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Posted By: Rocket man Original leaf springs with a 350 engine - Wed Nov 06 2019 07:26 AM
I'm planning on using my original leaf springs on my 1950 3100. The driveline will be upgraded to and LT1 with a 4L60E tranny. I've replaced all of the spring bushings...nice and tight now. I don't plan on any burnouts...just something that can pass someone else on the road without getting a run for it, easily maintain interstate speed and sound nice at the same time. What unforeseen issues do you think I might encounter?
P.S. I've installed a Chevy 10 bolt with 3" lowering blocks.
Posted By: Apache1 Re: Original leaf springs with a 350 engine - Wed Nov 06 2019 12:31 PM
Do have some pics you could post and share with us....thanks.
Posted By: Volfandt Re: Original leaf springs with a 350 engine - Wed Nov 06 2019 02:18 PM
The original engine and tranny combo is heavier than the LT1/4L60E combo so weight wise you'll have no problem.
Matter of fact, the old time way folks lowered their hotrod V8 powered AD's by removing springs, sometimes down to just 2 springs but I do not recommend following those past practices, LOL.

Your straight axle frontend will work fine with that combination as long as it's tight with no play.

A major unforseen problem you'll encounter is shoe horning that LT1 in with clearance around the stock steering gear box. Theres many interesting techniques builders have used over the decades to remedy that problem, you'll have lots of reading to do on that. Going with an aftermarket power steering setup that moves the steering gearbox up towards the front of the frame is probably the best solution but be prepared to part with some $$$'s.

Another situation that comes to mind is having to remove the rear frame cross member that the OEM bellhousing mounts bolt to. It'll be in the way of your auto tranny. Again there's a few interesting techniques used from running without one (not good) to cutting the OEM and welding bracing around the tranny (good) to making up a total custom cross member (good).

It's all doable and many do it, it'll just cost you alot more $$$'s than installing a fresh 235 or 261.

Good luck
Dave
Posted By: Hotrod Lincoln Re: Original leaf springs with a 350 engine - Wed Nov 06 2019 07:56 PM
The "bellhousing" crossmember also serves to stabilize the spring perches, so don't remove it entirely. It's fairly simple to fabricate a dropped center crossmember from flat plate and square tubing that allows for automatic transmission clearance without compromising handling due to frame flex.
Jerry
Posted By: Rocket man Re: Original leaf springs with a 350 engine - Wed Nov 06 2019 08:42 PM
Boltergeist and Shop Shark...

I forgot to mention that I'll be installing an aftermarket Mustang II so previously mentioned issues hopefully I won't encounter. I have read about moving the bellhousing crossmember back to accommodate the tail shaft of the transmission and modifying the "back" crossmember to accept the driveshaft and any additional clearance issues. I understand that removing any support parts from the frame is a bad idea. I have boxed the rear of the frame from the back of the back crossmember to the support that is riveted in just past the axle hump of the frame. My main concern was torque issues on the leaf springs. As we all have grown accustomed to, we leave stop signs and such with a little more "umph" than we did 70 years ago...horsepower being the culprit. I was just concerned that the 1 3/4" wide leaf springs would hold up for how I expect to drive.
Posted By: Hotrod Lincoln Re: Original leaf springs with a 350 engine - Thu Nov 07 2019 01:03 AM
There is no way to predict the way such a badly butchered frame will respond to street driving, energetic or otherwise. Boxing the frame usually results in the formation of stress cracks and other undesirable consequences, but people persist in trying to "improve" a design that was developed over a long period of time by some very skilled engineers and performed admirably for decades.
Jerry
Posted By: 52Carl Re: Original leaf springs with a 350 engine - Thu Nov 07 2019 02:36 AM
Where did you read about "moving the bellhousing crossmember back"? It is riveted in place and will not fit further back without a lot of cutting, and then you will need to find a way to shoe horn it inside of the frame.
You can unbolt and slide the torque tube crossmember back to support the tail of the automatic transmission.
Posted By: Rocket man Re: Original leaf springs with a 350 engine - Thu Nov 07 2019 05:50 AM
52 Carl

Thanks for pointing out my wrong interpretation! You are correct...it's the torque tube crossmember.
Posted By: TUTS 59 Re: Original leaf springs with a 350 engine - Thu Nov 07 2019 12:41 PM
It's key to remember that these old trucks were designed to flex, the roads and rough service they were subjected to required some amount of give in the frame. If your after a suspension that will act and feel like a modern car or truck your may have wanted to look at an aftermarket frame such as Art Morrison or TCI. A lot of engineering has gone into these new chassis setups.
Posted By: Hotrod Lincoln Re: Original leaf springs with a 350 engine - Thu Nov 07 2019 08:55 PM
Unless you've already got a lot of time and money invested in frame modifications, check into using a Dodge Dakota frame and adapting your stovebolt sheet metal to it. They're designed from the get-go for V8 power, the parts are readily available in salvage yards, and you won't be paying an arm and a leg for somebody's hotrod adaptation of a suspension system built for a compact car. Just because somebody wants to solve all my problems by selling me something doesn't necessarily mean he's got my best interests at heart. My advice might be just exactly worth what I'm charging for it, but at least consider a few alternatives to butchering up an original frame, or paying outrageous dollars for somebody's unsubstantiated promises.
Jerry
Posted By: coilover Re: Original leaf springs with a 350 engine - Fri Nov 08 2019 05:39 PM
You have me confused. If you go the MII route the only leaf springs will be on the rear end. Choose the MII carefully as they range from well engineered (Fatman) to el cheepo ebay units that make us cry when they're put on the alignment rack. Here is a pic of a decent unit where the steering rod boot clears the frame to a cheap one that requires serious frame surgery for clearance. Neither are the $$$ ones but show what a bit of shopping can do even in the bargain units. The last pic is just to be a smart a$$ for ones with really deep pockets.

The decent one:[img]https://i.postimg.cc/68K0NxR2/IMG-4756.jpg[/img]

El crapo unit: [img]https://i.postimg.cc/d7Pm9PQt/IMG-4888.jpg[/img]

[img]https://i.postimg.cc/6y69yydB/IMG-4672.jpg[/img]
Posted By: Rocket man Re: Original leaf springs with a 350 engine - Sat Nov 09 2019 08:40 AM
Coilover

Is the decent one a Fatman? I assumed all Mustang II's would require the semi-circle notch to be cut out of the frame for clearance issues. I haven't got that far yet so my investigation into them is very limited. In addition, I'm not a welder...are there M II's that are A., bolt-on, B., no-notch and C., decent?
Posted By: Hotrod Lincoln Re: Original leaf springs with a 350 engine - Sat Nov 09 2019 12:43 PM
I'm not Coilover, but yes, there are bolt-on M-II systems. Unless you do some custom fabrication while installing that type of independent front suspension, you'll end up with a truck that resembles a redbone hound after a close encounter with a skunk- - - - -nose dragging the ground as he tries to plow a furrow half a mile long! There are ways to avoid the "droop-snoot" look, but only by modifying the height of the M-II crossmember. That definitely requires welding and fabrication skills. Generally speaking, IFS "kits" are a good way to shovel sand down a rathole, dollar-wise! The "good" ones are horrendously expensive, and the cheap ones make you spend a lot of extra money making them safe and reliable. If you don't have a lot of experience building suspension systems from the ground up, you'll be much better off finding someone like Evan in your neighborhood and paying him to get the job done right the first time. Far too many of the hotrodded cars and trucks I have to share the road with are nothing but rolling death traps, and that includes some of the very high-dollar "resto-rods" that I inspect for potential buyers overseas. One guy from Australia keeps me busy- - - - -40-something inspections in the past 10 years- - - - - he's bought about half of them based solely on my photo shoots and test drives. He pays top dollar for this old geezer's opinions!
Jerry
Posted By: coilover Re: Original leaf springs with a 350 engine - Sun Nov 10 2019 04:11 AM
No, the decent one could be from Chassis Engineering, Speedway, or in that price range. The bigger buck ones are from Fatman, Heidt's, etc. There are several that are bolt on and have steering rod boot clearance---Chassis Engineering come to mind. If a boot just rubs the bottom of the frame but is not flattened by the contact a little heat and a BFH will give the needed clearance. Of course the shoe makers kids go barefoot so my 34 Chevy with a Heidt's has been rubbing the boots for years. When one rubs through and starts dripping grease I'll expect everybody to feel sorry for me.
Posted By: floaterboy Re: Original leaf springs with a 350 engine - Thu Nov 14 2019 07:20 PM
I installed an IFS kit from No Limit Engineering on my '56 3100 and had no issues. It is well designed and and performs as advertised.
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