Her69olds

I've got a 69 Cutlass S, it currently has a 403 in it. I am ready to put a different engine in the car. I am stuck between finding a 350 rocket motor having it rebuild and slapping that in or just going out and buying a new GM crate motor(350) and putting that in. Any suggestions on what will have to change in order for me to just put the crate in? What problems will I have, will I need a new transmission, different mounts etc...PLEASE HELP!!

jcdynamic88

I would "slap" a 455 in it.

jag1886

That crate engine is going to be a Chevy engine(yuk!) and if you are going to do that there are conversion motor mounts that you will need plus every mount and drive under the hood to get whatever accessories you have to run Air PS ALT and depending on what transmission you have, you will need a new one with the proper bolt pattern.

citcapp

Depending on what you want out of it. Cruising, mild build, built for street/track. Make a choice on what you want then we can recommend the best path. Whats wrong with the 403.

The chevy 350 will degrade the resale value of your olds.

jcdynamic88

after that you will have to "slap" yourself multiple times for the huge mistake you made. find a good used big block olds 455(still not that hard to find) and forget about it.

Aceshigh

The benefit of the Olds 350 depends on the heads it comes with.......not all 350's were worthy from either Chevy or Olds.
Repeat after me.......HEAD FLOW......HEAD FLOW.....HEAD FLOW

THE most important consideration of ANY engine selection, is head flow. If it can't breathe, it's not going to make power.
So if you can find a good Olds 350 with the 68 to 70 heads (#5, #6 heads) rebuild it and you'll have far more torque with that then the Chevy motor.
Torque is where you will have more fun from a dig. My 1970 350 was dyno'd at 300hp and 425ft lbs before I sold it.

I'll answer these......

The 1968-1972 GM A-body frame was used by Chevy, Buick, Olds, Pontiac.
Chevy obviously being the most common, and "BOP" is the acronym for the last three.

So to utilize a Chevy 350, you just need the mounts for a 68-72 Chevelle to make it work.
New they are only ~$80 from Parts Place or another vendor. Used......you can get em alot cheaper.


The transmission, depends on the bolt pattern.....but more then likely you will need an adaptor or a new trans.
Tranmissions are a dime a dozen for cheap $500 TH350's and TH400's but I'd personally tell you to put a nice
$1000, GM-2004R overdrive trans in with it if you plan on driving this thing alot. Overdrives have been around 33 years now
.......TH350's and TH400's are ancient relic boat anchors IMO.

At the end of the day you should evaluate costs of any engine choice you are considering from start to finish.
IF the car isn't a highly desirable looking/condition vehicle, changing the motor isn't going to do much to the value.
Get the car running and enjoy it, and put the Olds engine to the side if you're worried about it.

firefrost gold

How is your swap ace I thought of you when i read the first few posts . I also was thinking of panos i think his name was or is might not be spelled that way but close he went with a crate engine after his 455 build went south on him I know last i posted with him he was happy with the set up I think he went with a 383 sbc crate ?

s i 442

If your going to run an over drive trans then count on a lower rear end gear change in the mix or the overdrive won't do much good unless your going to go 100MPH to use the 4th gear.
I would do an Olds 350 and a turbo 350 trans and build it strong and sounds good plus chirps the tires going into second.

Aceshigh

The 1968 came with a 215/70/14 tire ?? or a 205/70/14 tire correct ??
That put's the tire height @ just 25.30" to 25.85"

25.85" tire height with a 2.78 final gear @ 69 mph x final gear of 1.00 = ~2500rpm.
25.85" tire height with a 2.78 final gear @ 69 mph x final OD gear of 0.67 = ~1675rpm.

That's using the same rear gear, and same tire size......
An RPM drop of nearly 825rpm's = MPG savings ......it's just smart investing in overdrive technology.

Rear Gear calculator
http://www.angelfire.com/fl/procrastination/rear.html

Tire height chart.
http://www.jekylhyderacing.com/HeightofTires.htm

I updated my thread with the most recent activity.
I stopped again to install my garage kitchen cabinets and rehab my entire garage for more work space.

I'm going to be finishing my Peal and Seal interior and custom package tray with my 12" sub next.
Then I'll be putting the front end of the car back on after I weld up my T-56 cross member

Her69olds

The 403 is just worn out, it ran hot on me last spring. The car sit for 7 years before I bought it. I drove it a couple of times, she ran hot(a little too hot). The car still starts and runs, but has absolutely No power. Just ready to but something in it and drive..

Aceshigh

What is your realistic budget to get this car running ???
Be sure to separate the REALITY budget from the pipe dream hopeful "one day I'm a gonna" budget.

$1,000, $2,000.......$5,000 ??

Her69olds

Any suggestions on where to find a good 350 olds?

Her69olds

3,000 is where I am right now..

Her69olds

3k right now.

Aceshigh

Sit down, figure out what you want the car to do.....

Weekend warrior, and your only concern is driving it.
Drag strip beast that's all *****, but sucks on gas.
Daily Driver that's good on gas
Pro-Touring that's awesome on gas and can go anywhere,
Autocross, etc.

Then choose the engine(s) you might want, and price out ALL the options.
People with skills have put 5.3L LS engines in for less then that......
Just sayin, you have a WORLD of options available to you.....

Her69olds

I guess I'm just looking for a little more HP than the 403 offers, I went to a engine shop, they shot me a price of $1,600-$2,200 to rebuild. The thing that concerned me was the simple fact that the guy I don't think has ever rebuild a 403, he didn't know much about it. It was a highly recommended shop, but they haven't seen too many olds engines. In the shop.

MDchanic

Why not just figure out what's wrong with the 403 and fix it?

It runs hot: Easy enough to fix - radiator, water pump, fan, thermostat -something's not right.

No power: Maybe needs a tune-up? A lot cheaper than a new engine.

- Eric

oldcutlass

Small budget and a tough choice. I think the guys gave a bunch of good suggestions. I think you can go farther with your current 403 also. I would explore that option.

Aceshigh

Sorry!!! I was under the wrong impression that the 403 was made in the 60's........
These were late 70's emission turds and completely worthless engines.

http://www.442.com/oldsfaq/ofe403.htm

http://en.wikipedia.org/wiki/Oldsmobile_V8_engine#403

My mistake, and I apologize......throw that piece of crap out and disregard what I said before.
I mistook this for the Olds 400. I'd check the Olds classifieds for a running Olds 350 from the late 60's or 70-72.

Your budget is just very small for a ZZ4 or ZZ383 right now......
BUT.......there's other engine builders out there with 100% feedback

http://www.ebay.com/itm/CHEVY-350-38...263ee7&vxp=mtr

Her69olds

Thanks for the info and the web sites,I thought that engine was junk!! Trust me I'd much rather get rid of it.

s i 442

Then just go with a 195/60/14 and really get the RPM down.
Not everybody wants a car that looks like a pregnant roller skate for the sake of lowering the rear end gear.
I can see if the car in your sig is yours that you didn't follow your own technical tire bulletin!


Anyway to the original post question, just slow down and do some reading on this site and pick what engine would work for you.
Rebuilding the 403 would be the same as a replacement 350.
You could rebuild the 403 and put some 350 heads on it to up the compression for some real power gains not that im a 403 fan at all but its better than sticking in a Chevy engine.

75cutty455

meeeeee toooo.

Magna86

I would slow down and find out whats wrong with the 403. Could just need some attention and a tune up. Start with a compression check. The 403's are torque motors like the rest of the Olds and will put out some good power all you have to do is replace the low comp pistons and swap some 350 heads on to help. Not sure on the specifics of the 403 heads but you can research the specs to find the differences between the 2 heads. There are plenty of parts to rebuild these as they were used in the Trans Am not to mention other models in the 70's. If you swap anything other than a Olds engine you will have additional expenses for adapters, accesories etc.

Aceshigh

Here's a thread you can read up on.
http://www.v8buick.com/showthread.ph...ch-A-Pussycat&

That's easy.....smog heads and low compression from the factory
to gasp out a meager 185hp in brand new condition.

I agree, the heads being replaced are the starting point to improvement on a tight budget.

Her69olds

I just found a 350 rocket on Craigslist, I bought it today. The complete engine only $350 it even had the original 2bbl intake and carb. Not sure what year 68-72?? The #395558 2, # on the heads was 5. I will be rolling soon. As for the 403, well, just happy to get it out of my car!!!!!

svnt442

IF the engine is totally stock and untouched it's either a 68 or 69. Check the machined pad on the block just below #1 spark plug and look for stamped numbers and letters. It will be something like 39mxxxxxx
3= Oldsmobile
9= the year it was made
M= the assembly plant. This can be one of a few letters, not just M
x= the last 6 numbers of the VIN from the car that it came out of

Redog

I agree with Ace.

Everybody talks up the 403, but it needs a lot of work to be a fast engine. Cruising engine, sure go for it, but with the big valves and huge combustion chambers on the heads.

A SBO 350 would be a good option. a 395558 Block with 5 heads is the best choice. 6, 7, and 7a heads aren't bad either, but if you had to choose.

You could also go the 455 route.

Either engine the car will look factory.

As for the GM crate engine option, yeah I'm not even going to bother going there

MDchanic

A 2bbl '68-'69 350 will be a 9:1 motor. Half a point more than the 8.5:1 403.

- Eric

Aceshigh

The engine is from a 1968 to 1969 if the heads are original to the motor.
http://www.442.com/oldsfaq/ofhed.htm

First thing I would say to do is to ditch the 2BBL carb, and put on a 600-750cfm 4 barrel Edelbrock carb.
Edelbrock Performer intake also will be necessary. Headers obviously also.

The Edelbrock carbs are idiot proof, and work right out of the box and you never need to touch them.
Check out Ebay or Craigslist, people are unloading used one's dirt cheap all the time.
I liked the electric choke option but I put mine on after.


Here's the power outlay for those years.
1968 2BBL 250@4400 355@2600
1968 4BBL 300@4800 390@3600
1968 4BBL 310@4800 390@3600

1969 2BBL 250@4400 355@2600
1969 4BBL 310@4800 390@3200
1969 4BBL 325@5400 360@3600

So at best potential the motor you have now made 250hp and 355ft lbs GROSS power with only a 2 barrel carb.
Swap that intake, carb, and put headers on it.....you'll see closer to 300hp I'm sure.
My 350 responded QUITE WELL going from a 600cfm Holley to a 750cfm 4 BBL Edelbrock.

Again, you can drive this motor for 2 years before you get bored, and then you can opt to seek more power options.
Head flow IIRC was still only 180cfm at the highest.......so that still your limiting factor.

Octania

Any engine can be de-tuned and made into an overheating powerless pig.
The 403 is no exception.
In factory trim it was a great large displacement smogger motor.
With time-honored hot rodder procedures, it can be a fine motor.

Here's an idea.... compression test the 403. See if it's healthy or toast. If it has good compression, advance the timing a little, see if it runs better and overheats less....

If that works out, then you can relax a bit and take another step. Pull the 350's #5 heads and have them refurbished with W31 [BB] valves or bigger. Shave 'em 40 or so.

Assuming the 403 is not wasted, the bottom end is OK, now pull the 4A heads and the cam. carefully calculate your compression ratio and select a cam to suit after consulting cutlassefi & such experts. Put your fresh heads on, your hot cam in, your favorite AL intake- I used the factory A4 after the Performer proved to need a lot of work to fit the factory pieces... I suggest an Offenhauser offering. Might as well do headers, right?

See how you like them apples. You might be done right now. For much, much less than the cost of an entire rebuild.

Meanwhile, and/or if the 403 is abused to death, the 350 lower end can be refreshed. Your heads are already done!

I think with a good carb and your timing set right, you will find that the 403 is a very suitable engine. My example, with #6 heads, shaved and rebuilt, is very torquey. People talking shtuff about the 403, I suspect, have never had one in proper form.

kainedogg

...or you could just take a gander at Ls1tech, set that 3k aside, do a spreadsheet and assess the value of a 5.3\4l60e combo with a decent cam and stall.

matt69olds

Do THIS!

The 455 is pretty much a bolt in, will run very well with minimum mods, and will work well with the rest of the drivetrain. No brainer here!