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I’ve been thinking of some mods for my 403 in my Toronado. Looking for more power but to maintain the same-ish mpg. What I’ve found is that I should look into getting new heads, and then a new cam to follow that. But I don’t know anything in terms of the tech or measurements in that area. I know that it’s all super precise stuff when it comes to measuring this type of stuff. How can I adequately educate myself on this? Where should I go to understand the different numbers people use with camshafts? I would like this info so I can do my research and make an educated decision on what I want to buy.
If anyone has any tips that would be greatly appreciated.
Pre 1972 Olds 330 and 350 heads are usually used because they flow better than your factory heads and add compression. Your factory compression is less than 8 to 1. Even with .042" thick Felpro head gaskets, factory pistons .025" below deck, you will be around 9 to 1 compression. A mild cam like the base Lunati High Efficiency 207/207 cam or the 204/214 Edelbrock/Melling MTO-1 cam is as big as you want to go without more stall or better gears. Nor sure if either are available for your transaxle. Not sure if and headers or dual exhaust can be fit. Better exhaust will make a noticeable difference.
You could but it will add a lot of cost, machining, bearings and gaskets. I would do a compression test and put an oil pressure gauge on the motor to check how worn it is.
I’ve been thinking of some mods for my 403 in my Toronado. Looking for more power but to maintain the same-ish mpg. What I’ve found is that I should look into getting new heads, and then a new cam to follow that. But I don’t know anything in terms of the tech or measurements in that area. I know that it’s all super precise stuff when it comes to measuring this type of stuff. How can I adequately educate myself on this? Where should I go to understand the different numbers people use with camshafts? I would like this info so I can do my research and make an educated decision on what I want to buy.
If anyone has any tips that would be greatly appreciated.
You can up the power significantly and increase mileage at the same time if done right.
I wouldn't use any of the old school long ramp cams with excessive advertised seat duration as they grossly effect off-idle response and cylinder pressure.
Keep your seat durations low.
The best modification may very well be the hardest because there are not headers made for the Toro, but they increase ; torque, horsepower, and mileage !
A "top of the page" cam may work, but I wholeheartedly prefer a single pattern in a situation as this, unless you are wanting top-end HP increases over losing off-idle and bottom end torque. Factory exhaust manifolds hurt even the stock cam's performance. I have headers and mandrel bent duals on work trucks where the only thing that matters is torque and mileage.
Edit : don't forget to fine tune the ignition timing as it too will make a difference to be felt.
Last edited by 68post; February 6th, 2024 at 08:48 PM.
Reason: uh-huh
How difficult is it to get headers from a firebird and adapt them? I say firebird because it’s the only widespread 403 powered car I know of.
Smallblock headers are what's needed 260 to 403 will all be the same, it's the body/chassis that fits the headers.
Which yr Toro do you have ? I won't know what fits but there is a huge difference among years. Any good ones may require modifications (and that could be a severe understatement), or custom made , or just stoop to using a shorty set which is better than cast but in no comparison to full length.
I've got a '78 Toro myself, and I've been content to use it in stock form. Does yours still have the fancy computer-controlled ignition system with the timing adjusted by an engine temperature sensor? The special sensor on mine died many years ago, and replacements don't exist, but the car still runs ok with it disconnected.
I didn’t know that was an option on the toro, how do I tell if I have this?
Let's back up a bit. How long have you owned this car? Do you have a factory service manual for it? If not, that should be your FIRST purchase.
The Electronic Spark Timing system was NOT an option. It was standard equipment on all 1978 Toronados. Even though the 403 was used in Delta 88s, 98s, Toronados, and other makes such as Pontiac at that time, only the Toronado came with this ignition system. It was used ONLY for 1978, which means that replacement parts for this system, such as the unique coolant temperature sensor, are not reproduced and are simply not available unless you luck into something NOS on eBay. In my now seven years owning my car, I have never come across one.
Below I've scanned a couple of the relevant pages from the manual. I've enclosed in red boxes the most relevant parts. Note especially box 2, which describes in detail the EST system.
Box 3 shows the timing mark indicator on the engine. Note that it is not just a piece of metal with timing marks inscribed on it. There is a connector for a magnetic probe, which is part of the timing setting equipment.
In the second scan, note box 4 in the diagram at the top. It shows the coolant temperature sensor I referred to above. Note the big "controller" in the right center of the diagram. This is located inside the car under the dash on the passenger side. Note the instructions for setting the timing in the second figure here (Figure 6D-63). Timing adjustment is also described at the bottom of the second scan where I've put red arrows.
I do know that some owners of '78 Toros have ripped all this stuff out and replaced the unique distributor with a standard HEI distributor off a same-year 88 or 98.
I have never tried to set the timing on my '78 because the thought of doing all this scares me half to death. Plus, I doubt the timing is off, anyway, as the car runs fine. I prefer to let sleeping dogs lie.
Last edited by jaunty75; February 7th, 2024 at 08:46 AM.
I’ve owned the car for a few months. This is my first project car so I’ve come to this forum a few times for questions I have. I’m in the process of getting a service manual, just some resellers try to get $50-75 for it, gotta find a better deal.
Keep in mind something else before you break the bank trying to squeeze more performance out of this car. It is a 1978 Toronado. It was not designed nor built for performance. It was built to be a sound-insulating luxury barge that floats gently down the road.
If you want a performance car, sometimes it's just easier and simpler to buy one initially.
If you do end up doing anything that results in a noticeable performance increase, please keep us posted.
Last edited by jaunty75; February 7th, 2024 at 08:59 AM.
My reasons for wanting a performance increase isn’t as much because I want to just have it. I want more power because this car currently isn’t capable of taking me far away, I need this car to be able to take me about 4 hours away reliably when I leave for college (80mph speed limits) which I know the car cannot do, the most I’m able to squeeze out is maybe 70. This is supposed to be my car for everything, and I know that an old car with poor mileage is not a great decision. I was 15 when my dad bought it, and I’ve owned it for just recently. So now I’m suffering the consequences of getting a first car which was a project, but also an expensive one, it was a pretty quick punch to the face when I learned that this isn’t anything like a civic that I can get cheap parts for.
Beautiful cars! My 78 is supposed to be that shade of red, however it sat in the sun for about 16 years while the owner fell ill, so now it’s more of a light brown. But the goal is to make it look somewhat like yours. Good work!
Why can't you get to college going 70? Why do you have to go 80? Even if you could only go 60, you'll get there in good time.
Regardless of how you came to acquire this car, maybe it would be a smarter idea to sell it, get what you can for it, and buy something more practical for a college kid who doesn't have tons of money to put into the car, such as what you suggested, a Honda Civic.
I guess that more power isn’t needed, probably burning a hole in my pocket haha. I’d be hesitant to completely get rid of the car, as it is my first project, I hate to get soppy but there is definitely an emotional attachment to it. Also I have tried selling it, and people won’t pay me crap for the thing, listed it for $3,000 and most I got for offers was around $1,700. That’s when I decided to either run it into the ground, or restore it and sell higher
Getting philosophical here for a moment, 18 is a tough age to get into the old car hobby. You’re starting college, then it’s getting established in a career, perhaps getting married at some point, buying a house, having kids, getting a late-model car for the wife to haul the kids around, etc. Most people don’t get into the old car hobby until well later in life when they’ve put at least some of the these life events and life expenses behind them and their finances are a little more stable.
I didn’t buy my first collector car until I was in my mid-30s. By that time, I was married with three kids, I was about 10 years into my career, and we were on our second house. Even then, I had to watch expenses, but I found a (then) cheap old 1964 Oldsmobile Jetstar 88 for $700 and had all kinds of fun with it for not all that much money until I sold it about five years later.
My advice would be to forget about the performance enhancements, which will cost money that you likely don’t really have, and concentrate on getting the car running well enough and reliably enough in its stock form so that it really can be your daily driver, at least through college. Basic mechanical replacement parts are readily available for these cars, mostly over the counter at your local auto parts store or online from places like Rockauto, so keeping it running and driving well should not be difficult nor expensive.
The one exception to the above is the radiator. For some reason, no one makes replacement radiators for any second-generation (1971 to 1978) Toronado. Same-year Oldsmobiles that used the same engine had a different radiator that was shorter left to right as you look at the car from the front. They can be made to work, but they don’t drop right in. I did find that radiators for ‘90s era Chevy Tahoes and Silverados WILL work well and require only a minor modification to one of the transmission cooler lines to fit. I can dig up a part number if you are interested. I put one of these radiators into my ‘77 Toro, which needed a new one.
Here's a photo of the Jetstar. It was taken in the mid-90s with an actual FILM camera!
Thanks for the advice, means a lot. Thankfully the radiator was sorted, my dad got an aluminum radiator from what I think is a 79, keeps me around 185 pretty good. He probably made some kind of custom bracket for it but I don’t want to mess with it because it does the job well.
Keep in mind something else before you break the bank trying to squeeze more performance out of this car. It is a 1978 Toronado. It was not designed nor built for performance. It was built to be a sound-insulating luxury barge that floats gently down the road..
^^^THIS^^^
I have headers on my 71 98. If I were going to do it again I would stick with exhaust manifolds. You're going to pay big bucks getting someone to fabricate headers for your Oldsmobile.
[QUOTE=Luke Merrick;1551771 the most I’m able to squeeze out is maybe 70. [/QUOTE]
Please clarify: Do you mean you drive down the highway and the car will not top 70 MPH? The engine just runs out of power and with the accelerator pedal to the floor the car will not go faster than 70 MPH?
I can go more than 70, but we’re talking about highway travel. It’s not a space where I want my foot pinned for more than a few minutes at most. And so, without worry of overheating or breaking something, 70 is the most I can do comfortably
February 3rd, 2024, 04:06 PM
