Gen III Hemi and transmission

[ejkisling]

Hey there,

I’m planning to install a Gen III Hemi engine along with an automatic transmission in my '67 Sport Fury Convertible. Do you have any recommendations for a good automatic transmission choice? As you may know, there are quite a few options available with the 8HP70 attached. I'll be using the car primarily for cruising and attending local car shows—no racing or drag-strip events!

Thanks!

Skip

 

[CBODY67]

There's a thread in here of such a swap in a '66 Newport, engine and trans. I think a trans controllers is now available separately?

Same bellhousing bolt pattern as an LA motor, so you can rebuild a 904 to HP standards or find a LA727 model.

An OLDer thread on a '67 Sport Fury with just a Gen III upgrade. That thread is useful as it uses the Gen III radiator and such, which is very easy to adapt to the earlier core support! Using the Gen III OEM coolant tank and CAP can be good to do!

An issue might be which rear axle and which ratio is in it?

Just some thoughts,
CBODY67

 

[Sixpactogo]

There are lots of things to consider. If mileage is a concern, you may want to consider the 5 speed Nag1 or the 5R45RFE truck transmission. Both of these transmissions will require widening and raising the hump. The Nag1 requires using the Nag shifter and uses a transmission controller. The truck trans is a stand alone unit that don't need either. A lot depends on how much money and work you want to donate to the cause. Post 2 with the 904 will be your cheapest route.
I wanted more miles per gallon and an engine that will run fine on the junk gas these days so I opted for the 6.1 and 5R45RFE in my 68 Charger because I wanted a stock looking car for the most part. The aftermarket has stepped up to the plate making any way you decide to go doable and there is a lot of help out there these days compared to when I did mine 10 years ago.

 

[ejkisling]

Thanks Guys,

I planned on using my 8 3/4 with a new dropout from Quick Performance (Yukon Nodular Iron 489 Case,3.23 gear ratio, 33 spline Eaton Truetrack) Yukon high alloy axles.
I am committed to the Mopar 8.75 since I've purchased 4-piston rear disc brakes.

Is there any way to retain my factory console and shifter?

Thanks again,
Skip

 

[66 Monaco 500 365]

If you use an overdrive trans, 3.23 won't work well, you will have to be going 90 to use OD.
My $.02

 

[CBODY67]

With the Gen III and the factory automatic, many of them came OEM stock with approx 3.23s in them, so the EFI and such can keep the lower rpm at cruise under control. The EFI is the key, though. The bulk of late model GM cars and light trucks run approx 1700rpm at 70mph in OD.

FWIW,
CBODY67

 

[Sixpactogo]

Thanks Guys,

I planned on using my 8 3/4 with a new dropout from Quick Performance (Yukon Nodular Iron 489 Case,3.23 gear ratio, 33 spline Eaton Truetrack) Yukon high alloy axles.
I am committed to the Mopar 8.75 since I've purchased 4-piston rear disc brakes.

Is there any way to retain my factory console and shifter?

Thanks again,
Skip

I used my factory console and shifter with the 5R45RFE truck transmission. You could use yours with the 904 or the 5R45RFE but not with the Nag1. The Nag requires its own shifter. I saw one guy in FBBO that was able to fit the Nag shifter into his 68 Charger console but it won't look stock. Here is a pic of mine. 2" higher than factory but no one notices.

 

[Sixpactogo]

If you use an overdrive trans, 3.23 won't work well, you will have to be going 90 to use OD.
My $.02

I have a 3.23 sure grip in my 68 Charger with a 6.1 and 5R45RFE transmission. It actually works very well with the overdrive. The first two gears of the 5 speed are lower than first gear of a 727 so you get the grunt off the line you would with the 727 and 3.55 gears. Plus in 5th gear, my Charger turns 1750 rpms at 70 mph giving me 20+ MPG. Perfect for hiway driving for me. If I were racing it, maybe 3.55 would be a better choice.

 

[Just Carbs]

I have a stock 5,000-pound 97 Dodge B2500 conversion turtle top van with the 318 and 4 speed auto overdrive. That van shouldn't (don't do it) be driven over 70 mph, so the overdrive is of no use in that vehicle with that rear. At 80 it can be used, but at 70 it shifts a lot.
My 98 B3500 van 4 speed auto 360 motor 3.91 rear is fine at 60 plus.
My old 3,900 pound 92 Dakota 6-cylinder, auto overdrive was fine with the 3.15 rear at 60 plus. But not in town.
Seems wind and weight have much to do with the rear gear and overdrive.

 

[ejkisling]

Does anyone know of an 8HP70 transmission cross-member mount for the 67 Mopar C-body that is being made

Thanks,
Skip

 

[ejkisling]

I used my factory console and shifter with the 5R45RFE truck transmission. You could use yours with the 904 or the 5R45RFE but not with the Nag1. The Nag requires its own shifter. I saw one guy in FBBO that was able to fit the Nag shifter into his 68 Charger console but it won't look stock. Here is a pic of mine. 2" higher than factory but no one notices.

View attachment 690418

Thanks for the photo! Looks great!!

 

[CBODY67]

Might be mention of that in the '66 Newport swap?

 

[BlueGhost]

How do you plan on controlling the engine and transmission? I know Holley's Terminator X Max can control a 46RE. It controls TC lockup, OD shift, and line pressure. Shifting the first 3 gears are done via the TV cable.

 

[ejkisling]

There are several aftermarket controllers available. I haven't decided which one I will be using.

Best,
Skip

 

[wyrmrider]

I had 2:94 gears in my 69 polara coupe 360 magnum and 518 worked fine
great out on the freeway LA to Vegas custom torque l U converter
Transgo kit

 

[Darby]

If you use an overdrive trans, 3.23 won't work well, you will have to be going 90 to use OD.
My $.02

I have a .68 od Tremic behind a 440 with a Sniper-2 in my '65 SP. My 3.23 gears were like new so all I did is add a Yukon Power Lock limited slip unit during the rebuild. Doing the math with the 275/40/17 tires will have the rpm's at 1,950 at 70 mph. It's not legal for the road until next summer (I hope), but I have several miles on it and it takes off well and feels great. I really feel the 3.23 gears are going to work great. On the dyno it passed 500 ft. lbs. at 2,700 rpm's so with that kind of torque, I think the od with 3.23s will work as well as my Mustang GT convertable (5.0 5-speed) and 1500 quad cab Dodge Ram that also had a 5-speed manual. 70 mph was 2,000 rpm's on both of them, that's pretty common.