54 plymouth savoy flat 6, rebuild.

hey everyone. ive had this 1954 plymouth savoy for a while now, i pulled the non-running engine out this past fall with plans on rebuilding it. i did a bit of research and i think between the work involved and the cost of machining and parts, it may be easier and more effective to do an engine/trans swap.
what do you think?
i have several SBC setups w/ auto trans already, just sitting around.
any advice or input would help out.......

 

by SBC you mean small block chrysler right?

Do some searching on here, lots of info on putting small block mopars in these cars, and lots of info on flathead sixes as well.

 

A pre-magnum carburated 3.9 V6 out of a Dakota with a non lock up 904 behind it would be a simple, cheap, dependable drive train...and cool!

 

Unless the rod is sticking through the block it would probably be easier faster and cheaper to rebuild the old motor.

Have you taken the head off and measured the cylinders? How is the crankshaft? If you do not need to bore the cylinders and buy new pistons (not necessary if there is .007 taper or less) then you can overhaul your engine for a few hundred bucks. Probably just as cheap as an engine swap even if the engine and trans is free, if you have to buy driveshaft, mounts, rad hoses etc.

O ya if you do an engine and trans swap you have to change the rear axle too, reason there is no emergency brake on your rear axle it is on the transmission, if you replace the trans you have to put on different brakes and it is just as easy to change the rear end.

Another problem is the narrow engine compartment, steering especially was not made with a V8 in mind. You can usually get around this by offsetting the engine and finding just the right exhaust manifold.

It's all according to what you want. Most guys are keeping the flathead these days, I am in this camp. But if you want to do an engine swap, and have the skills to do it, it's up to you.

 

My vote is rebuild the flathead six or replace with another one.

Ill be the first one to say....sbc is the same boring setup found in a number of plymouths. As a 53 Plymouth owner I can say that there was a time when the idea of switching it out the flathead for a V8. Then I read the number of neat things that have been done to a flathead to give it more power and more reliability. You can find speed parts for the engine, 3.73 rear ends are out there if you want(some 53-54 mopar cars came with them), OD trans units are for sale once in awhile....the list can go on forever.

George Asche in PA is a mopar 6 genius. He can talk your ear off with the information he has on making a flathead fun to drive. He has a flathead 6 set up that gets 31mpg I think. Message me for his number.

Earl "Edgy" Edgerton in CA has a overhead valve flathead 6 that did 135.6 mph on the flats. He makes speed equipment for the flathead. Aluminum heads, dual intakes and he even grinds cams. http://www.edgyspeedshop.com/index2.html

73RR on the HAMB makes trans adapters for the flathead 6. http://www.qualityengineeredcomponents.com/

In the end it is up to you. If you end up going the SBC route know you have to of set the engine about 1.25" to clear the steering box in the Plymouth. And don't scrap the flathead. You can sell it for around $150-$300 depending on the condition.

 

If you want to do a 318 it's pretty easy, I put a 318 & TF in a '50 Chrysler Royal with minimal modifications. It's got about 30K on it so far with no issues so far other than routine maintenance...

X2 on the engine offset plus I notched the RH fenderwell and heater box to clear the header and used the mini gear reduction starter from a later 318 to gain steering clearance. Kept the stock radiator and used an electric fan and it has never overheated, even in Las Vegas summer heat.

Used the entire drivetrain from an '86 Diplomat. Sent the driveline in to be shortened a few inches if I remember correctly. The rear axle bolt pattern was the same, so no wheel change was needed either and adapted the stock parking brake cable from the trans mounted unit to the Diplomat brake cables. The stock speedo cable even fit the TF

Don't forget to swap the ammeter wires when you convert it to 12V Neg Ground

Feel free to PM me with any questions.
Good Luck & Post Pics as you go

 

thanks for the input,
the original engine turned over but didnt start, i gave it a compression test and it was pathetic. the crank and pistons look ok, i already have the motor out and dissasembled. but i know i need to change out the valve seats, to allow it to run on pump gas...do they pop out or do they need to be bored out and replaced w/ an insert? the lifters were really hard to get out for some reason. the oil was gray! i dont think the previous owner changed it, ever.

 

From what I have been told, those valve seats are hardened. You do not need to change them out. I ran my flathead 6 with 103,000 miles on it on pump gas with no problem.

 

Mopar came with hardened exhaust seats from the factory in the 30s, 40s, and 50's there is no need to worry.

 

and , yes, the stearing box is right in the way...
the bores look ok but there is quite a ridge, i have a feeling the previous owner kept trying to start it, cranking and cranking, with no luck. and i did the same for a while also. after inspecting the original cam it looks as if there is a bit of wear on a few of the lobes....
i like the dodge diplomat idea, just swap the whole drivetrain over, but this involves buying another car and ripping it apart.......hhmm?

 

what do you think about post #5 from 'ETwagon'?
i just so happened to have a 92 dakota w/ 190k on it , 3.9 w/ the magnum f.i.
does this style setup still have the stearing clearance problems ? the auto trans from the dakota has an overdrive.
is this 'tried and true'?

 

Edgy can regrind that cam for around $140 i think.

 

They came with hardened valve seat inserts don't worry about it. The lifters are supposed to come out the bottom after you take the cam out. If the ridge is no more than .007" and the bores are not scored just hone the cylinders and put in new rings. If the crank is not chewed polish the journals with crocus cloth and install new bearings.

You will need to get a micrometer and measure the cylinders and crankshaft or get someone with more experience to check them out.

 

Back in the day, we used to buy rebuilt engines out of the Sears catalog, lol. They would drop ship it to the local store on a pallet all wrapped up. I would still consider having it rebuilt as parts are available for it and they run so smooth when they're done.

Bob

 

I've heard of it done... The engine will still need to be offset to the right like the V8, but you may not need to modify the RH Fenderwell (or not as much)

The OD trans is slightly larger than the TF904/998/999 trans and may have clearance issues with the floor (it's tight with the A998 on that '50 I did) I'll see if I can find the dimensions and post it for you.


The big question is... Are YOUR skills and motivation up to the task?
How much will it cost you to get an intake, distributor, and carb for your V6? All those things add up as well and nothing will kill your project like running out of $$$ or skills...

Like some of the posts suggested, check that the pieces are within service limits (or close to it) and do a quickie overhaul on the Flathead and you're up and driving without too many problems or cost...

I've seen those engines go forever (almost) with just a ring and valve job and not much else.

 

This is what it looked like when I was done...

 

Flat 6 is a sweet runner, twin carbs and pipes, real nice stuff. My first car was a 54 Savoy, but didn't have the rear fins, makes me think your car is a Belvedere with a Savoy clip, however don't know if Belvedere came as a post. Maybe a po did a mild custom. My gramps had a 51 Belvedere, it was a hardtop.

 

Rebuild the original engine. I had a 54 Belvedere when I was in college and it was dead reliable. Not a hot rod by any stretch but a pretty good old car none the less. Mine had a kind of free wheeling overdrive that allowed it to coast with out the engine slowing it down. The stock interior was much nicer than most new cars today. I wasn't crazy about it at the time but over the years I have come to appreciate just how nice a car it really was.

 

190,000 miles???? I would rather rebuild the original engine than swap in an engine with that many miles. It will last longer and be easier to do.

When I was a kid I had an uncle who always had the coolest cars. One was a 54 Belvedere hardtop, blue and white 2 tone. It must have been 10 or 12 years old at the time but it looked like it just rolled out of the showroom. I don't know where he found it but it was a neat car and I liked it.

 

ok, crankshaft bearing journal diameter is 2 1/2 (middle of the pic) in this book(1) and connecting rod is 2 1/16(top of the pic)...what does 'selective fit' mean??

 

here were looking at the bottom row for 54'(of book 2)...what does the number to the right of the 'dash mark' mean?

 

(book 1 is on the left) and (book 2 is on the right)

 

i couldnt find any wear tolerance specs for the cam. what do you think about the cam lobes?