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I am going to swap a GM V8 into a Jeep CJ. Looking for advice on which V8. I do not 4 wheel this Jeep. Strictly driven in the summer, on the highway and red light to red light. I am not wanting any high strung engine at all!

Wanting off idle to lower RPM power. But, want as much power as I can affordable fit within that RPM range. Currently looking at the GM Performance 5.7 Vortec long block for $3,600.

Is the 5.7 Vortec the best choice for this? Is there something better for my application in this price range? BTW, I am sticking with a carb and a distributor. Why?? I am 55 years old. Any ECM, injector, variable valve timing engine will be giving me problems in 15 years. I don't need those issues when I am 70 year old!

Please share your thoughts.
 

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Ok. The cj was never designed for horsepower.

A v8 is a tight fit and then we get to your actual wheelbase.

Now a 225 oddfire and 231 buick make good power for the size. They mate up to most 4 or 5 speeds. They came with (225)and were designed for that engine bay.

On the transmission front you may want to keep the 4 speed and run warn/saturn overdrive using the dana 18/20.

This only works in 2wd and is limited in the amount of torque you can put through it bit it is a nice option.

So far I have a pretty stock drivetrain with warn overdrive, the front driveshaft pulled, and hubs unlocked.

If you want more power a 350,sm465, and 8.8 would still fit in that wheelbase with some trimming.
 

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My take...A Vortec engine would be a good fit for you. The Vortec engines, in general, had good improvements - serpentine belt setup, one piece rear main seal, better flowing heads and better compression ratio, roller lifters...lots of good stuff that the earlier SBCs didn't have. If that price fits your budget, then it all sounds good.

SBCs fit pretty nicely into a CJ7. It's been done many times, so there is a lot of info on it. There will be a lot of details to figure out. What transmission and transfer case are you planning to run?
 

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I agree either a stock L31 Vortec or the bottom end P/N 19420294 350/265 horse engine.

The L31 Vortec has modern chambers with 9.5 or so compression, roller cam, and one piece rear seal. Currently two versions are listed 12691673 is the heavy duty unit using the 906 head with pressed exhaust valve seats, the 12691672 is the standard unit using the 062 head with induction hardened exhaust seats, there is a discontinued high performance version that was rated at 330 horse, the engines listed above were rated at about 258. These numbers are SAE net power, the cam in the two listed is roughy equivalant in timing to the flat tappet cam used in the old 290/300 horse SAE gross rated late 60’s very early 70’s 350’s. These are pretty mild as cams go but not dead sticks like those used on the 87-95 LO5 motors. Having the part number of your chosen engine is more useful than a simple description you provided. None of the L31 engines GM offers are suitable for a mechanical fuel pump as the cam used does not have a pump eccentric drive lobe. You either use an electric fuel pump or change to the marine version of this cam which has the lobe. Given today’s oil characteristics these roller cam engines are a lot less troublesome regarding cam lobe and tappet wear vis-a-vis flat tappet cams. The L31 head’s have a unique bolt pattern requiring a specific Vortec aftermarket intake for a carburetor. These engines require the one piece seal 3 inch bolt circle flywheel or flexplate.

An a side the 1987-1995 LO5 uses the Swirlport head these are real bottom end grunt engines their power is low because the port design shuts off breathing by 4500 rpm and their cam is the referenced above nearly lobe less design. These also require an oddball intake which Pro Comp and Professional Products can supply for a carburetor. As with the Vortec’s the cam does not have a fuel pump lobe and the crank uses the one piece rear seal. These respond quite nicely to a cam with any measurable duration.

The low cost choice is the part number 19420194 bottom end Goodwrench. This is the 1968-1986 design 350 it uses SMOG era head’s where low compression and slow burn chambers bring out moderate power combined with excessive fuel thirst compared to either the L05 and especially the L31. These engines use the same flat tappet cam as the old 68-73 era 290/300 horse 350’s to struggle to reach their advertised 265 horses, their reality is probably closer to 240 on a good day. This cam has a mechanical fuel pump lobe. These cranks use the two piece rear seal which tends to be leaky and take the 1968-1986 standard 350 fly or flex. These head’s use the 1955-1986 intake manifold bolt pattern. There is a version of this engine out there rated at 290 horse, it uses a lot of cam with the minimalist head’s to burn a lot of fuel for that extra power.

There‘s more but these are the big swingers.

Gen III and on engines are really nice modern designs they however are designed for computer operated individual cylinder fuel injection and distributorless ignition. They can be converted to a carburetor and there is a distributor kit but these are damned expensive mods for a guy looking to a simple solution with a carb and distributor.

Bogie
 

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An LS I would think will create a lot more torque with the right cam. And you can still carb it. With the right covers you can cover up the coils and make it look more like a small block. And when you are seventy it still won't be leaking from every orifice.

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well he did not put a size limit in his question ....ha ha

I would think , just my opinion, that a buick v-6 would have plenty of torque and fit well

I have driven a few oldies with the buick "dauntless" in them and there were excellent

I had a friend in New mexico who had a 400 pontiac in a jeep. it was tight but it hauled the mail
a pontiac 400 is the same size externally as a 455 pontiac, and it is 4 inches shorter from flex plate to crank snout than a 454 chevy
Not so with the other big GM choices there
It was only 2 wheel drive as the driveline was to long for the transfer case to fit in the driveline
That is something OP should also consider here
 

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well he did not put a size limit in his question ....ha ha

I would think , just my opinion, that a buick v-6 would have plenty of torque and fit well

I have driven a few oldies with the buick "dauntless" in them and there were excellent
You know, now that does sound like a good suggestion. If he could find one of the 3.8 blocks without paying too much.

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Yep. The 3.8 buick is a good choice, and short enough to fit the transfer behind it. Plus there are ready made adapters for your transmission/ bell housing. Should be easy enough to round up few pieces and bolt them together
 

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I sold my last dauntless 225 for $1000.
A 231 can be found for half that if you know what your looking for.

Here is the thing. Unless your replacing the entire drivetrain a v8 in a cj is not recommended. If you leave it alone at lets say 250hp and 280lbs then the rear will be fine.

But its easy to add 100hp to that then that and tear apart a dana 20 or 35.

Then we get to transmissions. Now if you want it low then you can run a th400 and stubby drive shaft.

Here is my butt.
S10 frame. 355 or 383, to a th375 with a 8.8" out back.
You can see just how easy playing with this was. I channeled the body over the rails later and was sitting on the frame dang near.
I am currently building something similar with a s10.
The s10 has a 80" wb btw.
 

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If thinking 5.7, go 383 instead for better torque.
A mild cam will run smooth and give better torque/mileage.

6 cylinders? They are not made for grunt.
 
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Something to add about the L31 Vortec. The only Vortec type roller block that I have seen that was actually drilled for a mechanical fuel pump push rod was a marine block. None of the regular truck blocks I've looked at were drilled. They had the fuel pump mounting flange, but the pushrod passage wasn't there. There was a rough drilled hole, but it didn't go all the way to the cam passage. The same goes for the early 90's swirl port blocks. I have one of those on the engine stand right now for my grandson's truck and I'm going to have to use an electric fuel pump.

Also, someone mentioned something about the Jeep rearends. The Dana 20 that came in most of them is pretty weak, mostly due to the 2 piece axles. The biggest V8 that they came with was a fairly weak smog era 304 AMC. The cheapest way around this is to find a an old Postal Jeep and get the Dana 44 axle that they came with. All of the 44's I've seen in PJ's were limited slip and the 44's have 1-piece axles. Of course, you'll have to match the front gear ratio, but that's the way hot rodding goes. You improve one thing and then there are 2 or 3 other things that have to be improved. Unless you are just planning on driving like there is an egg under the gas pedal, you will find the next weakest point in that Jeep driveline with a decent V8. Especially if you go to bigger tires.
 

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Might want to look at Summit Racing and maybe get more bang for your buck. Why buy a low HP crate engine when you can get a higher HP one? The one below costs $1500 more than the long block, but it comes complete withaluminum heads, aluminum intake, a 750 carb and a new distributor...........ready to go and with a warranty. They have other choices besides this one. Oh, and its a 383 instead of just a 350. Lot more for $1500 difference. By the time you outfit the long block, you'll have that much in the low hp crate engine.



Chevrolet Performance 19421178 Chevrolet Performance 350 C.I.D. Base Long Block Crate Engines | Summit Racing

Iron heads ,low HP................$1500 difference
 

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The thing to consider is how much torque your drivetrain can take. Be realistic about how much abuse you plan to throw at it. Having had vehicles in the past that I had to be "delicate" with, I can tell you its frustrating to have power and know that if you use it, it will spread things all over the road.
 

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you don't need torque when you have low gears---torque multiplication is your friend
I agree, but I was just responding to the OP's question about low rpm torque from a GM V8. Hard to beat 500 cubes. He also mentioned "as much hp as I can in that range." With not a ton of money he could have a (completely overkill) 450hp before 5000 rpms and an easy 600 lb-ft.
 
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