buick 231 90 degree V-6 in a '72 GT

[blancojp]

Howdy all!
GT Jim had a few questions on one of my cars and I hope this answers the big question, does a 3.8L engine fit in an Opel GT? Yes it does and quite well.

It does not require lots of cutting, the car handles the same as before with all new stock components, the rear end has worked fine for 6 years and you can even use the stock hood locking mechanism, if you plan it properly. Here are a few pictures to show the fit in the engine compartment.

Also note my newest upgrade, a 1996 Honda 22mm master cylinder mounted onto the stock brake booster. Just $20, drill two holes and get a substantial brake difference.

[hustlerzlife]

How much money can you ballpark the conversion to cost and about how many hours did it take you or someone less experience?

[Mike Trout]

All you need is a Turbo setup out of a Buick grand national then you may be able to pass a few hondas
hehehe
Mike,
happy opeling
p.s. very nice

[blancojp]

I took almost three weeks for all the work to be done but we were doing it in our spare time during the day. The engine took 10 hours to install but I had several people working on it. I had a metal guy, a welder and myself working on the car. I did help us alot to have a mock up plastic engine and tranny to work with but I would not recommend anyone without basic experience to do this kind of work. Once we had all of the metal work and chassis reinforcement done, we installed the engine and tranny and sorted all other items out. I drove the car a few weeks before we decided to restore the vehicle completely which took two months. Money wise, we did the conversion for about $900 originally then when we restored the car, close to $25K went into it since everything was new or rebuilt.

In a nut shell, the V-6 with 305HP just makes the car fly, when you accelerate the car lifts evenly front and back. It tracks evenly and flat on corners and does nose dive a bit when I brake.

Any classic car requires time, tools, work and money.

[GTJIM]

That looks a nice, neat installation - the front mounted distributor certainly makes life easier than the rear one on a 60 degree V6.
The tip on the Honda Master cylinder is good too.
Here, the late Holdens RWD come equipped with the all alloy 3.8 Buick 90 degree V6 and TH700-4R autos - there is even a supercharged model.
Now, where can I find a parked one ??

[SpringGT]

JB,
Again, nice job on the engine swap! Do you have any photos that you could share of the underside showing the transmission fit, exhaust system, frame reinforcement, motor mounts, etc.
Also, for those of us in hot climates, is there room for a small Sanden AC compressor under that alternator? Thanks for the M.C. tip too.
Bob

[blancojp]

I did not plan for an A/C unit on this car but I do have another '73 with a chevy S-10 engine and T-5 tranny that does have A/C. I bought an A/C system that has everything inside a 20x14x8 box which goes mounted on the package tray.

I'm updating the brakes (again!!) since I saw a few things I liked at the junk yard which I believe would be great on the Opel. That is where I saw the master cylinder, took a few measurements and saw that it would work. It fits like a glove when you turn the fluid tank around and you only have to drill the mounting holes inward but the rest is the same as the Opel. You will also need a "tee" for the front brakes but that I have plenty off. BTW the "tee" is part #BQ91 from brakequip and they are about $5.00 each.

Here is the pic on the master cylinder

[soybean]

Very, very nice job. Why not do a write up on the brake master cylinder(s)? Those little buggers are getting hard to find now day, and as time goes on, people will need to upgrade. Once again that is a sweet looking conversion. Thanks, Jarrell

[BQS4]

What model '96 Honda was the M/C from?

[blancojp]

The master cylinder is from a 1996 Hoda Civic with ABS brakes. I bought the master cylinder new on Ebay for $10.00 which is hard to beat. The fluid tank can be reversed by removing the lower attachment screw. The way I did it was to install the master cylinder to the brake booster and then put in the fluid tank and securing screw. You will need a "tee" for the front brakes but other than that, it is a good and simple replacement with better performance than the original. And it restores brake pedal firmness with the Volvo caliper setup.

I have a complete brake upgrade guide I'm working on with substantial front and rear brake options. This guide will have full detailed step by step instructions on how to upgrade your front and rear brakes.

[hustlerzlife]

Once we had all of the metal work and chassis reinforcement done, we installed the engine and tranny and sorted all other items out.

What did you do to reinforce the chasis and what or how much did you cut? Does the tranny fit very good? Which did you use? Thanks for all the information my mouth is watering and its not just the candy I'm eating right now.

[blancojp]

The front U-channel on both sides was opened up at the welds and a 1/4" flat bar was spot welded inside. Once done, the sheelmetal that covers the channel was welded back in place. The transmision fits like a glove and I even used the stock Buick crossmember without any modification.

The driver's side was modified by removing 2" all accross the top and bottom. the steering was angled differently using two flex joints and I used a Lokar spoon type accelerator pedal.

Here are some additional pics of the car.

[StephenM]

Looks like a very clean install, great work!

Out of curiosity, what seats are those? They look real nice and are apparently narrow enough to fit, which is no mean feat.

-Stephen M

[blancojp]

Thanks to all for your compliments on my vehicle. Believe me, it runs lots better than it looks.

The seats are from a Scion XA with redrilled universal sliders. These were covered in black leather before they were installed with a 4-point harness. What no one has seen are the 11" front vented brakes which I am including pics on this post.

[daveegt]

The front U-channel on both sides was opened up at the welds and a 1/4" flat bar was spot welded inside. Once done, the sheelmetal that covers the channel was welded back in place. The transmision fits like a glove and I even used the stock Buick crossmember without any modification.

The driver's side was modified by removing 2" all accross the top and bottom. the steering was angled differently using two flex joints and I used a Lokar spoon type accelerator pedal.

Here are some additional pics of the car.

I ran across your message saying you put a 1996 Honda master cylinder on your GT. Can you tell me just what you had to do? I bought a GT that need new brakes. Can you help??
Dave

[blancojp]

The only mods to the master cylinder is the mounting holes, you have to drill them closer to the pump stem. Then is a matter of just installing the master on the booster, installing the reservoir, adding a "tee" for the front brakes, bleed and you are done. We do sell a kit that has all parts and is ready to bolt and go for less than a rebuilt Opel unit.

The Honda master cylinder has approx. 6mm of additional piston travel so this compensates for the additional compliance required by bigger brakes. With the stock booster, I have seen pressure as high as 700 psi comming from both ports with very minor pedal travel. You can't bench bleed due to the fact that you have to remove the reservoir to install the master cylinder on the booster. For stock applications use the 13/16" unit which performs lots better than stock unit. If you have rear disks or Volvo front calipers, the use the 7/8" unit and it will stop your car with minor effort.

We are doing a '71 GT with 4-wheel vented disks retaining the 13" wheels for one of our customers. This car will have a 9" Girling booster with chevy front rotors and floating calipers, Honda rear rotors and El dorado rear calipers with E-brake. This combo is so sweet it should be illegal.

[BQS4]

We are doing a '71 GT with 4-wheel vented disks retaining the 13" wheels for one of our customers. This car will have a 9" Girling booster with chevy front rotors and floating calipers, Honda rear rotors and El dorado rear calipers with E-brake. This combo is so sweet it should be illegal.

Please keep up with updates on this venture as some of us are looking at this same idea.

[azopelnut]

Howdy all!
does a 3.8L engine fit in an Opel GT? Yes it does and quite well.

It does not require lots of cutting, the car handles the same as before with all new stock components, the rear end has worked fine for 6 years and you can even use the stock hood locking mechanism, if you plan it properly.

Wow....
This sounds great but isn't the 3.8 a lot heavier than the 1.9?
With all the interest in swaps have you ever thought of taking your modifications and create a kit with how-to instructions! I really admire your ability to adapt other make components into our Opels. Ron DeLosiers 3.4 GTwas a gas. The 3.8 would have to be a real kick too!

[bigben]

I've got a quick question before I go running out to the nearest auto parts store to buy a Honda master cylinder. When a Opel master cylinder starts to go bad, how does it behave? I've done a good job bleeding all four brakes a couple of times and the calipers aren't stuck but whenever I first step on the brakes the car pulls to the left before equalizing. Any ideas?

[blancojp]

The 3.8L is not as heavy as people think, it is only 58lbs more than a 1.9 in stock form. All my suspension is stock and the car handles as good or better than with a 1.9L. With the V-6, 0-60 is no longer a concern since with my newly redone th350 I get there in less than 4 seconds. Traction is a problem but we are working on a replacement for the Opel rear unit which is not expensive.

There are lots of Jap parts which are direct fit or require minor mods to make them work. That is why I proposed to start a thread called "riceing your Opel" since the amount of usable available cheap parts are out of this world.

And yes we do have kits for different engines, trannny, brakes, steering and other items for different cars. These are items we have developed over a 20 year span and pricing is somewhat reasonable.