Flat head 4 cylinder power question

[Brewie212]

I have a 65 CJ 6a Tuxedo Park Park, it has a flat head four cylinder in it. I know these don't have alot of juice, but being the original drivetrain I was thinking to preserve the history of the vehicle. The problem I am having is that I was thinking of running 33"-35" tires. Now I dont know if the motor will handle these size tires, the gears are super low 5-38's so I was wondering if any one had any thoughts. I am running the original T-90 three on the tree, I would like to be able to get the truck up to highway speed 65 or so. Is this possible or just a pipe dream. Is there anyone out here running an early flat head four banger that has any input?

 

[Sasquach]

Your Jeep would not have come with a flathead 4 but an f-134 Hurricane f head motor would be original, if it has a valve cover and spark plugs on the side of the head this would be the case.
Preserving history AND running 33-35's? forget it, even if the engine had the power your brakes certainly do not and the lift required for those tires would require so many other mods history would be.....well history.
If it's a restorable CJ I would keep it close to original as practicle.
My 2C

 

[Brewie212]

Gotcha, it's a hurricane. What I want to do is retain some of the cooler aspects of the jeep, ie the chrome emblems, three on the tree, pto winch and original body lines. I am heavily modifing the frame with new power disc brakes, power steering, I am close tubing the frame and adding 2.5" wide leaf springs front an rear, moving the bomb from under my butt (gas tank). I know there is a lot of work ahead of me, I am trying to keep some of the cooler things on the jeep with upgrading the safety features. I think the oe motor is cool but I don't want to spend time and energy in something that is not efficient. I don't know anythin about the motor obviously bc I didn't even know what it was. What I want to know is if it it geared low enough will it beable to turn bigger tires efficiently enough to keep it in the game. My other option that I am considering is a late model 4.0, great motor easy to work with.

 

[Sasquach]

Dana 20 front? Closed knuckle or open? I'm thinking Dana 27 is original and to my knowledge you can not put disc brakes one that axle. Ya the 4.0 sounds good if you want to see 65mph, no amount of gearing will get the huricane to move a lifted CJ6 over 55mph and that is with a tail wind and downhill.
Not bashing the huricane, I have one myself.

 

[LongHorn]

I agree with the 55 mph limit for a lifted, oversized tire Hurricane.
A Warn or Saturn O/D unit in the Transfer Case would lower the rpm's & make it more pleasant to drive.
As far as the 4.0L goes AMC had a special short water pump, an adaptive piece used in the 1971-1975 Jeep CJ5 after that they stretched the wheelbase 3" to fit the straight six. That's why they used the optional "Dauntless Buick 225 V6 V6" in '65.

 

[Sasquach]

LongHorn has a good point, your not gona get a straight 6 in that jeep.

 

[Brewie212]

So my best bet is going to a Dauntless Buick 225 V6 v6? The front end is a 27 I have a 30 sitting in my garage with disc and power steering set up. I am currently adding mounts in the rear for the wider springs. I have not had a chance to look at the front end, I figured if I couldn't convert I would just swap. I really appreciate all the advice, I measured the AMC 258 i6 / 4.2l that I have an knew that there wasn't any way possible to fit it, but the 4.0 is alot shorter and figured with a little massaging an electix fan I could squeeze it in. I am just at the point I don't know whether to rebuild the hurricane or replace it, if I swap I don't even know what would fit. I also have a AMC 304 ? Does anyone know if that would fit easier? What would my best most efficient motor to put in without breakin the bank that would hook up to the T-90 ?

 

[Brewie212]

4bt diesel?

 

[LongHorn]

4bt diesel?

4bta is a Great motor, but way to heavy for the frame on a early CJ IMHO.

 

[LongHorn]

So my best bet is going to a Dauntless Buick 225 V6 v6? The front end is a 27 I have a 30 sitting in my garage with disc and power steering set up. I am currently adding mounts in the rear for the wider springs. I have not had a chance to look at the front end, I figured if I couldn't convert I would just swap. I really appreciate all the advice, I measured the AMC 258 i6 / 4.2l that I have an knew that there wasn't any way possible to fit it, but the 4.0 is alot shorter and figured with a little massaging an electix fan I could squeeze it in. I am just at the point I don't know whether to rebuild the hurricane or replace it, if I swap I don't even know what would fit. I also have a AMC 304 ? Does anyone know if that would fit easier? What would my best most efficient motor to put in without breakin the bank that would hook up to the T-90 ?

The "Dauntless Buick 225 V6 V6" was a factory option, so a "bolt in Swap".
The later model Buick 231ci "Even Fire" V6 is easier to find in 80's & 90's cars.
The Buick is more or less the same in mounts & bolt pattern.
It also comes with HEI ignition.

 

[LongHorn]

It's not a bolt in , but the Chevy 4.3 V6 rides in a lot of Jeep as do a lot of Small Block Chevy's.

 

[Brewie212]

What vehicles did the Buick motor come in?Models so I can keep an eye out. Thanks for the help

 

[Sasquach]

How is the 4.0 alot shorter than the AMC 258 i6 / 4.2l ? the heads interchange.
Sounds like preserving history is out the window, I'm not in your shoes but I would think very hard about keeping it somewhat if not completely original with at most a mild upsize on tires. To build an early CJ requires rebuilding/replacing about everything and put back on the market the original would be as valuable or more.
Once again just my 2C.

 

[Brewie212]

I would love to keep it, but need to be able to get it up to highway speeds. Are there any power adders that would work on the four banger? I don't need to speed just hit the limit if you know what I mean I am just not willing to sacrifice. As for resale I'm not worried about it, there are to shop owners that have been drulling over my truck since I brought her home. I am keeping all of the original equipment everything from the mounting brackets to the old springs. I know how rare this truck is and how hard it is to find original parts.

 

[LongHorn]

What vehicles did the Buick motor come in?Models so I can keep an eye out. Thanks for the help

Here are some, but there were more.
It was a Very popular engine.
This engine was used in the following vehicles:
1975–1976 Buick Skyhawk
1975 Buick Apollo
1975–1976 Buick Century
1975–1976 Buick Regal
1975–1976 Buick LeSabre
1975–1976 Buick Skylark
1977 Oldsmobile Cutlass
1975–1980 Oldsmobile Starfire
1977–1979 Oldsmobile Omega
1978-1980 Pontiac Grand Prix
1976–1980 Pontiac Sunbird
1976–1981 Pontiac Firebird
1978-1981 Pontiac LeMans
1977 Pontiac Ventura
1978–1980 Pontiac Phoenix

 

[LongHorn]

Check out this link for more info: Buick V6 engine - Wikipedia, the free encyclopedia

 

[Brewie212]

Just did some quick searches and found a 99 L67 super charged 3.8. I saw it listed on the wiki you sent me. Is that one of the bolt in ones? There is alot of info but I don't know which are compatible. The guy want $600 for motor and Transmission I don't know if that's good or not? Thanks for the info

 

[LongHorn]

Just did some quick searches and found a 99 L67 super charged 3.8. I saw it listed on the wiki you sent me. Is that one of the bolt in ones? There is alot of info but I don't know which are compatible. The guy want $600 for motor and Transmission I don't know if that's good or not? Thanks for the info

Well as they say, Yes & No.
Yes, that's the same motor, but there are complicated electrical issues to be sorted out on later model engines like this one.
No, I would bet that Transmission will be useless to you.
I imagine it's a transverse mount automatic FWD, but I'm not positive so ask the guy.

 

[Brewie212]

Just a follow up, I found a 69 Dauntless Buick 225 V6 that is gonna work perfect. Thanks for all your help guys.