1958 Dodge Coronet - Moving from Flathead to a V8

[IronMighty]

Another one of my numerous C body projects that I'm getting round to think about and start looking for spares for. I've got a 58 Coronet hardtop which is entry level specification with the Flathead 6 and 3spd manual column shift. I'm thinking to swapping to a V8 but keen to understand what transmission options there are if I want to retain the column shift manual?

I'm UK based so I'm a little limited in terms of what might be available(was sire tempted by a 413 for my 61 Dart that's available over here) so welcome any input whilst I search.

Many thanks in advance.

 

[mikedrini]

I'm tuned in to this build if you go through with it, so kudos to you man. Love the use of the word "whilst" by the way.

 

[CBODY67]

At one point in time, 1975 or so, a friend was looking to start a mobile photography operation and wanted a reliable car that was inexpensive. He found a '50 Plymouth sedan in a lady's back yard. Been there about 10 years or so, so he paid her $25.00 and got it hauled to his place, where we started to get it ready for use.

As a part of that, I asked the local Chrysler service manager if he had any knowledge of that car. I also asked about alternatives to the flathead 6 in it. That's when he mentioned "early Hemi" V-8s and the I-6s had the same bellhousing bolt pattern. Now, fast-forward to 2023 and some Uncle Tony's Garage YouTube segments on the Poly A motor, noting that that motor, being "early Hemi-based" had the early Hemi bolt pattern, which then carried into the LA motors' bellhousing bolt pattern. Which I also believe ALSO carried into the current Gen III Hemi bellhousing bolt pattern.

It appears a BIG issue might surface in the realm of rear crankshaft/flywheel/clutch mechanism area. There is a good bit of difference in the earlier torque converter attachment issues, so there could well be in the manual transmission clutch area too.

You might want to look at the appropriate model year factory service manual and parts book to get an idea on these things. Then possibly somebody with more knowledge of Forward Look cars than myself, in this area.

Just some thoughts,
CBODY67

 

[58Belvedere]

A 3 speed A230 is strong and has syncros in first gear. Here read this. What's An A230 3 speed - Slant Six Forum

 

[polara66hardtop]

You will have to stay pre 62' for your drivetrain, as the crank/bellhousing/clutch assy is unique to the model.
an older polyhead would work if you could find a parts car you need, mainly everything North from the bell going forward. Most people just drop in a newer drivetrain, and can the rear end and emergency brake setup that is on the rear of the transmission as well.

 

[chilsam]

I'd get a newer drivetrain ...engine and trans...GENIII HEMI n trans from a RAM...

 

[57fury440]

A lot of the old Poly motors did not come with the crankshafts drilled for a pilot bushing. If the motor came with an automatic originally you might have to get a machine shop to drill it for you.

 

[BuckeyeBarracuda]

I have an extra 325 motor from a 58 Dodge with a Powerflite transmission if any interest (Ohio)

 

[Jakter]

I have an extra 325 motor from a 58 Dodge with a Powerflite transmission if any interest (Ohio)

I would be interested if nobody has claimed it yet.
I tried to PM you but it says I reached 15 conversions and could not reach you.
I don't know what that means but if you want send me a message here.
Thanks.

 

[BuckeyeBarracuda]

Sorry that my Inbox got so crowded. Please leave me a message and I will respond ASAP.

Larry

 

[Jakter]

Sorry that my Inbox got so crowded. Please leave me a message and I will respond ASAP.

Larry

It says I reached my limit of 15 conversations and I can't leave you a message.

 

[BuckeyeBarracuda]

I cleaned mine out last night. Maybe you need to do the same? I find the cleaning of the postal boxes to be a very confusing part of the site... Let me know if that doesn't work...

 

[MAXWEDGECHAR]

Six cylinders and V-8s had different frames I am guessing because of motor mounts like the later cars with K-frames and sub-frames.

 

[BuckeyeBarracuda]

Was it actually different frames or different set-ups for the motor mounts? I have had a few 56-60 v-8 poly engines, but no 6cyl, although I know they are very different in motor mount set-ups...

 

[58Belvedere]

Frames were the same. Mount brackets were different: V8

 

[57fury440]

Like said above. No difference in frames, just the set up for the 6 cylinders. Not that hard to change.

 

[MAXWEDGECHAR]

I went to my parts manual and they show 6 cylinder frames and 8 cylinder frames. The only '58 frame shown for sixes and eights is for '58 DeSotos and I never knew they built 6 cylinder '58 DeSotos. I got into the frame differences when I wanted to set up a '59 Suburban 2 door wagon for drag racing with the 361 out of my '59 Sport Suburban.