Hello everyone,

I'm currently mid restoration on a 70 Roadrunner, 383-4 barrel, 4 speed manual trans, air grabber hood.

I'm trying to select which bars & springs to purchase, but I don't know how much the car weighs.

I'm looking for a Total weight for the whole car, and also just a Front end weight (only the front tires on the weigh scale), so that I have some idea of what the weight balance is like on these cars.

This will be a fun street driven car, no drag racing or autocrossing, but I'd like it to handle well.

Mainly I'm looking for car weights so that I can make my own decisions, but I'd also be interested in hearing what torsion bar sizes you guys recommend for handling on a 1968-1970 B body.
Anything to at least get me in the right ballpark.

Thanks!
Tav

To give you a rough idea of the build, it will be 11.75 power disc brakes up front with 11 drums in the rear on a 3.23 ratio sure grip 8.75 rear.

Firm Feel stage 3 power steering, Firm Feel tubular upper control arms with offset bushings for more caster.

Body stiffening: Firm Feel steering sector shaft support, Lower control arm stiffening plates, XV lower radiator support reinforcement, Resto Rick factory torque boxes (front & rear), hemi leaf spring reinforcements.

Im a fan of a 300lb/in bar minimum. Rear spring I would go with XHD's.

Despite its slightly larger size, your Road Runner will be very close in total weight and very similar in weight distribution as your Cuda. You may have 1-2% more front weight, but that's about it.


Some basic combos I've calculated for my '74 E, which is easily as heavy or more than your '70 B;

.96 t-bar with 1.25 sway or 1.18 t-bar with 1.125 sway for front combo.

160# XHD leafs with no sway bar or 120# oval track springs with .75 frame hung sway bar for the rear combo. Either of these match with either of the above front combos.

Obviously the big change in t-bar sizes can have a big impact on ride quality on public roads that may or may not be in good condition. Since I'm leaning more towards autocross capability than street comfort, I opted for the heavier t-bars and actually have stepped up to 1.22 t-bar and a .95 axle hung rear sway bar. These also were for my small block/ 4 speed set up. A heavier big block/auto combo would most likely do better to keep front t-bar sizes in the 1"+ range.

Find road test articles from magazines. They generally listed curb weight, test weight and front/rear weight percentage. Brookland Books has reprinted many of these reviews.

If you are resto-modding then aluminum bits and headers will shift some of the nose weight down and back in comparison to a straight up restoration.

Tires are a big factor often overlooked in suspension tuning. Todays tires generally have better grip than any 1970 street tire. A tire used in competition will change the whole way the weight shifts around and puts greater demands on the springs and shocks - especially the front. For the street, especially as a starting point, copying an autocross setup could be a bit stiff.

Tony's suggestions above are good.

FWIW...my 1970 Road Runner coupe weighs in at 3560#'s 383 4-speed car with nothing else on it.

Where do you find 160# leaf springs?

Espo said the biggest they had was 130#.

I put Mickey's 70 Hemi 4 spd Roadrunner post on 4 corner digital race scales recently.

I'll post results...

Wow, that would be really helpful!

Currently, I'm thinking that I'll run
1.00 Torsion Bars
1.125 Front Sway Bar
Leaf Springs 160 lb
No Rear Sway Bar


I'm guessing that I'll have about 56% of my weight on the front, but that's just a guess.


I figure that I can either add a .75 rear sway bar, or change the front sway bar to 1.25 if I find that I need to make one end of the car stiffer.


What do you guys think?
Will this setup be to stiff for a street driven car on 15 inch tires?

Mickey's 70 Hemi 4spd Road Runner post/coupe. It has a MP aluminum hemi six pack manifold and holley carbs, MP cast iron block. Cast Iron 4 spd, Dana 60. Stock front disk. Bench seat. Gas tank is not full, but forgot how much gas he had.

Don't know about?:
-rear brakes
-cast iron or aluminum heads
-cast iron or aluminum bellhousing

The percentage is set on Rear. So the first reading w/o driver is 45.7% rear weight (54.3% front). Second reading is w/driver at 45.9% rear weight (54.1% front).

It's the weights on screen with the arrows pointing on them divided by the non arrow weights.

w/o driver:
LF: 1079 RF: 1005
LR: 848 RR: 909
F/R%: 54.3/45.7%
Total: 3841 lbs

w/driver:
LF: 1155 RF: 1022
LR: 912 RR: 933
F/R%: 54.1/45.9%
Total: 4022 lbs

Thanks, that's incredibly helpful!

I'm guessing that my built like original, iron 383 will weigh more than his aluminum hemi, + I'm sure my air grabber hood adds a little additional weight.

I'm also running a stock iron 4 speed with the stock aluminum bellhousing.

I have buckets and a console instead of a bench seat.


My guess of 56% front weight might be reasonable, but the overall weight is a bit heavier than I imagined, which I think makes me less concerned about the stiffness being high.

That's consistent with 'Hemirunner's weight from FBBO. I believe his '70 is 4050 lbs with a megablock based hemi with aluminum heads.

My '70 also has a megablock based hemi (iron heads) but is completely stripped of non-essentials inside and out. Basically a shell with only the parts to be road/dragstrip legal. It weighs 3680 with me in it. 3500 without.