Re: 72 Lwb
 

not sure about his but mine is similar and my frame is stock!

Re: 72 Lwb
 

Truck was a leaf springer but now it has a S&W ladder bar suspension and except for small c-notch the frame is stock.
Has Moser Fab rear and S&W coilovers which are kinda cheap but soon as my bank allows it I will spring for better springs. LOL

Re: 72 Lwb
 

Truck looks good!!

Re: 72 Lwb
 

Well guys...I made a big score over the weekend. Found someone willing to sale their 496 shortblock for a killer deal.

Studded 468 block....line bored and ready for hone...clearanced for stroker
Cat 4340 4.25 stroker crank
Manley 6.385 H-Beam rods with arp cap screw bolts
NIB SRP 10.2:1 pistons
Used JE 13:1 pistons
Comp Magnum 1.7 rockers
Comp Magnum pushrods
Crower Solid Roller Lifters
Billet timing cover
Timing chain
Some nasty lift race cam that I will not use - solid roller
ATI Damper
SFI Flexplate

The price was so low I couldn't pass it up

Re: 72 Lwb
 

cool! That should be strong!

Re: 72 Lwb
 

Yea man I'm pretty excited. I have a proven combo I am gunna copy that puts out mega torque and peaks the hp right in my prefered sweet spot of 6400 rpm...the combo uses as cast AFR 305's and a solid roller off the shelf cam.

Re: 72 Lwb
 

That should be awesome! Good luck with the build!

Re: 72 Lwb
 

Thanks....I will keep you guys updated with the progress. I will be building this one myself with the help of a friend.

Re: 72 Lwb
 

Jim,

I hate to say this, but that is not how I understand it. Seperation and squat are relative to the instant center of gravity vs center of gravity. If your instant center of gravity line (which for our trucks is a line drawn from the rear tire contact patch through the front hole on the lower control arm) is bellow the center of gravity than you will induce squat, if it is about, you will induce seperation.

For a ladder bar car, your ICG is where upper and lower are welded together. For a 4-link you have to draw a line for the upper and lower arms. Where they meet, that's your ICG.


The spring will see a different leverage ratio if placed in front of the axle centerline or in the rear of axle centerline. It will see different leverage ratios based on different distances in front IE different distances behind. The weight placed over the rear (or front for that matter) will act differently on that spring due to location. In our rears, with the stock mounting position, There is quite a bit of leverage placed on the spring compared to if the spring was behind the axle. This requires you to have a stiffer rate spring in the stock location or a longer spring of the same rate vs if it were behind the rear. But, due to the leverage ratio, if you are able to induce antisquat, having the spring in front of the axle will give you more potential travel. Same goes for the shock.

The shock is controling the rate the suspension travel. Now if your shock is in front of the axle, it is subject to more leverage ratio as well as the spring. The shock is going to see less speed in front of the axle vs behind it but requre a stiffer setting to act the same as it being behind the axle in a softer setting.



What I'm getting at is with out your ICG/CG being 100% your are going to squat the rear and loose energy planting the tires in to the suspension. If you are trying to get sepperation, you need at least 101%.

Paired with the right spring having stored energy and a soft setting for expansion rate on the shock, you are going to allow the rear to seperate quickly forcing the tires in to the ground lifting the rear frame.



If you get a chance, Dave Morgan sells a book called "Door Slammers: The Chassis Book" He also has just released a DVD out based on one of his seminars. He has been doing chasis for Alston for the better of 15 years. He explains it much better than myself..

Re: 72 Lwb
 

Here is a spreadsheet I threw together. http://73-ls1.com/63truck/weight_sheet_revision_2.xls

It allows you to calculate leverage ratio for both front and rear. Should aid in figuring out spring rate/length. I have another one somewhere that allows you to figure out anti squat ect.. Actually, the Pirate4x4 site has a killer one for that..

Re: 72 Lwb
 

A lot of good info there. On my drag race suspension. Ladder bar with the traditonal perpendicular/behind the axel coil overs, your saying the rear springs play a much bigger part than I could of imagined.
The amount of seperation(anti-squat) is no more than .500-.750". I cant see how stored energy has anything to do with that. It is a function of leverage which I control by the rear shocks...I use the shocks also to control the compression(squat). Am I completely off base here?

Re: 72 Lwb
 

Think about it this way.. The front stores energy by having a long light spring right? It works the same in the rear. Having compressed that spring X" you have that much preload in it. When you induce antisquat, it's going to put the energy of the highly compressed spring to the tire.

But one thing to consider is too much will do 2 things.

It will counter act some of the front raise. The front should start to come up before the rear does. But as the rear does, It's going to want to push some back on the front.

Secondly, if you have too much energ stored in the rear, as it slams the tires in to the ground, the tires might want to bounce back. This is where a double adjustable shock can help for sure. Loose for the seperation and tight for the compression.

Dave does a great job explaining it. I have his DVD and love it. I could watch it over and over. I always picks something new up on it.

Re: 72 Lwb
 

Truck looks awesome! Lovin' the LWB dragster ;)

Re: 72 Lwb
 

Thanks....I really enjoy it!