Oldsmobile 350 Gladiator Questions

[Calamander13]

Intro:
Hey everybody. First time posting here.
I finally got my ’69 Gladiator up and running. Bought it back in October. Was in pretty okay shape. I could tell that most of the problematic rust spots had already been cut out and re-welded. Anyways, I tried to start her, to no avail. The starter was weak so I tried pulling her off. That's when I realized the clutch was stuck. So had to pull the motor. After getting a new clutch, starter rebuilt, and flipping the distributor 180, she purrs. After that I fixed the interior a bit and have been driving her lightly ever since. My 232 I6 is fine around town, but leaves a lot to be desired on the highway. 55 is pretty much TOP speed. I guess it’s just because of the nature of the low revving engine and low geared axles. I know that I COULD change my rear gearing, and then have to swap my front gearing but I’m leaning more towards an 8-cylinder solution. Enter the Oldsmobile 350.

Oldsmobile 350 in a Jeep?:
I first got the idea after looking into my father’s first car, a 1972 Cutlass Supreme. After doing some research on Buick, Olds, and Pontiac motors I realized 2 things. That Olds motors have the same bolt pattern as the Buick motors that were used in 60s-70s FSJs and that Olds 350 engines are oversquare. This allows them to rev fairly high compared to the Buick motors. I’m thinking this will allow me to cruise comfortably at highway speeds as well as make a unique “time period correct” engine swap.

This is where I’m at so far:
I was able to obtain a fully loaded engine from a 1968 Oldsmobile Cutlass fairly cheap.
I also have a friend who has a 1970 Jeepster Commando rotting away in his backyard that I have permission to rob parts from. It has the Buick V6 Dauntless and a T14 which I have already collected from the car.

It seems like I’m well on my way to make this Olds 350 swap possible. I’ve already compared the Dauntless V6 bellhousing to the Olds 350 bolt pattern and it looks like it will bolt up just fine. All ill need to do is buy an oil filter relocation kit so that I can use the Buick’s starter position.
I know I’ll also need to use the large (3”?) T-15 bellhousing spacer and long T-15 input shaft that was used to fit the V8s into FSJs.

Questions:
Will a long T-15 input shaft work in a T-14 transmission?
Do you think the long T-15 input shaft will provide enough room for a V8 with rear mounted distributor to clear the firewall?
Is there anything else I’m missing here?

Parts I Have:
Stock 1969 Jeep Gladiator: 232 I6, T14 Transmission
1970 Jeepster Commando: Buick Dauntless V6, T14 Transmission
1968 Oldsmobile 350 V8 Engine, fully loaded


Myself:
I’m a graduate engineering student and work in a machine shop so I have the ability to create some custom parts, if necessary.

Thanks in advance for the help!

[tgreese]

Quick answers -

The parts from a T-14 and a T-15 are not compatible. Completely different.

A T-14 is not strong enough for V8 power, especially in a pickup. It is possible to blow up the T-14 in the CJ or Commando behind the 225, and that's a considerably lighter vehicle. Jeep never used the T-14 with a V8. Suggest you look for a long input T-15 transmission complete if you want to go with a V8 swap. These came in the '68-70 FSJs with the Buick 350 V8.

The T-14 from a 225 CJ/Commando already has a long input shaft. The '70 Commando should have a Buick GM bell, which you could swap for the Oldsmobile bell if needed. You'll have to measure to determine if the Olds distributor will interfere. Probably it will clear fine, since the engine compartment was designed for the inline six.

IMO the oversquare engine design won't help highway cruising at all. V8 power will, but not because of the engine design.
I would point out, the 232 is oversquare by 7% already (3.75x3.5). Not to the 19% of the Olds, but not a long stroke engine.

What's your tire height? With the 232, are you limited to 55 mph because of the noise or because you are at full throttle? Suggest you attach a tachometer and look at the RPM on the highway, or learn your tire height to calculate the engine speed. There are several online calculators that will do that for you, but you need accurate input.

The Novak calculator shows that a truck with 4.27s and 28" tires turns 2818 at 55 mph. Not excessive, you could go faster if the engine is in good shape. I would point out that my '77 J10 with a 258/T15 combo and 3.54 axles does 70 easily ... it's loud, but otherwise fine. IMO you are on the wrong track if your main objective is more highway speed.

[tgreese]

Also, Stuka will clean up your multiple posts at some point. No worries. It's a feature of the forum. Submit once, and if the forum hesitates, go back. Should be there. Or wait for the forum to time out.

[Calamander13]

Thanks for the fast reply, Tim.

It sucks when you spend all that time editing your first post to make a good impression and then end up posting it like, 6 times. But thats just how she goes sometimes.

About your answers:
I'll throw a tach on it when i get the chance this weekend. Maybe discreetly mounted inside the glovebox.

I know that the T15 is the best transmission to use, but i also understand that they, especially with the Buick 350 bell, are getting pretty difficult to find. Any idea where you'd look for one? Ive frequented a handful of junkyards, seen some FSJs, but never any with the Buick V8 irl.

A few more Questions:
1. What would the length of the T15 to Buick 350 bell housing be?
2. Would a T150 be a viable solution? I know that the input splines are different from the earlier Jeep transmissions but if i have to buy a new clutch anyways then modifying my flywheel to accept that could be a solution

[tgreese]

The Jeep T-15-to-Buick bellhousing has maybe 5" extra length? I'll see if I can find a picture -



This is the 350 to T-18 bellhousing (and a T-18). The T-15 bell is similar. AMC replaced these long bells with a conventional bell and long adapter in 1971. The input shaft is about 12" long.

The T-150 would be just ok, not as strong as the T-15. The T-14 went away after 1975, and the T-150 was used in the CJs for all engines until 1980. It's midway in strength between the T-14 and T-15, and limited to 258s and 304s in CJs, '76-79. The T-150 is a Ford passenger car 3-speed, built on license by Tremec for Jeep. Ford. Short stickout, ca 6". Novak has a page about mating the Ford transmissions to GM engines. The CJ-5 needs maximally short OAL.

Would work good with its 258 for your truck, or a 4.0L. A V8/T-150 will interfere with the firewall, or put the shifter under the dash. Bending the shifter into a dogleg has been done before with the truck 4-speeds; I presume it could be done with the three-speed too.

No location in your sig. There are a few junkyards out there with FSJs. CJs too. Maybe try the other Jeep forums for discards from another build.

[Stuka]

The dupes are all cleaned up. Sadly the cause is out of my hands. I won't bore you with the technical details.

As for a transmission, personally I would not even consider a 3sp manual. Having the compound low the 4sp's of the era offered it really handy in a truck. Or there are close ratio 4sp's that could be made to work too if you don't need the compound low of a T18a or the like.

[tgreese]

Also, the T-150 may not mate with your Dana 20. Look here - https://www.novak-adapt.com/knowledge/gear-table/

This chart does not say which Dana 20 a T-14 J-truck uses. You'll definitely need the T-150 output gear, and its tooth angle must match whatever Dana 20 you use. Might work - you may be able to confirm using this and the parts book listings. Otherwise, your Dana 20's gears will be marked and could be matched to the above table.

[tgreese]

...
As for a transmission, personally I would not even consider a 3sp manual. Having the compound low the 4sp's of the era offered it really handy in a truck. Or there are close ratio 4sp's that could be made to work too if you don't need the compound low of a T18a or the like.

In this spirit, one could go with an AX15 or NV3550 and a 4.0L HO. One of these overdrive 5-speeds better addresses the OP's complaint about top speed. You'd also need a NP-pattern transfer case with passenger's side drop. The six would easily fit, and likely a V8 would work too, considering how long these 5-speeds are.

https://www.novak-adapt.com/knowledge/t ... ns/manual/

Jake's is maybe 300 miles from the OP, near Little Switzerland NC. Might be worth a look.

[Srdayflyer]

i'd look at a buick 350 instead of and olds, reason being jeep used the buick 350 for a few years if you go that route with buick you will have better support hounding parts, if you look for and engine look for a 1970 or later reason being is 1969 and earlier have a different oil supply passage internally than a 70's+ motor, the 69's and earlier have and issue with oil starvation at prolonged high rpm, as the early motors use use solid lifters and port top end lubrication thru the rocker gallery, buick changed the design in 1970 because of this reason and customers complaints at highway driving speeds and engine noise. just and fyi

[Srdayflyer]

OBTW, jeep used the buick motor because buick engines devolop their horsepower and torque at way lower rpms, compair stats and you will see their torque monster 455 produced 390 hp and 525 ft lbs of at torque at 2500 rpm , the 350 produces smaller numbers but at the same low rpm

[Calamander13]

Thanks everyone for the replys. I'm going to keep on trying to make this Olds motor work, as I already have to motor.

Stuka, I saw what you said about going with a 4 speed and actually found someone fairly close to my area selling a T-18 & Dana 20, w/ V8 3 inch (maybe 4 inch?) spacer and bellhousing from a '76 AMC 360. Seems to me like I could
a) replace the 360 bellhousing with my dauntless V6 bellhousing and fit to my Olds 350
b) (if that spacer wont mate to the dauntless V6 bell) create my own 3 inch (maybe 4 inch?) spacer to give me the room I need to fit my 350.

What do you guys think?

[Stuka]

The spacer is separate from the bell housing. So any bell housing that bolts up to the spacer, and has the correct depth for the remaining length of the input shaft, should work.

Though I am not sure on the details of which bell might work for your application.

[tgreese]

The bell from a '70 Commando is a GM part, same as used on a GM car. Its T-14 has a long input shaft and a thick adapter. Make sure it's actually a '66-70, because '71 and later are different. '71 uses a long one-piece bell, and '72-3 have AMC engines.

The GM transmissions have a ca 6" stickout, same as a Ford manual transmission (that's why you can swap manual transmissions between Fords and Chevys in many cases - see Novak's page about this). The AMC Jeep engines '71-79 used what I call the T-15 bell (AMC engine, T-14 or T-15 or T-18), which expects a 7" stickout. PN 3215152 - check the book, group 5.

The V8-to-T-18 spacer has the Jeep T-18 pattern on the transmission side, and the T-15 pattern on the engine side. NB this AMC T-15 bell is 7" deep and the 225 bell is 6" deep. They also have different patterns; the AMC bell has the square T-15 pattern and the 225 has the GM pattern.

You can possibly make a plate adapter to go from the GM bell to the V8 spacer; you have the extra stickout length needed to reach the pilot whith the plate adapter in there. Novak sells an adapter: https://www.novak-adapt.com/catalog/ada ... /kit-1415/ This will connect the GM bell to the T-15 bell pattern.

The T-18 and adapter are shown on the Jeeptech pages - http://www.jeeptech.com/trans/t18.html



Note it's more work to drive the truck 4-speed than the passenger car transmissions.

[tgreese]

Sorry for droning on about this. With the Novak kit, looks like you'd need to use the original bearing retainer with the T-18 and discard the bearing retainer they supply. I would call and ask them about this. Also, you'll need an output gear with six splines that matches your Dana 20. I'd try to get the transfer case with the transmission. Also, if the T-18 is not expensive, you should be able to flip it to an early CJ owner if you can't use it. Very popular upgrade for those Jeeps. How much do they want for it?

[Calamander13]

$500 for transmission and transfer case.
I plan on buying this then selling the commando v6 engine, trans and TC.
Also I’ll probably just fabricate my own adapter plate out since I have the ability m to.

Thanks again for all the help


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[Calamander13]

*$500 for transfer case, bellhousing and everything in between


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[tgreese]

Good price, considering how much is included. I would expect higher if the components are in good condition. Used to be you could get them for less, but they are more scarce now, and the word has been out for a long time. This combo is by far the cheapest way to put a T-18 in a pre-80 CJ. That compound low is great on the trail, even with the highway axle ratios.

In your case, this combo should work well. I'd use the existing adapter and make a plate. Hard part will be keeping the center axis aligned. 4.27s should be fine on the highway - BTDT - especially if you run some taller tires.

NP, glad I could help. Lets me express some of my otherwise useless knowledge about these vehicles. Part of my wasted youth.