Can I get some opinions.

OK I have a 1946 dodge custom four door. It has everything original. The Flathead the trans all original. I am fighting with myself on going with the Flathead or putting in a 350 engine turbo 350 trans and 67 camaro reared. I did a re ring on the Flathead it has 70 psi compression which is low so it will need to be rebuilt maybe. So I know it will cost a little money. Now I think going with the Flathead would be cool and give a very unique look. But I do like the fact that I can walk into the store and by Chevy parts off the shelf to fix the 350. If I go with the 350 I am planing on using a front motor mount to mount the 350. Now the car is not going to be a full high dollar restore. It will be more of a rat rod hot rod. I do plan on keep four drum brakes. Keep in mind I don't plan on racing this car. Thanks for any advice.

 

Might just get a quote for a rebuild then weigh your options.those flatheads get pretty good milage and can be pepped up a bit.Rat rods are kinda looked at here as shiboxes ,be kind to your car.

 

You have come to the right place, there are a lot of opinions here. First I would not use the word rat as this isn't the place for those and you wont be taken seriously. I would use the flathead, rebuild it and enjoy like you said your not going to race it so the it will cruise nicely with a fresh rebuild. Good luck.

 

I'd use the flathead also. I think it would be much cooler to keep it that way.

Also, it would be a lot of work to change the whole drivetrain with different parts.

 

I apologize for the use of rat rod. Lets say low budget restore. It is a nice car so it really is no rat rod. I do like the idea of the Flathead you don't see to many of them anymore. This is what I know so far. rebuild the Flathead 500 to 600. Using nos parts. 200 for hei distributor. 280 for webber carb kit. So maybe 1000 to get the motor going. Now the 350 motor and trans and rearend will cost 300 from a local guy by me. He said motor ran but will need to cleaned up. Trans and rear end is good. Im not looking for crazy power. But I would like to pull out in traffic and keep up. I have never rode in a car with a Flathead so i don't know what kind of driving you can do with it. Now when i add a little oil my compression goes to 90 psi. maybe the new rings need to break in. does anyone think maybe i can use it like this and see how it goes,or just rebuild it anyway. Thank you all for your advice.

 

What do you mean "add oil"?, to the crankcase, or putting some in the cyls? How many miles on the rebuild? Personally for less than a Grand you could probably find a decent running Dodge Van or pick up with a 318 in it & drop that in.

 

I DO know how your flattie is going to be in traffic, and I don't see you being happy. Chryslers were not fast. And that was back in the day.

Cosmo

 

I think the Flathead is the way to go in the long run if you're going for a Traditional Custom. Find yourself a book on them if you can and figure out how much of the work you can do to save engine shop time (is money).

Start yourself a list of what the engine needs and what you want for it and start shopping around for the best deals.

If you really want to do a V8 swap, I strongly encourage you to keep it MOPAR! Grab a cheap 318 and drop a 4bbl on it, 727 (or A518 for OD) Transmission, and a Dana rear end with 3.55's. That would probably bump it out of the period-traditional arena, but it would still be damn cool. You could score a setup similar to this (if not exact) out of an old beater RAM 1500 (or a Van like George suggested) for short money. 318's are great engines and there are speed parts for them.

 

George... I put a little oil in the cylinders. It has no miles on rebuild. I have just been testing it on the ground. I checked compression after build. I was not happy with the results,and i figured maybe it needs to punched out and rebuilt. I could be wrong. I might need to give it time to break in.

cosmo... How slow is slow.

 

"How slow is slow.?" Like the smell leaving cat shit. Go with a V8.

 

Keep a few things in mind.
1) The cost to rebuild or even hop up the six will be far cheaper and quicker than the cost to completely customize the installation of a chevy V8 into your car.
2) If you use the 67 Camaro rear end, you will have a 5 X 4.5 wheel pattern up front with 5 X 4 3/4 in the rear which means you will have wheels that will be hard to match.
3) If you ever want to sell, Mopar guys do not take kindly to non-mopar engines so your car will be harder to sell.

You may want to read this post from the HAMB as well as it is very similar answers to your question: http://www.jalopyjournal.com/forum/showthread.php?t=828364&highlight=plymouth

At the end of the day it is your car and you need to be happy with it. Flathead sixes sound cool as hell with straight pipes but will not win any races. There are several threads on the HAMB about putting a Chevy S10 T5 tranny behind the flathead to make them a little more modern driving friendly with 5 gears.
You posted your question in the traditional custom portion of the HAMB and will probably receive answers that lean that way. It will probably get moved to the main board in the traditionally styled section.
Good luck with your car and post up some pics as you go.

 

I posted some pictures under my account if you guys would like to view them.

 

Run the engine you've got and put a hot drivetrain swap on the backburner so you can focus on getting the car to look the way you want, handle and stop better first. Buff out that paint, address any rust and start thinking about your wheels, stance and interior. You've got a nice, solid looking, and running car there from what I can see.

 

I run a rebuilt flathead in my 1948 (avatar). Split exhaust and 3 1bbl carbs. 17mpg. Cruises at 60 mph. I like it.

 

Does the Dodge in question have a regular 3 speed stick, or is it Fluid-Drive?

With a regular stick trans, you could swap out the rearend for one with a better gear ratio (and eliminate the Satan-installed brake drums in the process) and you could cruise 65 comfortably. That would seem like a good compromise to me.

But I fucking hate Fluid Drive. It robs power that the engine doesn't have to spare anyway, and it's only 2 speeds. If that's what you got and you want to run the flat 6, consider converting to a regular stick shift, or just swapping out the whole drive train.

That's my opinion, anyway.

 

This one is a good answer.
The OP asked how slow, slow is. If its the fluid drive the answer is "very slow", but with the stick transmission, it wasn't any worse then anything else built at that time. I drove a Chrysler with the flathead 6 and a stick. I was really surprised how responsive it really was! It will keep up with most cars on the road today right up to about 70mph, as long as your not going to race. The flathead made quite a bit of torque at low RPM, and torque moves the car. A modern rear axle will give you tolerable rpms at highway speeds, look for a gear ratio in the 3:23-3:55 range. Split intake with 2-3 1bbl carbs and split exhaust manifolds with dual exhaust improve the low to mid range power. They don't like, or do well at over 4,000-4,500 rpm. With the proper gearing, they will cruise all day @ 65-70 mph.

The flathead 6 was a good motor, Mopar used them in production cars up to 1960 and they were used as industrial motors for farm equipment and fork trucks into the 70s.

What would i do? My current 48 Plymouth has a Dodge V6, 5 speed, in it, as did the last one (in fairness, neither had a running flathead 6 in them). But the 3 before that all had 360 Mopar v8s that I put in them. I was a motor head, now I'm just an old man. Gene

 

Flathead! If you want to go V8 put a Mopar in it! At least it will be unique.

 

Be different. Don't go with a 350.

 

383

 

Let's see if I got this right. You have rebuilt the flathead and don't feel the compression is high enough. My opinion, you have gone this far, put it in the car. I know the slant sixes were gutless, can not imagine the flathead any better. But I like the unique and the flathead will probably stand up to anything you can do to it but fast it isn't.

I like the car. Fix it up and give it some polish.

Neal

 

The word budget is key. Do the friends combo sbc/turbo trans. If the MOPAR boys WANT it kept all MOPAR, they can step up with the (near free) drive train AND help w/ the swap.

 

If you think you're up to hacking and sawing, drop that SBC in there. Look at all the attention you're getting by just mentioning it! The hell with the MOPAR guys. They don't have to build OR drive it.

Just don't call it or build it like a rat rod.

 

I'd leave the flathead in it, and drive it for a while. If you don't feel the need for speed after that, it will suffice for you. There are a lot of options to upgrade the engine (including a SBC) if you need more power. These are great cars, but the engines aren't exactly powerhouses. Certainly adequate in their day, but not any more if you drive on interstate highways or turnpikes. For a cruiser, they are fine. But if you want to easily keep up with highway traffic, and have the reserve power to lead the pack, then a V8 is what you need.

 

Yes! Join the sheep heard with yet another car with a bellybutton V8!

 

No bellybutton - put a 318 or 360 with a 518 - easy to find with the rear sump pan you will need in many pickups in the wreckers and as cheap as a chev. Easy to build a bunch of power cheaply and tough motors, and best of all, keeps your ride all mopar. Many threads on how to swap it in there on the HAMB.

 

If dependability is your goal and the flattie isn't making you happy I would put in a 318 with a 727 and see what you get, then if its not quite right, change up the rear end to get there. Happy motoring!

 

Man I never thought I would get this much response from people. Thank you all for the great advice. Let me give some more info. I live in the backwoods swamp land of Louisiana. So I really don't have to do a lot of interstate driving. Now i am not 100 percent sure if it is fluid drive. It does have the torque converter,but it does not have any wires vacuum lines or anything of that sort going to the trans. But it does say fluid drive on the back bumper. Now this is the first time I have done a build of this sort. I normally build camaro trans am,and hop them up for power. When I got the car i was just thinking of gutting it out and doing a crazy build. But the more i worked on it looked in to it,and the history being that it is a after ww2 car that really made a difference. I love the look of the Flathead, it is a very different thing to see.
For another question. The 80 to 90 psi compression I have,is this enough to make the motor run good enough to drive like normal. This is why I question the rebuild due to the low compression.
Another thing my buddy said he can build a turbo set up for the Flathead. Any thoughts on this. Thank you all.

 

It might be worth your time to jump over to the P15-D24 forum. Those guys can probably answer any question you can possibly think of about your car/engine/transmission. They might not approve of putting a SBC in your car, but they are very forgiving, and a good bunch of gearheads.

 

Seriously, fire this thing up. Fuck the compression test. Put some fuel and spark to it and spend a couple hours one afternoon getting it to yard drive even off of a temporary gas tank and drive it. Then you'll know what to do. Rip it apart then your balls deep in this thing for what? Because maybe the engine might be tired?
That car is not really A-1 hot rod or custom material but is cool as an old car so maybe just enjoy it as a bomber.

 

You did a re-ring and you have 70 lbs per cyl...did you grind and reseat the valves? I have put lots of miles on Mopar flatheads and they tend to go two or three valve jobs to a ring job. There is an easy, old school method to figure it out.

First, take an old spark plug and break off the ceramic end, cleaning it all out, just leaving the metal shell (the base) with a hole all the way through it. Next, take a metal valve stem and either braze or epoxy it into the base. Once this is cooled (or cured if you use epoxy), you are ready to use your "new tool."

Remove your spark plugs. Turn the engine over until you get compression on a cylinder. Screw in your new tool, then put compressed air in the cylinder. If you hear air leaking out at the carburetor, it's your intake valves. If you hear it at the exhaust, it is your exhaust valves. If you hear it at the tube where you add your motor oil, its your rings (or cylinder wear). Do this for each cylinder. This should help you figure out why you only have 70 lbs of pressure on a re-ring job.

If the car is a Fluid Drive, it has a 3 spd trans and the fluid drive coupler (but no electronics, solenoids, etc). This set up has a long input shaft. I have not seen any modern trans conversions for it. If it is a Gyromatic, it has the odd, semi-automatic trans with a fluid drive coupler and associated electronics - big difference.

I have the Fluid Drive setup in my '53 Dodge truck and I like it. It is different and it has been as reliable as a conventional setup. You just have to have a good emergency brake (or get ready to chase it down hills).