.2 opel engine, I decided to go with the 2.4L. While I was waiting to get a rebuilt one (trying to avoid paying for a possible rebuild) the guys at OGTS found an Irmscher i240 version of the 2.4. Irmscher is an Opel tuner that produced higher performance versions. I decided to risk the possible rebuild to get a special engine.

The engine came with fuel injection, so I am going that route instead of some of the different carburator setups you can do. It does require a fuel pump and extra fuel line to return to the fuel tank.

The engine I got had a crack in the exhaust manifold, so I decided to replace it with headers. I was able to find them at http://www.opelsunl.com I am having them heat coated locally.

I went with the cheaper big brake package from OGTS. It did not fit as well as they said and I ended up take more than a quarter inch of the wheel hub to get it to fit. I also have ordered a wheel spacer from http://www.metalaction.ca to get room for the wheel to fit next to the caliper.

I simply replace the rear drum brakes assuming the the upgrade to the front disc brakes will be sufficient. I could not justify spending $2k for a rear disc kit. I don't want to put salvaged parts on either.

As far as wheels go I went with Ronal's 15" 7.5"wide LS. http://www.ronalusa.com I went with the 12mm offset, however I might wish I had the 20mm offset after I put the wheel spacer on. I ordered some Kumho 205/50 and that combination was a huge improvement in handling.

I cannot wait to see how the new intermediately lower front leaf spring, bushing, shocks, and front/rear sway bars help!
 
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