Long story short, I recently inherited my dads 1970 Cutlass Supreme 2dr holiday coupe automatic with 350. The car is in amazing shape, awesome paint job, sounds great...but in my opinion it's a dog! I've been going through some of my many options, i.e., 350 stroker kit, drop in a 455, etc however before I do so....I'd like to understand how this car should/will perform? I have no frame of reference for this car or any other 70's era muscle car. This car will never see a strip or race track...it would will purely be street driven on weekends, etc and really just want gobs of torque...high top end speed is not necessary. So my question is....anyone in the San Diego area with a car built similar to what I'm looking to do willing to give me a ride!! I don't want to go down a path and then be disappointed in the end.
Thanks
Jim
Oceanside, CA

 

Welcome to the site. Sorry for the loss of your Dad. Great curb appeal to that 1970 CS.

Shoboat90 joined in June this year >>> https://classicoldsmobile.com/forums...5/#post1577794

Image below. Good Luck. Lots of great folks to help you make decisions.

 

BTW, love the Mickey Thompsons.

 

Has the car been tuned up yet ?

 

That's a beautiful car.

I had a similar problem. When a transmission expert drove my 1970 350, he told me my converter wasn't working correctly.

Replacing it made a big difference on my first Vista Cruiser.

And you probably have the 2.79 rear axle ratio. Changing to a 3.23 would help in that case.

 

Car's got some eyeball. As Ralph mentions, I would do a forensic tune and optimize what you have before you go throwing money around. You'd be surprised at how big an improvement there can be. Use that as a baseline and then report back here if you feel further "upgrades" are required.

Also, I'd be interested in hearing about your frame of reference -- the Olds is a dog compared to what?

 

Well, I don't know. That said, he was meticulous about the car, everything under the hood looks nearly new. He always just told me..."it's a cruiser"...

 

Well, I really don't know. He was meticulous with the car, everything under the hood looks nearly new. He always just told me..."it's a cruiser"

 

Noted and it seems like going this route in addition to exploring gears is my best option to start. My frame of reference is a 1997 Viper I used to own.....

 

I don't know if this helps or not, but figured I'd post it anyhow....

 

Viper V-10 ? Weight 3200 pounds ?

 

You may be setting your sights a little high, I don't think there's an Oldsmobile engine you can put in it that thing that'll turn it into a Viper. Not without spending cubic money, anyway.

 

Absolutely understood. However a mildly built 455 should produce similar if not higher torque numbers...hence my original question. Just looking for some 'grin factor' in this otherwise beautiful car....

 

Someone has done a lot of work under that hood. It is definitely NOT a factory engine setup. Edelbrock Performer RPM intake manifold, MSD ignition box, chrome valve covers, 4-row radiator, and aftermarket AC system.
With all that aftermarket stuff, there's no telling what's inside the engine and if all the pieces are mis-matched or not. For all we know you might have a huge camshaft, low compression pistons, and the standard equipment 2.56 rear gears.

 

Post a picture of the vehicle's Fisher Body data plate (Cowl) tag & members can decipher/explain week it was made, assembly plant, original top, bottom paint colors, trim & accessories if you have an interest in knowing this information.

 

I'm not an auto body expert/mechanic. I know the front fenders (both sides) are mandatory safety crumple fenders. These fenders were mandatory for the 1971 model year vehicles. I'm not 100% if any 1970 vehicles were manufactured with those fenders during the 1970 model year assembly production run. I'm equally uncertain if the Cutlass S vehicle shared the same front fenders as the Cutlass Supreme during the 1970 model year but I suspect they shared same front fenders. You'll note the "raised" ridge(s) alongside the interior side of each front fender.

 

Pre-1971 production model years had smooth front interior/inside fenders - they would have not contained the ridged safety crumple zone located on the interior/inside of the front fenders displayed on your car. Albeit, I suspect the front fenders have been replaced.

 

Mandatory 1971-Post-1971 front safety crumple zone fenders...These do not exist pre-1971 (I am aware of).

 

What does any of that have to do with performance?

 

So you're trying to compare apples to oranges.

Or in this case to a track-bred street-legal race car.

With that reference nothing you do to that Oldsmobile will make it live up to Viper performance. Sell the Oldsmobile to someone who'll appreciate it and go buy yourself another Viper.

 

@Vintage Chief lets some good detective work you've done there...much appreciated! Any info on this car is a bonus. Here's the plate, kind of tough to read though..that was the best pic I could get.

 

Thanks for your thoughts. Perhaps the Viper was a terrible reference...my bad. How about my daughters Lexus ES350..pretty confident that has more guts. I don't need the performance of a Viper...but I would like something that I can light up the tires with on occasion! I most certainly appreciate this car....IMO, it looks and sounds amazing. Just don't want to do a bunch of work and then still be disappointed....which brings me back to my original question. Thanks!

 

You’ll have to give us details about the engine and drivetrain since it’s obvious it is not a stock Supreme.
What compression ratio?
What camshaft?
What carburetor?
What transmission?
What rear gears?

If you don’t give us that information, there’s no way we can give any recommendations.

 

Well, unfortunately I don't have much of that information. Most certainly not the compression ratio or camshaft as I have no idea who built the engine and don't have any paperwork. I'm guessing it's a TH350 but haven't verified yet, I can obviously get the carburetor info and figure out the rear gears. So that's pretty much where I'm at until I find someone in San Diego willing/able to give me a ride so I then actually have a real frame of reference for what I can expect to achieve from this vehicle....until then, it's all just a bunch of numbers to me. Thanks to all for your input thus far!

 

I can tell you my bone stock 1970 Cutlass Supreme 350-4bbl with 2.56 posi would roast 225-70-15 tires across an intersection. My in-car timing with a digital stopwatch recorded 0-60 times of just under 7 seconds.

 

Likely others have not read your Newbie thread I posted a link to in Post #2. With that said and the statement you made in that thread:
Perhaps you're thinking/writing out loud and haven't really made up your mind, yet? You stated in the other thread the car has a 350 in it - but, maybe now you're not so sure since you said you haven't validated it, yet? So, some details need to be addressed so everyone is on the same page. If it's an Oldsmobile 350, referred to as a SBO (Small Block Olds) it will perform admirably when properly tuned. You need to determine what year and make 455 (BBO) block is in the basement - BPO (Buick, Pontiac, Olds)? Strictly in terms of nomenclature, the 455 would be what is generally referred to as the muscle car engine. You have some decisions to make...you going to complete this for your Dad (with the 455 block) or you still deciding based upon what you learn in this thread? You'll figure it out - plenty of smart members here to assist.

 

^x2^ My 71 350 4bbl Quadrajet w/ 2.56 rear end will scream.

If you want to determine how that car performs, as mentioned earlier - give it a complete & proper tune-up. First convince yourself what engine is sitting on those engine mounts.

 

@Vintage Chief you are absolutely right, I have not made up my mind yet! As you duly noted, I originally stated my intent was to build the 455 he had in his basement, which I verified to be an Olds 1976 block. Since that time, some things have changed and I'm obviously all over the place. Based on some of this info you and Fun71 have just presented, maybe I incorrectly assumed the car has a 350...I guess I need to verify that first and if so, ensure it's tuned properly before moving on to the next step. So for now, my thinking out loud has paid off and for that.....I thank you all for your input. I'll report back with what I find. Enjoy the weekend my friends.

 

350, right?

 

I believe that's correct. Olds 350 block from 1968-1976.

 

ST70 = Style 1970 model year
34257 = Oldsmobile (3) Cutlass Supreme (42) Hardtop Coupe (57)
E = Linden, NJ assembly plant
9396? = Fisher Body Works Sequence Number
TR970 = Black Vinyl Bucket Seat Interior
WA4035 = Nugget Gold paint
04E = Built Fifth Week (E) April (04), 1970
B85 = Belt Reveal Molding

I don't see either BDY or PNT (Body or Paint) codes listed for lower body color &/or top color. Yet, others have noted slight discrepancies in both the Linden Assembly Plant & the Fremont Assembly Plant Cowl Tag stampings.

You can validate the build date (04E) is correct if the paper VIN sticker is still attached to the inside of the LH (Driver Side Door). It should be blue.

 

Your car is probably a mis-match of performance parts, an or the cam timing and ignition timing are incorrect. And the carb is not tuned correctly. Ive had 3 1970 Cutlass Supremes(one convertible), all with the standard 350 4bbl 310HP motor, T350 trans, and 2.56 rear axle ratio one with anti-spin. and all 3 could smoke the tires from a dead stop. And each of these cars weighed in the 3800 lb plus range.

 

Yes, but were they as fast as Vipers?

 

of course not, missing 2 cylinders and 138ci, 1st gear is way different(2.97vs 2.54), axle ratio(3.55 vs 2.56), and weight (3200lbs vs 3900lbs)

 

I know, right?

 

Google has a 97 viper going 12.1xs at 119. That's a lot of MPH for a 12 second pass so I'd guess mid-11s with the right driver and track.

Either way those times can be matched easy enough with a cutlass. I wouldn't expect it to handle the same though!

 

THanks for this info...I was wondering what the paint code was..

 

I'd suspect that to be the case based on feedback from three of you folks here stating you all had similar/same vehicle with standard 350 and other similar components. I was out for a cruise yesterday and there is no way in hell this car is smoking the tires from a dead stop!! Sure does look and sound good though. I'm firmly in the category of 'all bark and no bite'.....

 

FWIW, it has a Summit 600cfm carburetor

 

I had a similar Holley 600 on my car in the 80s. The car ran well with it, but it took a lot of tuning to get it to run the same as the QuadraJet. Then I went on a road trip and got 10 mpg on the highway. The QJet went back on after that and I gave the Holley to a buddy for his Camaro.