What should I do to my Cutlass?

Oct 14, 2008
6,728
113
Melville,Saskatchewan
If there is a 4 pin connector above the the pan on the driver's side, it is a TH250C. It should be if the original trans and drops rpm around 300 rpm on the highway.
 

ssn696

Living in the Past
Supporting Member
Jul 19, 2009
4,694
113
Mid-life crisis
If this a bargain basement, teach-myself kind of project, I like your initial approach. Hope you are emissions-free in your zip code.
Find a decent 305/TH350/700-R4, preferably in a car with all the accessory brackets and belts still there. The holes are already there in the front crossmember to swap in a SBC.
The 700R4, much maligned, has a steep first gear that will wake up your car and give you an overdrive. You'll need to rig up a lockup for toque converter, check my member page for a diagram and parts list.
Next, I'd do brakes and repack the wheel bearings, then steering parts, then control arm bushings. A ball joint that lets go in motion is a very bad day.
Arrest any rust that you can get to without tearing into the body too deeply. At least paint the primered body panels with rattle can touchup paint to make it look like you're trying.
Check the body bushings to see how smuushed they are these days. You can get an inexpensive dual exhaust conversion for a SBC from Jegs or Summit. Ignore their warning that it does not fit Olds bodies, and you may have to hammer a dimple in the floor pan on driver's side if the body is ridin' low.
Upgrade to a Monte SS steering box and possibly a Jeep steering shaft.
15" steelies with 235/60-15 tires are a cheap performance upgrade.

We're talking thousands here, but you can do this over time.
An Olds 455 would be way cool, but you may be sunk into some expensive machine work. The motor mount pads can be found. The holes are there for this motor as well, so you can literally change your mind any time, as long as you don't hack up the frame.
Do not remove the air conditioning box. You can make the 455 fit with some work.

Have a blast!
 
Last edited:
Oct 14, 2008
6,728
113
Melville,Saskatchewan
An Olds 307 will work with his current trans and rear, a 455 would destroy both. Plus the big main bearings are less forgiving, people rev them and knock knock. A stock mid 70's Olds 350 is a step better than a 307 and probably won't kill a good TH250C or 7.5" rear. Also the 73 to 76 350 can built up for much more power than a 307 later down the line.
 
  • Like
Reactions: Longroof79

OldsCutlass

Greasemonkey
Apr 28, 2015
216
43
Lansing, Mi
Welcome to the forum. You got enough ideas it looks like. Money and time are always the main concern when working on a project. It would be nice of you could get your dads car then tinker with the Olds when you had time. Working and college are definately going to impact your money and time. Good luck.
 

69hurstolds

Comic Book Super Hero
Supporting Member
Jan 2, 2006
4,705
113
Upgrade to a Monte SS 442 steering box and possibly a Jeep steering shaft.
There. Corrected that for you. :) Ain't nothin' special about a Monte SS box. I know, I know...Toe-may-toe, toe-mah-toe. I think the head canon got started because of the increased availability of the boxes found on the "trillions" of Monte SS's made. So it would seem like every other car in the junkyard was a Monte SS.

I know we're a group that loves to spend other people's money on projects. I'm still of the opinion, at least for now, to get what you got fixed on the cheap as best you can so you can confidently drive the car around town without too much fear of having to walk home. The upgrades everyone has talked about are great suggestions, but at your current pay rate, it would take a good while to get your car done. And to do all that, you'll probably need more skills that what you currently have, but you can build toward that. I wouldn't get in too much of a hurry, but as most should agree, progress and results are great motivators.

There's a lot of "free" stuff you can do in the meantime. Like hooking up anything that's not currently hooked up. Or figure out why it's not. Cleaning stuff. Scrounge and trade for parts. The old school way. Inspect every inch of the car looking for water leaks or unsafe things that need immediate attention. Make a list of stuff that HAS to be done and a list of things you'd LIKE to do but can wait due to lack of $$ or time/skills. PRIORITIZE. Safety first. If it needs new brakes, re-do the brakes first. It does you no good to put a bigger engine in it if you can't stop that beast unless you drive it into a tree. If it needs new tires, get new tires.

But most of all, have fun. It can be frustrating sometimes, but if it gets that way, take a break. You should never stay mad at your hobby. That's how 10mm sockets get lost, and bolts get snapped off.
 

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
2,075
113
Upstate NY
LS it..... it the theme this week....:sneaky:
:itchy:

===================================================================================
'Run what ya brung.' At least until you can find what you're after.

If you're wanting driveable big power on the cheap, then the running (make sure you hear it run) 455 is the way to go IMO - keep your eyes peeled.

Regarding the sludge under your valve covers. Leave it alone - it truly isn't hurting anything unless you knock a bunch loose and it gets floating around in the pan. And be advised that the valley will look worse. It's really not a crisis. Just change the oil every 2000 miles for the next 2-4 oil changes and forget about it. Regarding the oil leaks and transmission fluid leaks - keep some in the truck. 'Top off the gas tank and fill the oil - check the transmission while you're at it' hehe

Good luck - Jim,
 
  • Like
Reactions: fleming442

thelifeafter245

Not-quite-so-new-guy
Thread starter
Jul 27, 2020
12
3
If there is a 4 pin connector above the the pan on the driver's side, it is a TH250C. It should be if the original trans and drops rpm around 300 rpm on the highway.

Thanks, I definitely will check that when I get some free time, no clue about the RPM's since I don't have a tach. I hope this forum allows multiple quoting or I will look a bit silly posting this.

If this a bargain basement, teach-myself kind of project, I like your initial approach. Hope you are emissions-free in your zip code.
Find a decent 305/TH350/700-R4, preferably in a car with all the accessory brackets and belts still there. The holes are already there in the front crossmember to swap in a SBC.
The 700R4, much maligned, has a steep first gear that will wake up your car and give you an overdrive. You'll need to rig up a lockup for toque converter, check my member page for a diagram and parts list.
Next, I'd do brakes and repack the wheel bearings, then steering parts, then control arm bushings. A ball joint that lets go in motion is a very bad day.
Arrest any rust that you can get to without tearing into the body too deeply. At least paint the primered body panels with rattle can touchup paint to make it look like you're trying.
Check the body bushings to see how smuushed they are these days. You can get an inexpensive dual exhaust conversion for a SBC from Jegs or Summit. Ignore their warning that it does not fit Olds bodies, and you may have to hammer a dimple in the floor pan on driver's side if the body is ridin' low.
Upgrade to a Monte SS steering box and possibly a Jeep steering shaft.
15" steelies with 235/60-15 tires are a cheap performance upgrade.

We're talking thousands here, but you can do this over time.
An Olds 455 would be way cool, but you may be sunk into some expensive machine work. The motor mount pads can be found. The holes are there for this motor as well, so you can literally change your mind any time, as long as you don't hack up the frame.
Do not remove the air conditioning box. You can make the 455 fit with some work.

Have a blast!

Thanks for the reply, I am in an emissions free zip so no worries there. As I stated before the 305/TH350 was one of my original ideas but in my area a running 307 cost about half of what similar condition 305 cost. If the TH250 will handle it, I'd like to use it since it doesn't seem to have any problems other than a few leaks and always shifts like butter. Speaking of wheels and tires, not sure if I already posted or not but I recently picked up a set of s10 rally wheels and new 14 inch tires, for about $170 all in. The car rides like a dream at 60mph. My dad and I did a decently thorough inspection of all the suspension parts, and while alot of stuff is pretty worn he didn't seem all too concerned that anything needed replacing right now. We believe the front wheel bearings are new. The 700R4 definitely sounds like an option for the future when I have more cash to spend.

Welcome to the forum. You got enough ideas it looks like. Money and time are always the main concern when working on a project. It would be nice of you could get your dads car then tinker with the Olds when you had time. Working and college are definately going to impact your money and time. Good luck.

Haha, I've been chasing my dad's caprice for years, I hope to get my hands on it one day, but it doesn't look like that's happening anytime soon. Especially after he had the trans rebuilt last year, also riddle me this its a TH350 right, I know that's the one in the car because I was there when he put it back in but it now has overdrive. He wired a switch to the center console and now it acts like a four speed. He flips the switch when he gets to about 45mph and boom, another gear. How does that even work? Do these transmissions just allow you to add an overdrive whenever you want? I was so confused lol.

There. Corrected that for you. :) Ain't nothin' special about a Monte SS box. I know, I know...Toe-may-toe, toe-mah-toe. I think the head canon got started because of the increased availability of the boxes found on the "trillions" of Monte SS's made. So it would seem like every other car in the junkyard was a Monte SS.

I know we're a group that loves to spend other people's money on projects. I'm still of the opinion, at least for now, to get what you got fixed on the cheap as best you can so you can confidently drive the car around town without too much fear of having to walk home. The upgrades everyone has talked about are great suggestions, but at your current pay rate, it would take a good while to get your car done. And to do all that, you'll probably need more skills that what you currently have, but you can build toward that. I wouldn't get in too much of a hurry, but as most should agree, progress and results are great motivators.

There's a lot of "free" stuff you can do in the meantime. Like hooking up anything that's not currently hooked up. Or figure out why it's not. Cleaning stuff. Scrounge and trade for parts. The old school way. Inspect every inch of the car looking for water leaks or unsafe things that need immediate attention. Make a list of stuff that HAS to be done and a list of things you'd LIKE to do but can wait due to lack of $$ or time/skills. PRIORITIZE. Safety first. If it needs new brakes, re-do the brakes first. It does you no good to put a bigger engine in it if you can't stop that beast unless you drive it into a tree. If it needs new tires, get new tires.

But most of all, have fun. It can be frustrating sometimes, but if it gets that way, take a break. You should never stay mad at your hobby. That's how 10mm sockets get lost, and bolts get snapped off.

Hahaha why do you think I pay the extra $10 a month to my insurance company to have towing coverage. Whenever I break down on the side of the road Jonny Tow is to my rescue. I swear they hate me, over the years I've called them more times then I can count, I make a hobby of massively underpaying for cars then I complain when they are unreliable lol. My last car cost $6 no joke. Ended up selling it for 100x profit at $600! As far as braking goes they all look and feel great, no problems there. Funny story tho, when I was younger my dad and I thought it smart to put a briggs Vtwin 16hp engine on a go kart, long story short, corners were cut so I ended up with a throttle jammed wide open, a useless braking system, and no kill switch. Thankfully the one thing that was working was the choke, I couldn't get it to stall but it slowed it down enough for me to "safely" crash into a tree. aside from a substantial dent in the frame, no one was hurt. In short I will not be skimping on brakes again.

Thanks all again
 
  • Wow
Reactions: ssn696

ssn696

Living in the Past
Supporting Member
Jul 19, 2009
4,694
113
Mid-life crisis
As far as braking goes they all look and feel great, no problems there. Funny story tho, when I was younger my dad and I thought it smart to put a briggs Vtwin 16hp engine on a go kart, long story short, corners were cut so I ended up with a throttle jammed wide open, a useless braking system, and no kill switch. Thankfully the one thing that was working was the choke, I couldn't get it to stall but it slowed it down enough for me to "safely" crash into a tree. aside from a substantial dent in the frame, no one was hurt. In short I will not be skimping on brakes again.
😬Throttle return spring on an old square body Chevy truck! there's a reason they make them in coaxial sets!!!! I was using a single, it broke at 50 mph on a back road with turns coming up. Both feet on the brake pedal, downshifting the poor auto into L1, and shut that sucker off from 5000 RPM once I slowed enough to coast to a stop. Don't do that, either!
 
  • Like
Reactions: fleming442

thelifeafter245

Not-quite-so-new-guy
Thread starter
Jul 27, 2020
12
3
😬Throttle return spring on an old square body Chevy truck! there's a reason they make them in coaxial sets!!!! I was using a single, it broke at 50 mph on a back road with turns coming up. Both feet on the brake pedal, downshifting the poor auto into L1, and shut that sucker off from 5000 RPM once I slowed enough to coast to a stop. Don't do that, either!

Wow that's crazy, it was terrifying on a go cart at about 20mph couldn't imagine a truck at 50, at least you didn't panic and knew what to do.
 
  • Like
Reactions: fleming442
G-Body Performance Upgrades

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck ConsolesDixie Restoration DepotMike's MontesP-S-TSouthside Machine PerformanceUMI Performance

contact[email protected]for info on becoming a sponsor