If a 392 Hemi was to find it's way into a 6cyl '60 Plymouth, must I change the torsion bars to suit? Is it dangerous not to? How big of a job is it and are there any pitfalls? Will that engine fit? Will I be able to wipe the smile of my face if I get it done? Ideas welcome.
I was under the impression that all the torsion bars were the same except station wagon, and that you'd have to crank up the torsion on the bars to make up the difference in weight, but I could be totally wrong there so don't listen to me. Sounds awesome though.
I don't know one way or the other, but I doubt they are all the same. Different weight cars need different spring rates. Adjusting ride height to compensate for weight doesn't change the spring rate of the bar.
what kind of Plymouth? and you might need to change the torsion bars, there are different ones for different engines, but you may like the way it rides with the 6cyl bars and a hemi, but then again it may bottom out a lot, put it all together and see.
I'm not sure on a 60 but 64's have different diameter TB for 6cly, V8 small and big block. Alot of drag racers used the 6cly TB to get the weight transfer up faster with the weaker bars. The car with the 392 hemi and 6cly bars might be a handful for street driving but great at the drag strip.
50 year old Tbars may need changed out anyway. If they crack well..that's never good. Will they handle it probably. Tbars are not hard at all to change out and they really make it easy to change ride height. But the lower you go the bigger diameter tbar you will need to keep them from bottoming out. I would recommend bigger diameter bars. To change out Tbars, you basically want to jack the car up, maybe take some weight off maybe leave the tire on the ground a little. Then back off the adjuster that is on the lower control arm. Then there is a clip on the end closer to the tranny area that needs to be removed. Once you have the weight off they may actually wiggle out. One thing you do not want to do is nick a tbar when removing it if you want to re-use it. There is some good info out there that will give you some helpful hints.
I just dropped a 331 into my '60 Savoy. It was a /6. Haven't driven it but once so far, but it seems OK around town.
The 331 shoe horns in nicely! Not sure how much room you'll have for the air cleaner with the raised deck engine, depending on if you want to cut the hood or not. You'll need the HH OEM up angle oil filter adapter. Think I had to use the ex mans that point @ the pan.
PST (Performance Suspension Technologies) makes new torsion bars for 70's mopars not sure about 57-64 but give em a call they may be able to help you out.
Was the original engine a Chinese 6 or a flathead in 1960? If it was a flathead I'm wondering if the hemi is really that much heavier.
Thanks for your thoughts guys... it's a tidy car and I want it to look like it should be in there if I can, so I'd better do my homework cos I don't want to cut the hood. Also there is no mid chassis, so a new g/box x member will be required. It has the original cast iron t/flite and I want to use the push button function. Please keep those thoughts coming. Can those T/Bars actually snap?
The '60 cars used the same T-bar for all large cars. But they never had hemi's so the same pitfalls that hamper any engine swap apply.
The 392 will be a lot heavier, the original motor would have been around 450 to maybe 500lbs. The 392 is in the 700's, so it will make the car feel softer. You should relocate the battery to the trunk to help compensate for that. It would also be stupid easy to transplant an RB motor, but you would need the big block bellhousing and the Big Block has to have the 8 bolt crank flange. If your torqueflight is air cooled only you will need to add a tranny cooler and beef up the internals. I put an air cooled iron TF behind a 392 in my 58 new yorker and killed in inside of a year. It sucked. why do you need to add a mid frame? Its a unibody car, and that seems pretty overkill. Yes the bars can snap, but its rare especially now. Back when this suspension design first came out in 57 there were issues.
The deck is higher, but the 392 intake is slightly squished for hood clearance on the 57-8 cars. IF the carbs linkage clears the intake w/o a spacer that'll help, if not the thin squeeze plate would be the way to go. The 3 speed tranny from a 318 A Poly up to '61 will bolt up.
Arominus...I didn't mean a whole subframe, just a new crossmember 'cause the existing one will likely not work as the current g/box is a 904. The current box in back of the 392 is air cooled but you cant run a trans cooler cos there are no fittings to hook it up to. I wanted to get it flushed and the techs could find nowhere to plug in and out of .....mind you I could be wrong not being familiar with the bigger T/flites. As for RB's well, I could get my hands on one ..but I've got this hemi Moving the battery...good thinking...... George...the intake does seem quite low...this thing has a 2/4bbl setup and it's quite low profile with slim airfilters. Linkage is already set up and works well. Good to know that the Poly g/box will work....and may use existing mount.....I know where there are a couple of them. Which flexplate and T/converter would you use for this swap?.....any other tricks?
Imperial Services makes an adaptor to use the push buttons with a modern 727 & you'd need an adaptor for the tranny. Gary "73RR" here makes a good one. On my tranny crossover I cut off the piece that has the coil spring mount on it & added 2 ears that go either side of the 70s droop loop tranny mount. As far as looking stock my 331 looks good! You don't have to cut the firewall or inner fenders. You will lose your heater core & will have to make a filler plate for the big hole. Poly tranny: the early poly tranny (vs 62 & up) have 8 studs through the crank flange held on by nuts. You'll probably have to use the torque converter that comes with the tranny if you go that way. If you go modern tranny you run a 1/2-20 tap through the holes in the crank flange & use a 426 hemi flex plate, your choice of T/Cs.
Usually the only time the torsion bar snap is when dirt builds up in the cups and they cannot move freely. I would adjust the bolts a couple cranks and forget about it. No body makes new bars for these cars that I know of. They can be a real bugger to remove if rust and old built-up dirt is involved.
The 6 cyl cars of the '57-64 era have smaller diameter torsion bars in almost every model. The 8 cyl cars had a slightly larger diameter bar. There were also Heavy Duty bars in some station wagons. The only cars standard with HD torsion bars were the Chrysler 300s of the era but Chrysler and DeSoto long wheelbase cars have longer torsion bars as well. Since your car was a 6 cyl. originally, I would SERIOUSLY recommend you go out and get a pair of 8 cyl torsion bars to hold up that 392. You aren't going to find any NOS bars and no one has reproduced bars for this era so far. Also if your 6 cyl. car did not have a front anti-sway bar, get that at a junk yard also. Take your calipers along when shopping. Measure your 6 cyl torsion bar and (if you had one) sway bar before you go. Buy anything heavier that is the same length as your t-bar. Be sure to keep the LEFT bar on the LEFT and the RIGHT bar on the RIGHT. They can NOT be interchanged side to side but it does not make any difference which end is forward or back. The idea that old torsion bars will break is a total MYTH. Do old coil springs break? NO. Why would old torsion bars break??? They do the same job.
Guess I have to be the myth buster on this one, since I have a collection of both broken old torsion bars and old broken coil springs. I have some broken leaf springs as well, just in case you missed those. Torsion bars, coil springs, and leaf springs are all springs and are subject to break at any time. I had a torsion bar break on a car while it was just parked and siting. No one was even within 20 feet of it. For the record, if your t bars have been there since 1960, they will probably be a pita to change. Start cleaning out the rear sockets and lubing up both ends every day for a few weeks before your ready to think about changing them. Good luck. Gene
You should definitely change the torsion bars. Ma mopar undersprung pretty much every torsion bar car that ever left the factory, even if you planned on keeping the /6 you'd benefit from larger torsion bars. Slant 6 bars in a car with a 392 will mean you'll be bottoming out the suspension if you look at it funny. While not the same, I TRIPLED the torsion bar spring rate on my OT 70's mopar, and it still doesn't ride rough, improved the handling a ton. But you can get aftermarket bars for those years, so that's an option. For your car, with no real aftermarket options, you should at least upgrade to V8 bars, HD or station wagon bars would be better. And torsion bars will explode. And come straight through the floor if they do . The biggest issue with the torsion bars exploding is damage, gouges in the bars can lead to fractures down the road. So, if you gouge up the bars during the removal process (a very real possibility if they're stuck in there), don't use them again. Ever.
Because you haven't seen a torsion bar or coil spring break doesn't mean it can or doesn't happen. You asked why a torsion bar would break break. The answer is fatigue. Steel is subject to fatigue failure. It's a function of how much you flex it, and how many times you do it. All springs are not made the same. There are a variety of manufacturing and processing variations that effect how durable a spring is. As with most things, better equals more expensive. Some applications and suspension designs are inherently harder on the spring than others. On production cars the most economical spring that will do the job reliably is what is used. Although there are both bending and torsional forces in coil springs, they are essentially a torsion bar that is wound into a coil.
Thanks so much for the input guys...I'm starting to get the picture..it's do able but homework on the torsion bars will be a must, just for starters. It's RHD as well, so the steering box may foul something. I guess the first thing to do is take a lot of measurements.. Will bars from late '50's cars fit?..or am I looking specifically at '60..'61 cars? Unfortunately our wrecking yards are full of japanese cars....not an American car in sight, so finding the right bars could well be a mission. Here's a pic of the hopeful recipient.
Looks familiar, this car posted @ the Forwardlook? Forwordlook would be a good place to ask if other yrs bars interchang. Might be some come up for sale there. The engine clears the steering box on LHD, so if RHD version is proportionaly the same it'll clear, but not by much!
You can avoid damaging the T-bars at removal if you get everything detached from the lower a-arm and then pop the nut off the a-arm pivot. Then pull the c-clip and clean the hex out on the anchor and spray it with penetrating oil. Then get a big pipe in between the a-arm and the engine crossmember and push it back. Im looking into the t-bar interchangeability, the cars changed completely in 60 so i'm not so sure they will interchange with the 57-59 cars. 57-59 had 2 different t-bar lengths on top of that, one for the plymouth/dodge/desoto firesweep, and the longer ones for the big desotos/chryslers/imperials.
Forgot to mention...you won't have room for a power brake booster. I used a manual dual pot M/C from a later 60s Mopar. You'll have to unbolt the M/C to get the valve cover off. Probably isn't any worse than having the Slant leaning over tword your M/C, steering box & column!
I paid Steve Charette of Imperial Services for a push button conversion (late 727 to 1964 push button shifter), no delivery in over 3 years!!! I don't live in MI, so he took the money and ran! Every time I called he said 2 more weeks. Since last April 2011 there is no way to get a hold of a human, just leave a message and they never call back. $500 and my original push button shifter sent in - lost to Imperial Services!!! I have gone to the trouble to get another pushbutton shifter off of ebay, and I think I can do the conversion myself. I am going to fab up my own cables from Pegasus (see the push-pull cable selection at the bottom of this page https://www.pegasusautoracing.com/2011/053.pdf) If your interested let me know, and I will let you know what I have done so far, for FREE.
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