Hurst 307 or 403 for a Custom Cruiser....

Hello,

I wanted to ask if anyone has fitted a Hurst 307 into an Oldsmobile Custom Cruiser wagon?

The stock 307 I have in my 1988 wagon is underpowered.

I want to keep the Computer Command Controlled Quadrajet Carburetor if I can.

Also, if I move to California could this be an issue? I'm currently in an area were there is no smog testing requirements.

I have thought of putting in a 403 with 350 #5 heads from 1968/69 and again keeping the CCC system but thought that might be the more expensive option.

I'd appreciate any comments.

Thanks

Join the club. I have been researching this for at least a solid 1-2 years (mainly cause I haven't had the budget to start yet). This is my opinion.

I have the same issue with my 1989 Buick Electra Estate. She is smooth on the highway, but takes an age to get up to speed. I probably get worse MPG revving her to get up and going with my 2.93 peg leg rear.

The CCC is the entire system. This includes the computer, distributer, carb, sensors, and a lot of vacuum hoses. You have a later model which means you also have the Knock Sensor and the CCC is responsible for activating the lockup torque converter of the 2004r transmission. If the whole system is working then it is great news for keeping the current engine in good running shape while maintaining decent mpg for an underpowered V8.

Swapping to a 403 is very straightforward because all Olds engines have the same engine mounts. The 403 is also a short deck SBO, so the accessories and brackets will swap over no problem. If you were keeping the 403 stock, then the CCC should run without any issues. One thing about the computer is it doesn't know the size of the engine it is regulating. Only the sensors and the computer maps in its brain. So 5.0 liters to 6.6 liters is doable.

THIS IS THE ISSUE. The CCC is good to manage a stock motor, but not so much a hopped up one. That is the big limitation. Going to a 403 in stock form is a 40 HP and 65 TQ upgrade over the 307. It was around an 8:1 CR and bumping it to 8.5 would work with little problems and a small boost in power. The CCC responds to good vacuum and low compression. When the compression ratio starts to rise, problems start occurring. Since it isn't programmable, a laptop can't be plugged in to reset the timing advance or the spark maps. Its PROM stuff that isn't really used as much. And the CCC and PROMs for the Olds systems are different than the Chevy equivalents.

I have been on this exact path since I wanted to drop in a 403. After a while I considered a tall deck 455, ditching the CCC, but upgrading to a TBI or even a MPFI system. The TBI is essentially an electronic carb and, to me anyway, seems like the modern equivalent of the CCC. Going to regular a non-CCC Rochester carb seemed like a step backwards. You also lose the cold starts, fuel metering, and engine management (no matter how rudimentary it was). This when it starts to get expensive on whatever path you take. Tailoring to the CCC, if you want a lot more power, didn't make sense from how much it limited the motor. If it was a stock swap, then it'd be fine.

With the 307 HO, the computer is also different so that would be swapped as well. My issue with that swap is the gains don't feel like it could justify the cost. Swapping the 403 still leaves room for improvement. Maybe if you decide to ditch the CCC or upgrade something in the future, it can be done. The 307 HO doesn't allow for more upgrades after the swap.

For now while, I'd recommend dual exhausts. You can make the 307 breath a little better. Rear gear would be the another option, but I wouldn't recommend that until you know the engine you want. Also make sure the 200r4 transmission is healthy to handle the addition stress.

I can't comment on Cali, but I it is a heavy Smog state. That means the CCC and AIR system and Cats will need to be retained. The good thing the 403 is identical to the 307, so no one would notice in a visual inspection. Considering how many of these exist I'd be surprised if they knew better with a 455.

Again, this is just a quick glance at my opinion. I'm not an expert and I'm sure I left out a few things. This is just info I've gathered and thoughts I've made over the years. The CCC was a good system for the time. Mods to it are difficult due to its antiquated nature.

I hope this helps or gives some insight to your project.

Always more cubes. You may have a few small issues with a computer controlled car when changing engine sizes without reprogramming the computer.

Old guy quote,"There is no replacement for displacement." No disrespect for current or past aged members of this fine forum.

Not to hijack, but, I've been scullin' on swapping a 500 cuin Cadillac into my '89 Buick. Can it be as simple as bolting the big girl in, swapping the CCC quadra flush to the stock caddy intake and transferring as much of the vacuum stuff and sensors required to keep the confuser satisfied ?

I have several 500's and 472's on hand as well as a 582 cuin. Ground shaker  (left over from my 9 sec, bracket dragster)  Factory 472 exhaust manifolds should clear everything, but a set of custom shorties would help the bigun' breathe at cruise...1300 RPM @ 70 MPH, anyone?

Sound's like a "go big or stay home" kind of thing... When I was living in commifornia I was military non resident, all my vehicles registered in my home state, no smog pains, I don't think that is an option for you, but there are other options.

Paul

Even a 455 would be a good option.

you'll need to rejet the carb for the extra 193 cubes,.

Or drop an LS in there, seems to be a popular swap on the tbi 90s wagons....

Red, if you have a Caddy big block sitting around (or three), definitely consider dropping one in. Personally, I would pick a low compression 472 or 500. The TH700R4 might live behind it with an adapter plate, and the stock ratio rear end will be ok (especially if it's a trailer pack car). Also, I'd completely scrap the CCC and just go with a non-computer Quad for the stock Cadillac application.

Jayoldschool,
The BB Caddy (472/500) will bolt right up to the 4 speed auto in the wagon, (BOPC pattern) the rub is getting the lockup torque converter to work. (I have several different converter bolt pattern ring gears on hand) I've not yet figured out exactly what sensor point (vacuum pot/point, solenoid, etc.) tells the converter to lock and unlock, or precisely how the tranny shift's are controlled. There are way's to beef the 4 speed, to better handle the massive Caddy torque.

The advance weight plate and the module in the 307 olds appears to be the same ones as my '76 caddy HEI. Further investigation is needed but what I really need to learn is how much control is in the distributor/CCC and how much is mechanical/vacuum.
Still sounds doable, That said, a short tail TH 400 and a mechanical QJ might still be the easy way out, but I hate to lose the OD...

Thanks, Paul

There are ways around that, the early 700R4-equipped S10's had a vacuum switch to control lockup, which worked in conjunction with the brake pedal switch and the 4th gear switch on the trans.

Ahh here we go : http://www.73-87.com/7387garage/drivetrain/lockup.htm

That would likely be the cheapest route, and also easy since the car is already wired up for the overdrive.