70CCV

Hello Olds family, I need a little bi of help. I have a 70' Olds Cutlass CV (350). Im not a "racer" or anything BUT Im trying to get feedback on which route to go in regards to upgrading and engine (Edelbrock carb & intake or simply change the gear...hell maybe all three!!). I guess I wanna know which option will give me the most bang for the buck without watching the fuel needle move even faster than its doing now, . Fyi, engine is all stock. I get different stories so I figured I would come to the "Olds forum " for answers. I know faster is a relative word so Ill explain..i wanna be faster on the low end (coming off the stop light). Heck Im looking for any kinda feedback from you guys. Thanx in advance.

Ron

redoldsman

If it is a 2 barrel carb with single exhaust, change to a 4 barrel and some dual exhaust with some good turbo mufflers. Then change the gears in the rear end to a lower ratio. Gas mileage will suffer because that is the price you will have to pay. Nothing is free. I am sure others will offer opinions. This is mine for the most bang for the buck.

Stevec

Go gears,intake,carb and exhaust. It's easy to get caught up up in the maw's. ( might as well) going fast cost $ and like red said your gonna burn more fuel.

70CCV

Thanx for the feedback so far, Im not much of an engine guy (wish I woulda stayed in the garage with my dad when I was younger...) I didnt mention previous owner already updated exhaust (dual) & its a 4 bbl, so I guess I'll start by changing the gear. Any specific ratio better than others for what im trying to do?

scrappie

Any idea what you have for gears now? I think 3.23 is a nice mid range gearing. 3.42, 3.73 and 3.91 will quicken the pace between telephone poles.

71 OLDS

Nice color combo! Assuming you have a white top my Supreme is the same color combo but not a convertible:

driverside2.jpg

I started with the same stock setup you have and have been progressing along on this car. It's actually my son's car but he's off at a college where he can't drive until he's a senior (VMI - Virginia Military Institute) so I will continue to upgrade for the next few years.

You didn't mention your trans but if it's up for a rebuild or may be in the future you could consider having your cake and eating it too...but it will take some bucks to do it. You could replace your TH350 with a built up 2004R with the 4th OD gear, then upgrade the rear to a 3.90 posi. You will be able to spin the tires off the line, chirp the tires on the 1-2 and 3-4 shift and cruise on the hwy at about 2700 RPM at 75 MPH in 4th gear (OD) with the 2004R. All of that without touching the motor.

Just did all that to mine and now having headers, X pipe, and 2.5" exhaust installed.

-Joe

RetroRanger

thats a beauty Joe anyway you can keep and get your son another one ???

71 OLDS

Thanks Retro. I've got my own but it's also a work in progress:

NewGen5002.jpg

Here are the details on the build on it:

http://www.pro-touring.com/showthrea...ible&highlight

kitfoxdave

I would check which engine/heads you have first. If it checks out with the 7a or earlier heads, then the gear will help get you off the line. I got a 76 engine with 8 heads... and no umph! but not for long! :-)

hookem horns

Since you already have a 4bbl & duals, I would vote 3.23 or 3:42 gears for the better off stoplight oomph you want. 3:42's will have the motor spinning around 3k @70mph, depending on tire size. Would not go lower (higher #) unless considering OD as mentioned above or have bigger plans for the car. Adding an inexpensive shift kit to a TH350 will give crisp shifts and that 1-2 chirp.

70CCV

Decided Im going to pull the engine & transmission (trans starting to go)
Engine treatment: Edelbrock Performer 600 carb, Edelbrock Intake, change gaskets where I have leaks (trans, oil pan) paint engine block & bay
Trans: Rebuild & adding a shift kit.
I dont plan on doing any "might as wells" while im in there either, but depending on how smoothly this goes upgrading my brakes to discs are next.


By they way can someone breakdown my cowl tag:
ST 70 34267 BF 01093 BDY
TR 99 320C PNT
O6A 468512 850360

Also on front of engine by the water neck: 395558 2

Thanx for your help.

Intragration

Just my two cents, I'd go with 3.42s, add headers, Performer RPM, recurve the distributor and rebuild the QuadraJet. These things would provide a change you'd notice.

captjim

I agree and if I had the engine out and intake off, I would upgrade the cam. Your Cr should be 8.5 or so and the stock cam is very mild, like 194 @ .050 with .400 lift. A bump to something like 205-208 and .465 would make enough difference to justify the cost, IMO. Plus you renew the chain and gears.

Intragration

Good point, getting the engine back in only to have the chain slip when you could have done it out of the car will ruin your day. And the cam will help wake things up.

jfb

i first of all did not read all comments but here is my suggestion. I would replace the timing chain with a advancable one but first check with a major builder about your particular if any clearance issues i do not know your combos past. 2 stick with a 3.08 gear for decent mileage this will give you more cranking pressure and use what you have got efficiently i had this combo on a past car and i picked up about 4 tenths in the quarter depending on your over all condition. plus give you more peace of mind depending on what you have in your engine now and some better fuel mileage because your fuel will be used more efficiently and of course your driving style. by the way go with cloyes timing chains advancable ones.

jfb

2nd note this combo i detailed will give you more torque for a reasonable outlay of cash and ok mileage for a olds and more peace of mind. I would also like to suggest a jm 18-20 cam with this . the mileage will be about11 to 13 city depending on you and about 280 at the wheels with dumps installed and open.

captjim

Huh?? How in the world does a gear change increase cranking pressure? Do you start your car while it is rolling downhill?

captjim

The 18-20 is too big for an 8.5 to 1 350 in a heavy car with 3.08 gears and a stock converter, IMHO. I DO like the 16-18 (210/216 .472/.488) but it still might be a tad big for the combo.

Also, you did not "detail" a combo, you just suggested a gear ratio.

70CCV

Any feedback on the cowl tag information or where can I look it up myself?? I'd like to know what I'm starting with. Is there a web site? Thx

1970supremevert

http://www.oldsmobility.com/old/cowltag.htm

Sugar Bear

Consider doing a compression test and an oil pressure test before removing the engine so that you can address problems if any exist.

As others have said, I encourage you to replace the timing chain and both gears. Also consider replacing the valve seals without removing the heads. If you have to pull the oil pan to re-gasket it you may wish to look at a main and a rod bearing checking the clearance with plastigage. A suggestion, have someone with engine experience with you to do the bearing check or leave it alone if it is not knocking and the oil pressure is good. I wouldn't replace the bearings if they look good.

1970-W30

I too have a 70 convert with stock 350 and AC, and standard factory rear end ratio was 2.56 to 1.
That is what the OP probably has and in my case changing to 3.42 gears made all the difference in the world. The OP wants to be "faster on the low end (coming off the stop lights)". I would strongly consider the lower gears before cam changes, manifold changes etc. Just my 2 cents worth.......

oldcutlass

Major Power = more fuel, air + mass quantity of $$. So most anything you do to the engine will decrease mileage and take a bunch of cash out of your pocket.

The most bang for your buck would be an overdrive trans and a gear change to accomplish some off the line power to your butt dyno. This will give you a little more power to your rear wheels on the low end, while maintaining decent cruise fuel economy.

70CCV

Thanx so much for all the feedback. You guys are definately giving me some good tips & ideals.

70CCV

One more question. What can I do to get more throttle response? Example, when I'm driving and I floor it, its a slow build to speed. Thx.

stressed1

a 455 will solve your problems..

On a serious note, if you want to be quicker out of the hole stock put 4:10 gears with a posi out back. It will charge harder but will run higher RPM on the freeway. This will also alieviate your "slow to build speed" problems.

captjim

that is way too much gear for a stock 350.

70CCV

So what would you suggest CaptJim? Below are some other peoples suggetions. I really dont know how to tell what gear I have in there right now...

70CCV

What gear did you have BEFORE you put the 3.42 in, also how much did it affect your freeway speeds?

Olds442redberet

If you do everything over time you may be able to see first hand which modifications give you the most bang for the buck. Example: Duel exhaust this month, intake manifold and carb next month, maybe a cam and lifter up grade a few months after that, rebuilt heads later on, etc. (and maybe not in that order). Of course, you'll end up removing a few pieces more than once over time, but in time you'll gain more experience. I've done it both ways, and I learned more when I did projects based on a budget than I did when I pulled the motor, ordered everything at once, and then had someone else build it and put it in.
On my current car I am doing basic repairs now, with the intent of just getting it to run and stop safely. Next month I'll add duel exhaust, and an edlebrock intake soon after that. I expect to pull the heads soon and having them rebuilt as well. But I plan on spreading it out over time so as not to break the bank or take the car off the road for an extended period of time.
Just another way of doing it, and it'll give yo time to find the better deals on the parts you'll need for each project.

stressed1

How so? Its no different then a half ton truck of the same vintage with a stock 350 and 4:10's

64Rocket

If the car was a 2bbl and single exhaust, like my '70 Supreme. It probably a 2.78 rear. A happy medium would be 3.23's. 3.42's would be the next set up, but that will hurt your freeway travel, as the engine rpm's will be up there and you will be able to watch you gas gauge move very easy.
Since buying gears for your rear is not available, you may have to source a complete rear with the ratio you want. 507Olds is the man to talk to, he is on this site.
The other source would be find a chevy 12 bolt rear and almost any ratio is available.
As was said, you have the engine out a cam change would be an improvement.
The trans overhaul with shift kit will make a huge difference.
But the most bang for your buck, the rear gear change will be the way to go first.

Gene

olds 307 and 403

Rebuild the Qjet or look at the new Street Demon based off the Thermoquad. Performer intake to save weight, RPM may be a touch too much and 2" taller. You should have small dish pistons if an original 4bbl. I know Mark does a custom 208/208 on a 106 lsa. Jim used the cam he mentioned, he seems to like it. I have used the cheap 204/214 cam, it is OK but not great. Spend the money on a Cloyes Street roller set, high quality and supposedly accurate. I never degreed mine but will be on my next build. A 3.23 is a good comprimise gear with the orginal 3 spd trans. Going from 2.56 to 3.42 gears gained me .6 in the 1/8 mile.

1970-W30

The factory standard rear gears for a 70 350 4bbl Auto Cutlass was 2.56 to 1, a terrible combo for off line quickness but great for highway mileage. The rear end you have in your Olds is the type "O" differential, 12 bolt cover, 8.5" 10 bolt ring gear. it's not real easy to find gears for the type "O" differential.
I was able to get a complete 3.42 posi differential including housing and backing plates here on Classic Olds in the "parts for sale site" a while back. Like 64Rocket said, to get the biggest bang for the buck, the rear gear change should be the first thing to do, guarenteed to make a big difference.......

oldsman72

"395558 2" = '68-'70 Olds 350

70CCV

Okay, after much consideration I decided NOT to pull the engine (maybe next year)but I still need to pull trans b/c its on the way out, so ill still do the trans rebuild & shift kit with a 4th OD gear. Then from there change the rear end to either a 3.42 or 3.73 (I still have to figure out my tires, I run 275/30/20 & 245/35/19). Also, I'll upgrade my rear brakes to disc since I'm doing the rear end & of course put in new Felpro gaskets where I have leaks. Thanx again for all the info IT REALLY HELPED me figure out which way to go on "year 6" of this build. Ill do the engine work next.


By the way I have a 4bbl with duals

ELY442

If you're going to pull out the trans, dont forget to get a 2800 stall convertor. It all depends on your rear gears and cam you are putting in.

GAOldsman

This sums it up.

70 = 1970
3 = GM Division (Oldsmobile)
42 = Cutlass Supreme
67 = droptop
BF = Fremont, California Assembly Plant
01093 = Fisher Unit Body #
TR 993 = Blue themed interior w/ front bench seat
20 = Azure Blue Lower Body Paint
C = Blue Convt. Top
O6A = 1st week (A) of June 1970 Assembly date (Fairly late in the year.
468512 850360 These #'s pertain to the Fisher Body Assembly Plant build sequence and will show up in certain blocks on the build sheet.

captjim

Just to be clear, you can't rebuild your TH-350 and add a 4th OD gear. You need to get a 2004R and rebuilt it. They are more expensive. Also, it is not a direct swap.

Just my opinion, but just rebuild the TH350, get a good converter, and swap the gears for 3.42s and use a tall-ish tire. Unless you do a lot of highway driving, it will be fine. Olds engines make torque at a low rpm, you don't need a lot of gear.

70CCV

Thanks Capt, You are indeed correct, I meant to say replace with 4R and I like your suggestion but I plan on doing some road trips. Even though it will only be 4-5 trips per year I still want to have some ummmph on the freeway.
You mentioned tires...well my tire height is 26". I'm still figuring out the formulas to select the right gear for my vehicle.