I doubt it saves any weight. It's all about unsprung weight. Total weight of everything on an IFS, below the springs, has to be less than that of a solid beam axle and it's components.
I doubt it saves much, if any weight. A tubular straight axle is probably a little lighter than a beam, but with one or two leaf springs and brakes, the whole****embly be close to the 'A' arm suspension, in my guesstimate. You mention an aluminum floor. Considering the original steel floor in your Plymouth is also a main structural component, it's what mates with the frame body mounts, you'll have to figure some way of keeping the structural strength intact. Also, figure how to best mate the aluminum floor with the steel body at some juncture. Maybe a full roll cage would add the needed upper support, but there goes any weight savings. 14-1 compression is pretty ambitious. Good luck with your build. Ray
Building a 318 that sees 8000 RPM will probably get you into the MOPAR Hall of Fame. As far as weight is concerened the stock front suspension you have is probably the lighest ever to come on a production car. I'm not trying to discourage you but the amount of money you are talking about spending on this build would go a long way toward buying your new Challanger.
Heres some advice from someone whos wasted too much time on "ambitious" projects. Leave the aluminum floors for the race cars...the full roll cages too. Don't get carried away with the engine plans either. Build yourself a good solid car...with or without a straight axle. I know your floors are bad, but aluminum isn't gonna make anything easier. You have a good solid frame to work from, so rebuild your floor and mounts properly, in steel, to fit it. It will be MUCH easier and you will have a real car after you are done. Worry about the engine etc once you have something solid to put one in...
Any weight savings with a straight axle would come from replacing frame and cross member with square tube set up as well. Straight axle usually held up better when doing hard mombo though.
yeah the axle is about weight transfer not weight savings but that's been covered. Interior: if it were a street car yes it would have had some sort of interior or at least the hope for one. But your building a race car that sees the street. That thing would be mega gutted. I've seen old drag cars that not only have no interior but everything from The door jambs to the quarter panel bracing has been speed holed all to hell
As an alternative to a new Challenger........find a 'damaged' Challenger or Charger with the 6.1 or 6.4 (392) and for the same amount, or less, than the warmed up 318, you'll have a street scorcher worthy of the name and with reliability too. Not a HAMB endorsed engine, but it works! Ray
No weight savings??? Really guys?! Put 4 a-arms, 2 tierods 1 draglink , 1 idler, 2 coil springs , cross shafts , coil pockets , big**** spindles and****orted hardware on a scale Now put one axle , 2 short little leaf springs , little spindles and brakes , a tie rod and draglink ....on that scale .. I bet you cut the weight in half , in a world were they drill 1,000s of holes to save a couple pounds... That's huge!
You're building a '56 plymouth? Its going to be a wheel stander, or do you just want it to stand up and cut a straight line? About '65 they changed the rules up for gas class cars. Your interior could be more abbreviated than in earlier years. You still needed something that resembled an interior but I think you could run back seat delete, a '65 rule book should be easy enough to find. search gasser rules or gas class rules. There is a thread that covers them for a bunch of years. I doubt that you will actually save much with the axle. A lot depends on what you use for an axle. I have heard numbers like 30 or40 pounds bandied around for years. I have never weighed one to find out but like all things you hear in the pits the numbers may be mildly exaggerated. There actually were less straight axle cars being raced than you would think. If you want it to stand up and cut a straight line and expect to be cutting a fat hawg in the**** on the big end you may not want to lift it much. A couple of inches is a ton and little to no lift on the rear will give you plenty of weight transfer. Stock A arms drilled are no longer legal but that used to get done. You can still lift your stock suspension 2-4" easy enough. You don't change your quench by altering the combustion chambers. quench is the distance from the top of the piston to the mating face of the head (that is overly simplified but will work for the sake of the current argument/discussion). That said if you are serious about making HP CCing he combustion chambers is a good idea. The chambers may need a little work to unshroud the valves. An 8K anything is going to want bigger valves in both holes. You may consider keeping your compression down around 12:1 maybe 13:1 max if you are planning to run gas. 14+:1 is alcohol numbers. Just a thought. I won't go into the floor boards and cage deal you got more to chew on now that you asked for.
Sounds like a 13 second car witch will not need a cage.I dropped the front of Wasted 4 in. and picked up 1.5 mph.
If you have bad knees try taking Sam E and vitamin c. Sam E is the only thing that will regrow worn joints. Try it for a month and see. Costco sells a good brand. What are you trying to accomplish with the car? I cannot make any sense out of your questions. If it is not going to be run on the street is it for racing? If it is for racing why not build a car that can win? The way you are talking about building it, you could not have won a drag race even in 1960, today they will laugh you off the track.
^^^^^^..............................^^^^^^^^^^^^^^^^^^^^^^^^^^.........................................^^^^^^^^^^^^^^^^^^^ and I can hear a lot of laughs here on the HAMB already
There is a thread over on Tri five asking the same question? How much less if any does a straight axle save?
Now we are getting somewhere. You have a rusty car and are trying to figure out what to do with it. I think we have all been there. If you don't have the skills, tools or money to fix it, it is good you figured that out now. And did not put a lot of money and time in with no chance of finishing it. Probably the best thing to do would be to sell it for what you can get, and save up for a better car. Get something that is at least all in one piece and drivable. Don't over match yourself in your first bout. By the way I was not kidding about the Sam E and vitamin C. They cured some long standing back and knee problems I had, and helped some friends with similar problems. At least do a web search and see if they might help you.
To quote squirrel's tag line: "begin with the end in mind". Some of best advise I have ever seen on the hamb.
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