Replaced my 340 with a 392

[Cudafor36]

my fellow mopar gang. I have owned my car for the last 36yrs since I was 12. Yup. It was time to upgrade my car to the turn key capabilities. Nothing wrong with my fast 340 but I fingered why not. Given this I can sell someone my entire driveline, motor (very well built), 727 tranny, the new radiator, drive shaft, tti headers and a new firm feel power steering pump all for a low price. I have photos and videos of it running just before I remover her. Just dirty but a whicked strong motor. Txt with questions.

I would also like to offer my experience so far with installing the 392 and all the fun doing it. Lol.

 

[DetMatt1]

Just tell me that the 340 wasn’t original to the car, please?

 

[Cudafor36]

Great question and nope it was not. It's actually a '69 motor. The original owner I bought it off of blew the motor in high school racing the boys she said and put in a 318.

 

[Adam]

What did you use for motor mounts, which trans did you go with, how were the electronics and wiring?

Post more pics!

 

[Cudafor36]

I purchased the TTI motor mounts when I ordered the exhaust system. That was a mistake they make the motormouth high. Go with Schumacher ones

I Webt with the four speed auto from Silver sport transmissions. My caution in that is it was freaking really right in my tunnel.

As far as the wiring goes I am starting that this weekend. Seems straight forward enough though just lots of them. And some confusion on how to get the rpm signal. I should be able to get her.

Word of caution though.
- the pass side tti header hit my brand new motor casting at the rear. I had to grind off a tab that held the original oil pan
- do not use mopars rear sump oil pan it hits the steering linkage. I used a mildon but should have researched it a bit more for a better quality one.
- do not use the mopar 45 degree oil adaptor it hits the k frame and even after grinding off that the oil filter still won't clear. Use a remote kit.
- the drivers side tti header has one bolt that will not go in the hole due to pipe to hole clearance. I had to shorten one on the fly.
- the mopar kit for the cold air intake is too big unless you move the battery fro the stock location.

 

[tonysrt]

In your third sentence is that supposed to be "tight" in the Tunnel? As usual us Mopar Fanatics have to fend for ourselves. Unfortunately we have no choice in factory motors that fit like they should, but have to get everything aftermarket an hope that it works. And then you spend big bucks and have to alter things to fit. Good luck with your conversion.

 

[Adam]

Good info. Your tips will save others a lot of time & effort. Btw, I looked up your trans because I didn’t know what it was; that is a slick piece! Also no tail housing to crossmember interference, nice.

 

[mpdlawdog]

definitely watching!

 

[Cudafor36]

So the starter install was my first objective today. No go. Had to grind down the tab on the motor black like the other side. Also the tti header pipe is slightly hitting the starter. I'm a bit disappointed with them now.

Second words of advise are. Buy flexible tranny and oil dipsticks. The mopar one that came with the motor interfer significantly with the headers as well as the Silver sport tranny supplied dip stick honestly sucks and would not fit.

The alternator and power steering kits I bought direct from mopar fit great bit both belts they supplied with them are too long. Argh. Had to grind out a bit of the frame to install the alternator but I already new that one.

Electrical hook ups starting this weekend.

 

[dfrazz]

Not to promote another forum but I did a whole write up on my 392 swap in my '70 Cuda, including part numbers and steps. https://forum.e-bodies.org/modern-hemi-swaps/26/392-hemi-swap-2016/67/

 

[Cudafor36]

I'd love to see that. Especially since I am having trouble getting Intel on what wire to splice into for the TPS signal Timmy tranny controller. Also the rpm signal for the tranny and my new tach. Mopar was no help.

Question for ya as well would be how the motor knows the starter in in neutral or park as the new mopar kits now control the starter. No wiring to hook that into the CPU.

 

[dfrazz]

I'd love to see that. Especially since I am having trouble getting Intel on what wire to splice into for the TPS signal Timmy tranny controller. Also the rpm signal for the tranny and my new tach. Mopar was no help.

Question for ya as well would be how the motor knows the starter in in neutral or park as the new mopar kits now control the starter. No wiring to hook that into the CPU.

We used the 1970 starter system connected directly to the battery and mounted on the left side of the block, not the computer starter system. The wire harness is set up for the starter to be on the right side of the engine, so you will need to un-tape the harness and re-direct the wiring to reach the left side if you are going to mount your starter on the left side. Also, on the wire harness you can cut off and seal the starter cable connection because you will connect the positive battery cable directly, along with the starter connect for the battery on the wire harness to the starter.

PM me for a pic of how/where to splice into the tach signal.

 

[Cudafor36]

Very much appreciated. I ended up extending the starter cable to the new wires from mopar. I'll still keep in place the original starter relay just in case an issue comes up. Lol.

I'd love to get Intel on the TPS signal wire from the throttle body to a ez fast tcu for my tranny. It's only one wire to connect.

Also the rpm signal from the new wires to the tranny and to my new speed hut tach are appreciated.

Peter. 7345453794.

I'll help anyone else doing this as well. I'd recommend talking personally to someone doing this in order not to do what some have us have done the hard way.

 

[Cudafor36]

Help

Tried to start her today and It starts then immediately shuts down. Fuel pump is triggered by a switch I installed so it stays on.

 

[dfrazz]

Help

Tried to start her today and It starts then immediately shuts down. Fuel pump is triggered by a switch I installed so it stays on.

Sounds like you are losing voltage in the key run position. The only thing I can think of is that you wired the starter to the Mopar harness.

 

[Cudafor36]

Thx For the note. Yes I did wire as instructed. But it appears our old cars fluctuate volts too much for the new CPU. So I wired in a toggle switch that sources to battery. Also it feeds my fuel pump. A secret little way to start my car. Lol. The mopar kit wiring for the starter sucks, solinoid wire too small not providing enough juice. So I wires her up as original and it works great.

 

[CMC]

my fellow mopar gang. I have owned my car for the last 36yrs since I was 12. Yup. It was time to upgrade my car to the turn key capabilities. Nothing wrong with my fast 340 but I fingered why not. Given this I can sell someone my entire driveline, motor (very well built), 727 tranny, the new radiator, drive shaft, tti headers and a new firm feel power steering pump all for a low price. I have photos and videos of it running just before I remover her. Just dirty but a whicked strong motor. Txt with questions.

I would also like to offer my experience so far with installing the 392 and all the fun doing it. Lol.

View attachment 48194

View attachment 48195

How many miles on the 340 setup?

How much do you want for it?

 

[Cudafor36]

I probably have less than 5k on her over the last 12 yrs. I know I know but it's a nice weather driver.

So I told my brother for 3k he can have it all. But he is dragging his feet so to speak. Never does anything fast like moi. I took over the car when he was 23 as he was letting it sit. Now nearly 36yrs combined working on it in my possession he wants to get his own. Blah blah blah.

What you would get is
- a proven '69 340 with 450 lift and Duration balanced cam and blued crank. Bored 30 over. I would put on new seals for pan, crank, and valve covers while it's out. Does not burn a lick of oil. Can shift it at 7k rpm with no issues.
- J heads that have been ported and polished back then with a 3 angle job on em
- msd ignition system with a new position sensor in it. That sucked trouble shooting that one. Lol
- a new firm feel Saginaw power steering pump
- a new radiator, long story from a poor mech changing out my control arm.
- a strong 727 tranny. Needs front seal for sure. Long waits till I warmed her up over the years. I would while out put a new pan gasket and filter in.
- a balanced drive shaft.
- the original 340 carb cover that covers an eldebrock comp 650. That's bolted up to a performer AL manifold that matches it. No starving for fuel here. Though at 10mpg who cares.
- new clutch fan a number of years back
- tti headers. Though they show there age they work and sound great.
- all new brakes from just prior to making this plunge. I now have a wilwood system installed.
- unfortunately I just tossed the original gas tank. Wife was mad at me for holding onto the stinky thing in the garage. Argh.

Send me your txt number and I can fire off some nice clips of her before I yanked out the old.

I don't screw people. It's a wonderful motor and tranny but I wanted to upgrade and go big as well as upgrade all the wiring and misc stuff. I'd help anyway I could though my time is tight with two little ladies at home and lots of travel.

I have a borrowed lift and you can keep the engine hoist I bought to do the job. I can use it on the new motor. I borrowed the dealers new engine puller to plop in my crate 392.

I have a video of it driving into my garage prior to the uninstall and a recording of her sitting at idle that will not upload here. I'll miss the cam beat it had. Heard all cylinders explode so to speak. New one will be smoother. Car did not lobe at idle and in park as when I built the motor through Lutrell here in Toldeo (out of business now) I did not want the car "lurching".

You can call me if you wish. 734-545-3794. Peter.

 

[Cudafor36]

Oh i forgot you also get all the new and spare accel coils, ignition modules, balast resistors, and such. Don't need them anymore. You also get a nice but cheap tach. I upgraded to a Speed Hut one. It's cool. Installed it tonight

I did think of buying another junker Cuda to slap all this into for a turn key runner but after the last 35 days wrenching on the old and new stuff I said F that. My body is not happy.
It all has taken;
- three sets of pants
- seven pairs of gloves
- 50ish cigars
- two pairs of safety glasses
- three shirts
- two long sleeve shirts to keep warm as it's cold here in Ohio
- one hat
- lots of bruises
- several ounces of blood
- a couple headaches
- a trip to the ER to remove a sliver of metal to the left eye, that was scary

And lots of hours figuring out the new wiring and waiting for parts that replaced ones that did not fit or work. Heck still waiting on
* O2 sensor extenders
* bouchlin radiator hoses
* the dealer to help install the TPS and RPM sensors for the new four speed tranny
* the dealer to "learn" the tps and pedal systems

Then all this I have to "break" in the motor properly for 1000 miles. Not like my old one where all it took was a hole shot. Lol

Whew.

 

[Cudafor36]

Help. I still need some direction from dfrazz please on what wires to tap into for the rpms and the TPS signal. Also his write up is on money for the efforts it takes.

She runs and sounds great. Waiting on mopar for the o2 sensor wire extentikns for the long tube headers.

And as of last night I noticed a slight leak on the Ps gearbox. My original return line fitting (a cast aluminum part) had a crack. New one is coming in two days.

I can and will help others wanting to go through this awesome upgrade. Anyone else's ideas to tap into a TPS signal and rpm one is much appreciated.

Bates.