Engine swap questions....

I know I'm going to get flamed on this,but I'm wanting to get some answers before I say yes or no.

I have a chance to get a built 350 for free. I can also get a hold of a towing cam to go in it to get more low end torque. (It currently has a cam designed for high end hp).

The only reason I am considering this is because I know this engine. It only has about 50,000 on it, and has been serviced religously. The engine is in my dad's truck and was built by a engine builder that I have known for years and trust completely.
The truck is a 1970 full steel bodied Chevy and ran a 8.16 in the 1/8 @ 119 mph on street slicks to give you an idea of the power.


Since my dad had his leg amputated, he can not drive the truck . He is going to pull the engine and put a stock inline 6 set up with a hand throttle. He is afraid he will not be able to handle the 350 safely with a hand throttle, not to mention the mpg.


My question is... will the AW4 and 242 handle this kind of power? I can also put my hands on a 231 if the 242 can't handle it. If I have to get into using other trans and transfer case combo's, I might pass on putting the engine in my 1990 XJ

BTW....If I do this swap, I will do the Waggy axle conversion, so axles should not be a problem.

Just looking for advice. The XJ is lifted 4.5" on 33's and see's mainly trail use.

If the AW4 and te 242 are in good shape they should be able to handle the power. I have a 4.0L that I just finished building up to 5.0ish close to 300 someting horses and loads of torque. We have it on a dyno right now with the drivetrain hooked up to see if it will hold up with all the added power. So far everything is good to go.

The 242 and 231s max loads are almost the same so I wouldn't worry about the swap. A worthy idea might be to find a wrecked durango with the 242HD if you're worried about it.

.02

lancey3 said:

The 242 and 231s max loads are almost the same so I wouldn't worry about the swap. A worthy idea might be to find a wrecked durango with the 242HD if you're worried about it.

.02

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Answers a question I was wondering, because I want an HD. Thx:wave1:

mk153smaw said:

Answers a question I was wondering, because I want an HD. Thx:wave1:

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No prob =]

I dont think that an engine that can pull that hard on the 1/8th mile is gong to like having a shitty RV cam installed in it.

119 mph on a 1/8 track? Modified and obviously fiberglass C6's are running that speed on the 1/4.

That sounds like a great motor change! Please post pics after yo uget it done. :worship:

i dont think the AW4 will bolt up to the chevy... in my opinion, unless you are doing a comprehensive well-thought-out swap you're probably better off passing on the deal. at least for now.

sidriptide said:

i dont think the AW4 will bolt up to the chevy... in my opinion, unless you are doing a comprehensive well-thought-out swap you're probably better off passing on the deal. at least for now.

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Advance adaptors make an adaptor plate to hook them up.

Come on, its the ultimate redneck mod.. do it...

1985xjlaredo said:

I dont think that an engine that can pull that hard on the 1/8th mile is gong to like having a shitty RV cam installed in it.

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I was kinda thinking the same thing, but I really don't want that big of a cam for running the trails. I was thinking it would calm down the lope and improve the low end torque. Idle on this thing right now is almost nonexistant, you can almost count the cylinders as they fire.

this motor swap is alot of work. best bet is to use a tranny and transfer from an s-10 with a 4.3. if u make your own motor mounts you can also get away with stock driveshafts. i did this swap and love the power. if you have anymore questions feel free to ask.

ZacSquatch said:

Come on, its the ultimate redneck mod.. do it...

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I'm from SC, whaddy expect????

Would it make you feel better if it was an AMC 401???

Seriously, they drop them into CJ's, YJ's, and TJ's all the time...

I don't want you to feel me at all...


Haha, Throw it in man, lead by example

ZacSquatch said:

I don't want you to feel me at all...


Haha, Throw it in man, lead by example

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:laugh::laugh::laugh:


I haven't made any decisions one way or the other. I love my 4.0 but it's got 230,000 miles on it, it's the funky Renix system, and the price of the 350 is right. (FREE)

I know that there is still going to be some expense to it. Advance adapters are not cheap, the price of the waggy axle conversion, cooling issues, etc... Plus I would have to find a home for the MSD box. I don't think they like getting wet and muddy.

I'm sure there are a hundred more little things that will jump up if I do it, but the XJ's not my DD so I would have the time to work out all the bugs.

Not too thrilled about going from fuel injection to a carb setup (ugh). That's another downside. Just working through my options.

If I just had a mid 80's Monte Carlo SS or a early 90's Impala SS lying aroung with a blown motor... God I loved those body styles....

This swap is not that expensive if you use some inginuity. dont need a msd box, just a hei distributor. the aluminum rad i bought for mine was the most expensive thing i bought for mine at 250. had no choice as cooling was definately an issue.

Another source for an engine to trans adapter is Hesco. Aside from the obvious expense and the FDF (Fabrication Difficulty Factor) lies in the donor engine.....When you change the cam to the RV type, the cylinder pressure will go thru the roof at low rpm...assuming the engine has high compression pistons as it sits now....depending on how high the cylinder pressure gets you may be stuck using only high octane fuel....depends on the configuration of the engine as it is now....if you can get away with it, you will have a torque monster.

Do you know the static compression rating of the pistons and what the volume of the combustion chambers is?? Are the heads Chevy or aftermarket?? One thing beneficial is that a SBC has good quench characteristics as long as the quench is set properly...this helps tame detonation...I have built and owned several carbed SBCs over the years that ran well on pump gas at CRs up to 10:1

MudDawg said:

Another source for an engine to trans adapter is Hesco. Aside from the obvious expense and the FDF (Fabrication Difficulty Factor) lies in the donor engine.....When you change the cam to the RV type, the cylinder pressure will go thru the roof at low rpm...assuming the engine has high compression pistons as it sits now....depending on how high the cylinder pressure gets you may be stuck using only high octane fuel....depends on the configuration of the engine as it is now....if you can get away with it, you will have a torque monster.

Do you know the static compression rating of the pistons and what the volume of the combustion chambers is?? Are the heads Chevy or aftermarket?? One thing beneficial is that a SBC has good quench characteristics as long as the quench is set properly...this helps tame detonation...I have built and owned several carbed SBCs over the years that ran well on pump gas at CRs up to 10:1

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Not sure of the static compression rating of the pistons, I do know it has Keith Black Hypereutectic pistons, Dart iron eagle heads, and a Comp cams magnum 280 series cam (.480 lift, .280 duration) if that helps. I also know it absolutely hates anything but premuim gas. He is currently running a B&M holeshot 3000 rpm stall.

Just do it, have about 5 or 6 wrenching party's, cover beer cost... and we'll all help you.