...."classic" hemi for a "classic" street rod.....very, very cool!!

It's one of those combos you will "never forget seeing"...!!!

All the rest are just some variation of the same thing, over and over and over..lol!

 

Sub, it was originally a 383 4 speed car, but had a built 440 in it when I got it. Car was red with a white and black bench seat interior, and had 63,000 original miles on it. I sold it for 3k in 1994....guy bought it for his 16 year old son, who supposedly wrecked it. it would bring ten times that amount today. It was a fast, good running/riding/handling car, but with the typical Mopar tininess that made my GTO's seem like bank vaults by comparison.

 

The piece above the axle is a panhard rod. It keeps the axle centered. It is bolted to a tab on the frame crossmember to the right, and the axle to the left (out of the photo frame).



The right side axle mount saddle is welded to the axle, and the trailing arm attachment is made with u-bolts that hard-bolt everything together.

The left side axle looks like it has a similar welded saddle pad and u-bolted connection to the trailing arm, with the axle end mount for the panhard rod behind the axle.



It is easier to see in this left side photo that both sides of the axle are welded and bolted the same way.

The entire rear suspension acts like a rigid swing arm. Wheel movement on one side moves both wheels up & down. The wheel travel action is stiffer than a more traditional two leaf spring system because this axle is fixed and cannot allow the axle to tilt when leaned into a turn or reacting to a bump. The effect is like having a massive axle tube diameter rear anti-sway bar. This is OK for a drag car, but makes a rough ride on the street.

Removing leaf springs will soften the straight line plush feel of the suspension with more squat on acceleration. What it will not change is the stiff ride in uneven bumps or turns.

The other concern, without too much detail, is the instant center of the suspension has been moved back, compared to the stock suspension, by locating the axle center line above the trailing arms. The trailing arms look level, but the imaginary line from the axle center line to the forward mount of the trailing arm is raked forward (or titled down). Without launching the car it is difficult to feel how it works in a launch. I expect the short IC will jack or raise the rear of the car on launch, more than the stock suspension that squats due to an extremely long instant center. If it lifts the car and does not lose traction spinning tires it is balance (the poor designs spin tires for show but do not launch well for acceleration).

If you keep the live axle and want the ride to improve a little, one of the two axle to trailing arm mounts need to float or be hinged to allow axle housing rotation independent from the other ends of the axle. On traditional leaf spring cars with links or ladder bars they float one or both axle housing mounts in a cage to allow rotation.



You will need to float only one axle side to allow the housing to twist above the trailing arm.

A traditional leaf spring with ladder bars has float (axle housing rotation) cages on both springs. This link may help: http://www.jalopyjournal.com/forum/t...ousing.821957/

If the ride is OK for your use, don't mess with it. If you want a better turning and handling ride with comfort, a stock suspension will probably cost less than floating the axle above one trailing arm (unless you do the work yourself).

The early hemi's were fun. I worked on stock 318 and 361 hemi's back in the day, and helped on a number of 392 race variants. Tough engines. IIRC, they could crack between the cam and crank webbing if pushed too hard (1000hp or more). Heads would crack on alcohol. They made fun boat motors, and then boat anchor moorings as the BBC displaced their use.

Nice car.

 

63 340HP
You are right on it. Thanks. So that's exactly what they built. A couple times I've tried to spin the tires from a start that feeling of the rear lifting up is interesting. Now I see what you are describing. It's a weird feeling and surprising, to me, takes a lot of power to break the tires loose.

The car needs a little detailing, I want to add the little rear lip spoiler like my 1st vette, and I don't want a vette like everyone else's. This winter it will get that done with a repaint.

This 392 is suppose to be either a350 or 380 HP. It looks like the tach has the original redline from a 327/300 HP, 5500 RPM. Is that a reasonable redline for this engine also?

Thanks for your help.
Kent

 

Wx permitting I love to get out and go for a drive, even short and stop at the American Legion. Issues I want to address. The rear, obviously is very stiff. That needs to be addressed. Any suggestions?? If I get on the power it feels like the rear winds up and raises up. What is that all about? I can say this car will be a driver on descent days and maybe a run at the drags since I've never tried that. But soften the rear suspension and what is that wind up and lift feeling I need to understand. Compared to my Porsche I'd say this is probably the 392/350hp Hemi. It doesn't feel as strong as my old 365/327 or as quick as my Porsche (9:1 pwr to weight). That's fine for a driver that draws attention and questions. Any help in this area would be appreciated.

Kent

 

340 Hp gave you a lot of good information to chew on!

On the rise, the only thing to ask about is the tire growth, if any or the tire air pressures and such!

And our Porsches rip apart new Corvettes, and that is why we mod the crap out of our Corvettes in the family! Can't have my families members cars embarrassing the Corvette side of the family!

A 1973 RS Duck with 210hp stock is a match for most C2/C3 Corvettes! You are lighter and have more than 210hp! Was you old solid lifter Vette wearing headers?

 

It doesn't feel as quick as your old 327 cause it's heavier and 340 HP spelled it out pretty good for you, he's got a good grasp of suspension basics. Read it again.

 

kolson911
I'm rebuilding a 392 Hemi. It's not going in my Corvette but maybe a Gasser I have in the works. Let me know if you need any help on the Hemi. They are actually a very easy engine to work on. Only problem is the cost of parts.

 

I assume you are saying, " If I get on the power it feels like the rear winds up and raises up. What is that all about?" Meaning the rear of the of the entire car, not the rear axle only raising.

The reason the rear of the car is rising is because the Instant center is working. Try looking at it this way. If the rear half of the car weighs 1500 lbs, and the rear of the car is rising on acceleration, that means the rear is not putting a down force of 1500 lbs any more, but rather a much higher down force of 2000/4000 lbs or more of down force, depending on how effective it is. Very good in drag racing. That is why My car pulls the wheels every run in first and second.

Factory rear suspensions usually go for a more neutral instant center so the ride is better. They usually squat upon deceleration, Thereby taking the 1500 lbs rear weight down force and reducing it to 1000/500 lbs and a loss of traction. Not good for fast starts off the line.

With that rear suspension in your car, It had to be done along time ago, way before Instant centers were known. They did a good job assuming the rear raised on launch.

Hard springs do not relate equally to hard rides although, with leaf springs, a need for a certain stiffness is to maintain that link. If I were you I would install a 4-link and coil overs, as said earlier. Jim

 

My old vet was stock except the engine. It was originally a 300 hp I rebuilt to a 365 hp with Hooker headers.

My new vette is not stock, dah! I'd like to get a friend to take a picture of me accelerating so I could see what the rear end looks like. The raising feeling is weird but what ever it is doing is really helping the traction because it feels like I'd need over 4000 rpm to break the tires loose

Kent

 

kinda 'apples and oranges' in what i'm about to say...

do you remember the old Ramchargers and other mopars of similar ilk, they rose up in the rear instead of squatting when launching (and that with leaf springs)... if anyone should have known about weight distribution/transfer, they would have.

you're in good company..

Bill

 

Ok now I'm at a loss. Finished tinker with the car yesterday and today dry and sunny, so another test run.

Standing start, reved up to 4000rpm, dropped the clutch. Some clutch slipping, then it feels like the rear end winds up, the rear end raises and the clutch catches. It felt like the tires broke lose but only spun maybe one revolution !!!

So I remember something called a torque link back in the day. Is that something that would stop the rear axle from winding up???

When you look at the pictures on this link of my rear suspension I don't see anything that would stop the rear from winding up????????

 

Did you read post 70? that's a smart man there telling you about your car, little clutch slip is good and tire spin is good, one revolution maybe and it took off that's great and you want your clutch to give a little when dumping the clutch.

jp

 

So your saying that's what it is designed to do. Again I know nothing about drag racing.

 

​​​​​​​The race mopars used what is probably the best stock leaf drag race system for a solid axle suspension. They used asymmetric length and stiffness leafs with a pinion snubber. The stiff and short leaf construction ahead of the axle worked like a rigid three link with the pinion snubber working as the third center upper link. The soft long leaf construction behind the axle worked like a 1/4 elliptic leaf for isolated spring effect. The combination provided minimal leaf spring wrap and axle rotation, with the added pinion snubber stopping axle rotation and effectively lengthening the instant center for a better launch (a launch tuned to produce minimal rear lift and minimal front lift for a good tire plant and good aero profile recovery down the track).

I worked on a Dart with an 8 3/4 posi like the OP axle. We had it launching very well on 10.5x30 slicks and 4.10 gears with some excessive slip (maybe five tire turns on launch). The owner found a magnesium 3rd member drop-out with a spool with 4.88 gears and we fitted it up with 14x31 slicks. The first day out, all went well with much more consistent times and maybe a 3/4 rotation launch (a mid-11 second car at @118 mph). We returned the next day for brackets and colder weather with better air. The better power had us jacking the rear end and a good plant, but spinning at 20 feet. The front antisway bar was removed and we installed a shorter pinion snubber, to get more weight transfer and move the instant center to reduce the jacking. The intent was to try tire slip out of the hole rather than 20 feet out. The car launched almost level, with maybe a 1/4 rotation slip, and broke the pinion out of the magnesium 3rd member casting. The mopars system could launch well.

I the Hemi only spins a little on launch, and settles well, then a change is up to your ride preference. Changing only springs, coilovers for the leaf, will not change the suspension geometry. A four link can change geometry, with adjustable links, an option the fixed trailing arms do not have.

I is likely the rear suspension jacking is limited by the trailing arms contacting the bottom of the mounting slots in the frame. Place the frame on jack stands and you should be able to observe what is limiting the lift travel. The arm travel bind and shock length are the two most obvious places to look. A small rubber puck located to cushion metal to metal shock can make a big difference in ride and performance. If you feel a hard slap and find tire slip mid-launch, the bind of metal to metal contact could be upsetting tire traction. The shock load at the arms can upset and release any tire sidewall tension before road speed catches up to tire rotation. This is not likely an issue unless at the strip with drag tires, but knowing the effects and cause/solutions can help reduce some of the everyday ride harshness.
​​

 

Dry today in Oregon so I needed a test drive in the Porsche but one more problem with the distributor will drag that out for another week waiting for parts.

Not a day to drive a 100hp Mini so the Vette gets the vote.

Up my test road in the foothills, back down to the main road then across the valley to the next county road and back to town to the Legion for a beer. That big block just rumbles so nice. It has been near 30 years since I've enjoyed that sound, fellows it gives me tingles. All my vehicles with their 4-6 cylinder engines just don't have it. Whether it's fast or not there is nothing that sounds like a V8. Makes you feel like you are the man!!!!!!!

KO

 

Interesting Post.... My $.02 worth would be....If the car has some unique history value I would adjust to your liking and drive the car and enjoy the surprised people who marvel at the engineering in the day.

If you plan to drag the car and like to spin the tires then after you tweek it based on the other posts that's fine also. Also if you like the ooo's and ahh's from showing the car as it is very different then your all set.

But if you want a nice driver that will give you a good Standard Corvette ride then your in the wrong ball park with the current rear set up. Your car looks very nice.

I have a 502 with a 5 speed and the stock rear 9 leaf transverse spring with 205X 70 R 15's. They are my safety valve which prevent me from twisting the frame and leaving parts on the road when I jump on it. They break lose and spin preventing me from damage

I can smoke the tires thru first gear if I want. I don't do that all the time. Remembering that all the twisting power ends up at the half shafts tires breaking lose is a good thing preventing the rear form throwing half shafts thru the floor.

Also protecting my drive line and frame from damage. My Vette is a driver and road trip car as well as doing Coffee and cars and cruise in's and the occasional get down on it.

So If you would like a good driver and back end that can handle the torque from that Hemi ...the I would suggest you dump the complete rear end set up and rebuild factory stock..9 Leaf..for the best ride....or 7 Leaf for handling ..sacrificing some of the smooth ride.

But If you are into the drag and front end lift and being different then just work out the bugs in what you have.

I would also say again that I would try and find out who built the car and it's history as it might be something worth keeping and showing.

Again..Just My $.02 worth. It's your Corvette... Do what you feel is what your want.

 

I don't know how "bad" that car rides but I think it's more reminiscent of the era than many of the 60's cars on here and other Chevelle, Mustang, Pontiac etc. forums that are all over the internet.

We all remember cars that were notably different or notorious... Those were the cars that were legendary...and some were pretty rudimentary by today's standards. Sound's like someone had a suspension that would have been very unusual for its day...and may have given it an edge among the local Saturday nite street drags.

You may have one of those local street legends in your possession right now! It just doesn't get cooler than that!!

I'd love to have the car the way it is...if I could stand it at all....most street races were won (or lost) in the first 50 feet back in the day.

As you may have gussed ... I "am" old school..100%. You had to live it...but any Hemi in a Corvette would have been "scary competion" in most of our minds back then.

Not something you would generally go huntin' for late Saturday nite.

 

I'm with Stan, and like what you're doing with the car: doing just enough tinkering to make it livable on the street, but keeping its history and unique pedigree intact. It's a special car, and with the Hemi, as visceral as it gets!! A little tuning for a slightly softer rear suspension and away you go.

 

Prior to 63 they were all solid axles I keep thinking. However I think the fellow that installed it all has passed away so no help there. The last owner is still down in the Bay area so I may call him back to at least get the fellow's name who built the car, he may have a reputation in the drag racing ranks.

Not that much interested in drag racing but I'll try it once just to say I have. Might find some older gents who would recognize what's under this old girl.