Dream G-Body

[dougfather]

Ok...let's pretend for a moment that in 1978, GM decided to have only one brand of car. Therefore, the G-Body line was only one model. How would you build it?

Rules

Body/Interior-anything G-Body 78-87 is fair game. Even the oddity G-Bodies.

Engine/Transmission - anything available from GM in 78-87 is fair game, so long as it was available in other passenger cars (not just trucks, like a 454 V8). Engines can change from year to year (ie, allow for 4.3L V6 TPI in mid 80s). ONLY 3 ENGINES CHOICE FOR ONE MODEL YEAR ALLOWED!!


My G-Body
Interior - Grand Prix. Very few changes were ever made, so it would be the same throughout, aside from wiper switch and larger radio (85-up)

Exterior - 81-87 Cutlass w/ the euro front end. The 4 door model and wagon model would be offer up to 87, both being Olds.

Engine Line Up
78-83
229 Chevy V6-2bbl
305 Chevy V8-4bbl
350 Chevy V8-4bbl

84-87
4.3L Chevy V6 TBI
305 Chevy V8-TBI
350 Chevy V8-TPI

Transmission
78-83
T-5 (std)
THM-350

Transmission
84-87
T-5 (std)
THM-200-4R (opt)
THM350 would be phased out.

In effort to maximize economies of scale, I would stick with on family of engines (what GM should have done). All motor mounts are the same and pistons could be shared from V6 and V8. Using EFI setup on all models from 84 on would commonize to one fuel sending unit.
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[mcsslover1987]

Ok I guess I'll have to go with the 87 Olds Cutlass 350 TPI/5 speed (Hurst Olds or 442 prefered). Cool subject!!

 

[Derision]

Phroo... that's a good one.

I agree with most of that, except that I would also through the turbo 3.8L in there, as well.

Also, I would give it the stance that they gave the 1982 model year Grand Prix, with the rear-end jacked up about two inches.

 

[85 Cutlass Brougham]

I would have spent more time on interior ergonomics than GM did. The other thing I would have done would be to work on improving combustion efficiency to cut emissions rather than hobble the engines with stop-gap measures. Things like heart-shaped combustion chambers-first seen on Vortec heads- were known at the time as they were first used in a production engine in the 1950's (BMC A series, used in the Mini, Morris Minor, etc). I would cut dressed engine weight with more efficient accessory drives and better materials usage like Ford did in 1978 with the Fairmount. For engine choices, I would go with 2 Chevy V8's but only use a 350 with it's original bore and stroke. They would both use the Quadrajet carb and HEI, but I think the 305's bore size makes it inefficient and a 327 would be a better mid range engine, maybe with a longer stroke and slightly less bore to improve NOX emissions and flame front propogation. My third engine choice is a diesel but a different design, maybe a 5 or 6 cyl turbo diesel with floating liners like a big rig or Mercedes OM617. I would spec it as an inline as it would have less of a tendency to tear itself apart down the middle since forces would be more equalized. I would also put the gas tank below the back seat and put the spare tire in a well below the trunk floor to improve: rear impact collision survivability, cargo space and weight distribution. I would push the front wheels about 6-10 inches farther forward to improve front-rear weight balance like Mercedes and BMW did at this time. This would cost nothing extra but improve handling because the front axle centerline is placed in front of the engine and ride quality since the longer wheelbase would dampen bumps better.( look at newer RWD cars and you will see that the space from the door to the wheelwell is longer than on older domestic models). This is commonly called a "Front-Midship" design and is common on good handling cars. GM did it starting in 1963 with the Corvette, which had perfect 50/50 weight distribution. I would also run an aluminum steering box like GM did on the Vega to further cut frontal weight, or switch to rack and pinion like GM provided to AMC for the Pacer. The aluminum hood and core support would be standard instead of just on a limited number of cars. For transmission choices, the T-5 and TH200 4R are the best choices for later cars and the TH350 and a Saginaw 4 speed for the early ones. The 8.5 would be the only rear axle, just like it was for the 75-79 X bodies. Wheels would be 15x7 with a 235 60 15 tire size.

Another thing that could have been done is an improvement of front suspension geometry. This would have allowed for better handling without the use of very stiff springs because the tendency would be for the front wheels to keep a wider contact patch rather than go into positive camber gain with compression. If done from the factory, the "tall spindle" setup could have been done without the bump steer you supposedly get with B body spindles since you could keep the arc of the tie rod in the same plane as the arc of the lower control arm.

 

[Vern]

85 Cut Bro, You always have a lot of informative thought out responses. Interesting when I got into the 68 to 76 Cadillac 472/500 I was surprised to learn that not only was the engine castings / materials / components / machineing / "standard of the world" for its time but the design of the combustion chambers etc such as you were refering to were ahead of the curve. They have modern heart shape combustion chambers like GM now uses on the LS1 & LS2 series heads & even have the same fireing order. A decked honest 10-1 static 76cc headed 472/500 runs well on 89 octane even when pushed in hot humid weather assuming the rest of the cooling system is up to snuff.

 

[85 Cutlass Brougham]

That's both cool and infuriating at the same time! If they really knew all of that at GM back in the 70's why did they not incorporate it into all of their engines and keep reasonable compression ratios instead? I would ask the same question of every domestic manufacturer who had 8.5 or even (Yikes!) 7.8:1 compression ratio engines in the 70's? I mean, if you look at the different trade-offs you can make when designing or spec'ing out an engine it makes no sense at all. It would simply involve tooling up a new casting for the heads which would then allow more compression and in turn that would allow more cam timing and lift. Instead, they dropped the compression ratio which increases NOX emissions because of excessive free space and insufficient quench. (It also helps with CO2 and HC emissions which is what they were crutching their engines to do, but they could have done both with improvements in efficiency.) Then in turn they made the cam smaller to help keep the low RPM cylinder pressure up in order to keep the idle quality good. This is basic engine theory 101 but no one back then seemed to realize just what was possible with the technologies already available to them. It leads me to believe that it may have been GM's corporate structure that kept this from happening.

 

[Tony_SS]

Any G-body with a Jeff Swartz rolling chassis and an LS7! 8)

 

[Silent viewer]

84-87 GN body and dash, spoiler, hood, rear end, 442 buckets, 350tpi, i am not sure if i would go for a 5 speed or a GN 200r4......., chrome iroc(they were available) wheels, t tops.... basiacally a 87 GN except with 442 seats and a 350 tpi motor(i know the turbo 3.8 is awesome but i LOVE the sound of a v8) oh and one thing NONE of them had, REAR DISCS! i hate drums! crazyiest part is that it was all available and gm didnt do it!

 

[83cut350chev]

my ultimate gbody would have an 81-86 cutlass front end,grand prix dash,442 buckets,regal tailights,442 rear 3.73s,350 TPI w/T5 i like the idea of rear discs too, and t-tops of course