Engine Swaps? What's the real story?

[joe_padavano]

455s just have way too much torque and will eventully twist the frame,especially if its a modified 455.

Where did you hear this??? I've had a 455 for years and never twisted the frame. There's no such thing as "too much torque". 😉

Clearly, this must be why people swap Chebby motors into their Cutlii... the Olds will destroy the car. 😀
(It's a JOKE people)

 

[3XBrownCutty]

Clearly, this must be why people swap Chebby motors into their Cutlii... the Olds will destroy the car.

Dammit!!I knew there was a kicker!

If you were feeling real gutsy you could grind off the casting #'s on a 350 or 403 and find a way to re-create the numbers and match all the castings on the 307. It would be very time consuming though..

 

[joe_padavano]

If you were feeling real gutsy you could grind off the casting #'s on a 350 or 403 and find a way to re-create the numbers and match all the castings on the 307. It would be very time consuming though..

Chris Witt has figured out how to do this when he converts normal 69 intake manifolds to Hurst/Olds manifolds. I asked and he will not share his secret, however. I'm guessing it's a silicone mold with some high temp epoxy.

 

[3XBrownCutty]

Chris Witt has figured out how to do this when he converts normal 69 intake manifolds to Hurst/Olds manifolds. I asked and he will not share his secret, however. I'm guessing it's a silicone mold with some high temp epoxy.

Definitely possible.

But if that info. made its way into the wrong hands, someone could possibly make a huge profit off of a set of (for example) #8 heads by changing the casting to a 5 or 6.

 

[dogsht]

One reason many of us like the gbodys is that they were the last of the full framed cars much like a truck. A very strong platform with which you can build on. With factory braces and X braces across the trunk my Cuttys never twisted with a 509ci between the framerails that made about 570TQ. It also had stuff to help provide traction. For Cali emitions I would do a well built but relatively mildly cammed 403. Maybe someone can list some of the Olds vendor builder gurus around the country.

 

[svltrack]

Depends on the wording of the law but I highly doubt that a law controlling emissions would have anything to say about engine displacement(at least not in such clear terms)

If I were running an emissions test on your car here in PA I would go over it visually first to see if the factory installed items were in place. If the OE equipment was in place I would then plug it in and run the test. The machine does the rest.. at least it used to about 7 years ago the last time I did one of these. I am not looking at blocks or vin #'s. Just that it passes with the correct equipment and by the gas analyzer. That is the end of it. To most mechanics doing emissions test are a big waist of time and do not pay. They want it done and out of their bay

 

[joe_padavano]

Depends on the wording of the law but I highly doubt that a law controlling emissions would have anything to say about engine displacement(at least not in such clear terms)

Actually, the law requires that the configuration of engine size, cam profile, valve size, etc, etc, be certified under the EPA with the factory installed emissions equipment for the standards of the year of manufacture. That's pretty clear. There was never a 350 Olds certified for emissions in the A/G body cars after 1980. Thus it is not legal to perform a swap like that under federal and most state laws. The fact that the emissions equipment is present and hooked up doesn't mean that it's working properly with the larger engine. As noted previously, it is possible to sneak one by a state inspection facility, but if the tech is smart enough to catch the fact that the engine has been swapped, you won't have a legal leg to stand on.

 

[joe_padavano]

One reason many of us like the gbodys is that they were the last of the full framed cars much like a truck. A very strong platform with which you can build on.

That is unfortunately a misconception. The flat ladder frame is about the worst (well, the least weight efficient) structural design to carry either torque or bending. Aircraft designers figured this out in the 1930s. Automakers took a lot longer. Trucks still have ladder frames to facilitate swapping the bed with a utility body, flatbed, or other configuration.

Think about it. A tube is much more efficient for carrying torque or bending than a flat plate. Unibody (monocoque) cars are much more weight efficient for the same load-carrying capacity. The problem with unibody cars is that the metal gauge is not sized for the torque of a larger engine, which is why serious racers use a full roll cage (which acts as much as a structural member as it does provide rollover protection). Still, a unibody car designed for the same engine torque and HP as a full frame car will be lighter and stiffer.

 

[86Cutlass383SR]

I can vouch for the g-body frames not being very sturdy. I had an 84 CSB that my nephew and I parted out. Pulled the complete interior including dash out along with engine/transmission, front clip and front suspension. Nothing was left except bare body shell, frame, and rearend with tires so it could still be moved. It was light enough for 2 guys to pick the front of the frame off the blocks supporting the front of the car. We ran a long bar across the front frame rails, lifted, and rolled to an area where it could be hauled off. When we lifted the front up, it flexed a good 2" - 3" if not more before it came up off the blocks.

Yeah, the fenders help support the flex of the front end. But, a front clip shouldn't help support a frame. A frame should support a car, the body shouldn't be needed to support the frame.

That's why all these small braces make such dramatic increases to the rigidity of these cars!

 

[FE3X CLONE]

I agree the frames aren't very sturdy in stock form. It's one of the reasons I've added so much boxing to mine to strengthen it.
However, it shouldn't deter someone from putting a 455 (or other big cubic inch/high torque engine) into the car. The only time I could see it becoming an issue is if you start adding sticky tires, etc.