Technical new in Dodge Flathead 6 - any improvement available?

That coupe is beautiful!!
Even as is, it should be a good driver.
I have a '48 plymouth, with 217 engine. It has a split manifold with dual exhaust, running through short Brockman Mellowtone steel packs, a O'Brian Truckers tall air cleaner, and timing is advanced. It drives well in town traffic, runs 70+ with ease (3.9 rear gears).
It also sounds great.
It isn't a race car, but I am not holding anyone up.
I have been building a performance engine to swap in down the road.
Mopar made constant improvements on these engines through the '50s, ended up with 8-1 cr, over 130hp. Power curve is very flat.
They may be slow by today's standards but make more hp/CI than the beloved flathead ford.

First you need to figure out if you have a 217 or 230. I can see a tag on the side of your engine, it may indicate a replacement was installed. Look at your engine number here:
https://t137.com/registry/help/otherengines/otherengines.php
You also need to figure out what transmission you have: if fluid drive bellhouse will be gigantic, standard clutch will be average sized.

For mild, mostly stock performance improvements, dual exhaust is a big help. Make sure your vacuum advance is not leaking, everything inside the distributor is working well, and all your ignition components are in great shape. Bump base timing up as much as the fuel you run will allow without pre-ignition.
You could run a riser under the carb.
A head from a '53-54 217, milled .050 would give you a 75-77cc chamber, around 7.8-1 cr, but you would need to plug the internal water bypass hole at the front of the head.

Improving quench is good, but hard to do without taking the bock on a trip to the machine shop. Most available head gaskets are around .060 thick. Pistons usually sit .010-.020 below deck. Aftermarket Pistons have a compression height that is .020 shorter than factory.

 

Gentlemen,
it is overwhelming to read how you go to the trouble of giving all your experience and know-how to a Dodge Flathead 6 newcomer here. I've been involved with American cars for 35 years, but this forum puts everything I've seen in the shade. Even that I took such a nice car to Europe is no problem for anyone. However, they are all very helpful.

I would like to sincerely thank all of you for that
Joe

 

If it hadn't been mention I think it is Clifford that makes hop up parts for these.

 

Dunno, I haven't monkeyed with them since the 50's.
Talk to Earl Edgerton of "Edgy Cams" in Santa Rosa.
He knows all.

 

GT, thanks for myself and others. We try to get along here and if you have a cool old car and want to make it better and faster, this is THE place for it. Some sites have more unique specific knowledge, but the people here along with respectful mods have not been bested in my experience.

 

Hey, GTfb;
If you choose to explore the supercharging route, as mentioned by Rusty & myself, here is something I wrote on another thread on McCullough & early Paxtons:
Jon & Mike(son) Meyer are good folks, knowledgeable w/paxton blown engines. Can correctly rebuild the paxton if needed. *Won't* steer you wrong or lie to you. Or rip you off. If you need contact info, PM me. Known these guys for years. Just talked to them Fri & Sat at the South Bend Studie meet. I would, & do, trust what they say. .
Oh, & btw;, the boost from the McCullough is dependent on it's condition, maybe if modified(?), engine size, rpm, headport flow, etc. On a 289 size mill, usually see ~ 3psi(+/-) inside the manifold under carb(s), 5-7 at the blower outlet. Still results in impressive results.
Marcus...
Someone else posted their contact: https://www.myersstudebakerparts.com/
If either of the Meyers don't have a blower or a core(& they usually do), an acquaintance has a few. I could inquire if you wish. I'm not going to broker it, but I'll help if it's wanted. In mid-Sept, these guys will all be together, so a handoff might be arranged. Meyers might have enough parts to make a "kit" to work, idk(his primary focus is Studes - although Stude did have 2 sizes of flat-6's these could fit, it wasn't done that often). I'd be looking for a universal version for a flat-6, Kaiser used a lot of them on their Continental flat-6's. Might be a close fit, idk.

Earlier I wrote: "The blowers would get you ~ 4-5psi, = ~ 40% increase in actual useable hp/torque; & at the same oem rpm range, keeping engine stress to a minimum." . In the past, engines kept within the ~OEM rpm limits didn't need modifying, & kept the drivability of the orig design. Just lots more fun w/the blower. As Rusty mentioned, this assumes that the engine is in good shape - which *all* the old book/literature warns about. You mentioned some of your other street terrors, so this'll just be more fun, & if the black car is yours, very un-assuming, & also very nice. I think you're going to need some professional-quality smile-remover for your face...
.
Marcus...

 

Lots of really good info on here! I hope to one day have one of these cars. I’ll keep this thread marked in the meantime. I’m a Chrysler guy through and through and I like seeing some speed parts for these old work horses. Ford guys seem to have the most to pick from for vintage speed parts but I’m glad to see there are some offerings for us pentastar guys.

 

Well fitting a supercharger and certainly a turbo would mean a battle with the German authorities because they have stricter inspections and type approvals for anything not period correct (ah the joys of living in Europe).

From my dim and distant recollection I believe you could with all the sensible mods mentioned above get a reliable, genuine 130 hp from a 218 or 140 from the 230. This is more than enough for sufficient acceleration from a stop and cruising at 100 km/H on a German Bundesstraße all day long, which is what the OP wants (120-130 Km/H on the Autobahn should be possible too but only with an overdrive, which means mods again).

 

Oh tell me about it lol. I just had a few rear light screws and gaskets sent to Austria, the shipping (DHL) and customs duty were 3 times higher than what I paid for the items. USPS used to do surface which was a lot cheaper but sadly no more...