PT81PlymouthPickup

Welcome Mertz! Great to hear there's another Plymouth truck person on here. Not too many 39-47 Dodge guys, let alone 39-41 Plymouth fellas / (Being politically correct) and ladies. I think I speak for most of us? We like pictures! Not to meaning to UN-inspire, I've been working on my truck for 41 years now, and it's still not finished. lols. This is a great forum! Steve ☺️??

Just another thought! You likely have a 4.11? You may be able to find a 3.90 ratio original style pumpkin differential. I think that's the highest ratio they made for these rears? That with some taller tires 650-16 or 700-16 will probably do the trick for higher speed / lower rpms? This way, you don't have to change out the housing and associated changes needed to do that.

Mopar alternator! Frank's posts reminds us we should be committed to Chrysler Corp. Or in my case, perhaps, committed to a mental institution? ???

Hey Frank! Does this mean Borg Warner T5s are sacrilegious in our Mopars? ?

The Non World Class Borg Warner T5 transmissions used in 1980s Chevy S-10 pickups are a popular swap for our trucks and many other vintage vehicles. The gear ratios work well for our trucks. There's lots of info on this popular swap. I'm not sure how available T5s are now? When I did my swap, I found one in fair condition for $200. It did need a couple of gears and synchros. There was also an issue with the input shaft which I had to change. Can't remember exactly why now? I think it was the length? Time I was done with it, had $800 into it and I did all the work. Anyhow, I'm a machinist by trade and a shade tree mechanic by hobby. What I'm alluding to, is your skill level, free time, and resolve will determine how difficult this project would be. If you love doing this stuff, and have plenty of time it will be fun. If not, you might end up never driving your truck again. Are you're 4 speed, pressure plate and clutch are working properly? Are you sure your 4 speed is unsynchronized? Perhaps someone on here can verify? I must admit, I don't miss gear grinding, but I also know if everything is working properly and with some practice you can shift the old boxes smoothly. An old friend (retired mechanic) of mine took my truck for a spin when it still had the unsynchronized box and he shifted it perfectly without using the clutch at all after it was moving? I felt like an idiot! Lols!

Hey! Nice looking truck! I installed a Borg Warner T5 behind the original flathead and a Dana 35 posi differential out of a Jeep Cherokee 3.54 ratio in my 39 Plymouth. I'm happy with it, but took a lot more time than I figured with some challenges along the way. If you just swap out for a newer trans and differential, and want to do it right, you will have to cut a small section from the cross-member, weld new spring perches, adapt emergency brake lever, make a new floorboard, custom length emergency brake cables, make a new driveshaft, custom length speedometer cable, and a bunch of other stuff I can't remember. If I were to do it again I would select a 3.73 ratio. Unless you increase the horsepower, you will be shifting too much in moderate hilly areas with a 3.54. If you're thinking a v8 swap, you're really talking major adaptation and probably not a great idea without also upgrading suspension, steering, brakes, etc. Just my opinion, keep it fairly original. A 3.73 rear with the flatty will move you along just fine. Good rubber and brakes of course. Even though I don't recommend it, if you're thinking the street rod route, lots of information on the H.A.M.B. www.jalopyjournal.com/forum

Anyone know where to get a couple new or used hub cap clips for the original artillery style wheels pictured below? I can't seem to find any that look like these?

Update on 1939-47 truck wheels: First, thanks for all the input! After considerable confusion and pondering, I just ordered two 16 x 7 Vintage style wheels from the Wheelsmith. They look very much like my original 16 x 4" wheels. I ordered the minimum backspacing of 3-1/2". When compared to my original wheels, will increase the wheel width inwards by 3/8" and outwards by 2-7/16". This will allow me to run wider tires and fill in some of that big gap in the rear fenders. I'm thinking of running 225/75R16s on them because they match the outside diameter of the 650-16 (29.3") and are 3"or more wider than the original tires. Nothing radical, but I'm hoping the combination of offset and width will give a better cool factor to the back of my truck. The front wheels are going to be a more difficult task. I want to keep the narrow wheels on the front axle due to easier steering and no rubbing issues. I am going with all radial tires which very much narrows the tire options. Having converted to disc brakes, that already pushed the spindles outward a small amount. One of the reasons I chose Scarebird disc conversion was it had the least amount of outward offset than any of the other kits available. I have not been able to find any 16" vintage style wheels that have the same backspacing as the original wheels. The closest ones I've found would push the wheel further outwards. I really don't want to increase the scrub radius any more. So, it brings me back to maybe just mounting radial tires on my old front rims, which I can do with some vintage radial tires that Coker offers. I however really don't want to mess with tubes. Here's something I was surprised to learn during my research. Mopar was perhaps the first to produce safety beads on rims? That got me thinking to take a closer look at mine. Sure enough! One of my wheels has them. The others do not. They are all 4" wide wheels and measure exactly the same. It's a little difficult to see in the photos below, but if you look closely you can see the indentation in the first photo. I'm thinking I might find a one or two of these rims in good shape that have safety beads and mount up the front tires without tubes? Wishful thinking? I'm wondering what year they added the safety beads?

Your 51 truck is Sweet! Any photos of your 42? Maybe the previous owner went to the smaller rims to have more options of tire sizes? Are the wheels on your 42 the 4-1/2" wide OEM Mopar wheels or aftermarket? I've read where running modern radials on our antique wheels is not always safe due to wheel design and rim width. Radial tires exert different forces on the rims than bias ply. I believe my wheel center section is riveted to the rim. Seems like a potential for leaks? Some have mounted modern radials without tubes and have not had any issues. Some companies like Coker sell period sized radial tires that require tubes? I would like to eliminate the tubes. There are companies selling vintage looking wheels made for tubeless radials, but as discussed earlier don't have the clips for our oem hub caps. Some here have suggested having my wheels customized, but I'd rather stay away from that route. My head's hurting! Lols! I'm also concerned if I mount wider radial tires on the front axle it may make the truck steer a lot harder when at very low speeds such as parking? I'm currently running 6.50-16 which measure 29.5" dia. and about 7" wide. Even with these skinny tires it turns a bit hard when parking.

I think I got some bad web information. I just measured my tires with a tape measure; The 6.50-16 tires measure 29.5 diameter inflated and a 215/85/R16 I had laying around measures 30.4 not inflated. Not sure how much difference inflation would make?

Ed, were you referring to 215/85/R16 tires on your truck? Is yours a half ton pickup? The 215/85/R16 has a 30.4" diameter. My original 6.50-16 tires are 26.4" diameter. I'm thinking these may not fit my front fender-wells?

Been working on other projects, but beginning to think about wheel / tire replacement again. My old bias ply tires have considerable cracking and I'm tired of fighting the steering when the bias ply tires follow imperfections in the road. Anyhow, I really would like to keep the wheels at 16" dia. I just think they look better (eye appeal). I believe the rims are only 4 - 4-1/2" wide? Sounds like a few of you have been able to run modern radial tires which are designed for wider rims without tubes. I'm a little skeptical if that's safe? Getting back to eye appeal; The stock sized front rims and tires fill the front wheel wells nicely, but on the rear they look really wimpy in those huge openings. To achieve the look I would like, I would have to have wider wheels and tires for the rear only. I know lots of street rodder's do this, but I'm wondering how that might affect the handling on the 39-47 trucks? I'm fairly certain if I had slightly wider (6-7") 16" rims made to fill the rear fender openings better, that same size would likely rub the fenders on the front axle. Seems like nothing is ever simple with my Mopar truck? Well, usually caused by me changing things. Any opinions on running wider rims and tires on a rear axle and narrower ones on the front?

I've seen old brake hoses do weird things. They can collapse on the inside and hold pressure and release when the hose is moved by moving the steering. Rare, but plausible?

I've been using Mobil 1 synthetic 10w-30 in my flathead. It's expensive and probably overkill, but having once worked for Mobil Oil Research and Development labs and witnessing engineering tests they did on this product, I was sold. I'm not sure about all synthetics, but one of the things that sold me was Mobil 1 will withstand extreme heat compared to all conventional oils. I figure it's cheap insurance in case the cooling system were to fail.

Pete, did you rebuild or know the history of your engines? I'm thinking you would have to compare two fresh engines, one with filter and one without to get a good comparison? If one of your engines had less maintenance in it's past, it's likely the oil would get dirtier faster due to deposits in the crankcase. The fella I know with the Ford flat head (he rebuilt) without oil filter stays very clean. He does drive the truck routinely and changes oil religiously at 3000 miles. If the sludge you removed from your 38 truck was in an engine that you have had since it was fresh, that would be a good argument for keeping filters in our vehicles.

I know a couple guys running flat-heads (one being a Ford V8) without any oil filters at all. They have been running this way for many years without issue. My friend with the ford has over 150,000 miles. Now, they do keep up on oil changes, but makes one wonder how effective our partial flow filters are? On the other hand, I believe Chrysler included them on many of their vehicles and I doubt they would have done so if they were ineffective? I'm thinking the modern oils having chemicals to keep contaminants in suspension it might be better to have one? I must admit though, I've thought of removing mine, thinking it would simplify the engine bay and less places to leak. Any thoughts about not running one? Anyone on here not running one?

Yes! you are correct. It "almost" seemed sacrilegious to not put it in a WC.

While you guys were "stewing" I was wondering if mine was a sock type, so I took the lid off and it's not. This engine was military surplus and everything on it was deemed heavy duty? Perhaps by the time this engine was manufactured they no longer used the sock type? It would be good to know if there were different flow directions for different filter units?

Just in case no one believes me:

This may clear thing's up or confuse them further? Pictured below is an OEM 230 crate motor direct from Chrysler. I removed it from the crate myself. It's never been run or worked on. It was manufactured in 1967. The pressure hose coming from the galley goes to the side of the filter housing. The return line goes from the bottom of the filter housing to the return fitting near the dip stick hole. My 1939 PT81 is plumbed the same, but I did that 30 years ago. It's likely that when I made new lines, I copied what was on there. Can't say for sure now though. Alzheimer's is setting in. ?

Sweet car! You've found a great forum.

Yep! And we had to walk to and from school 10 miles up hill both ways. What's up with these kids today? Lols! I remember as a kid pumping gas in the 1960s at my dads station. He was paying me about 1.50 hr. and the gas price was about 30 cents a gallon. Geez! I'm old! ?

Hello Pablito, This is a great resource for early Mopar enthusiasts. Has been invaluable to me just about every time I work on my truck. Lots of people who are eager to help you. There's lot's of information on old posts as well. I struggle a bit with the search feature. Perhaps I haven't learned to use it correctly? I have better luck searching a topic on google for example. (OEM tires Plymouth P15 p15d24) which will list all kinds of past P15d24 threads about that topic. Pictures are a plus. Steve

Yes, I've read about several guys setting timing with vacuum gauges. Not having a vacuum pump or gauge it prevented me from trying. I've been searching for a decent hand vacuum pump with gauge. There's been several times I could have used one for checking vacuum pots and for brake work as well. I know I can get them cheap, but you guys will probably laugh at me, because I have been trying to not purchase anything made in China. It's almost impossible to find anything that isn't. Just a pet peeve of mine due to job losses over the decades. Even Snap-On Blue point is made in China. Like JBNeal, I want my "flathead pulling them hills and sound as sweet as flying across the floodplain" without supporting China to do it. Lols!

Interesting article Ken! I'm not quite that "avid" however. Lols! I'll stick to adjusting it in the vehicle. Funny, how although this stuff is not rocket science, it sure can get confusing. Well, I do confuse easily. I remember my father who was a professional mechanic his entire career (1940s-1990s) telling me before computers, and less traffic, they often set timing on the road. After making sure ignition components were set and working correctly, they would take the vehicle for a test drive and stop occasionally to rotate the distributor slightly to advance the timing until they could hear pre-detonation. Then just back it off a bit until that stopped. Perhaps I'll try that and then check it with a timing light to see where it ends up? So far, it seems like everyone reading my post agrees I should be OK at setting it at 0 degrees below 700 rpm? Although I won't be building a distributor test machine, I probably should purchase a good tachometer and a hand vacuum pump with gauge.