Leaf spring w/ Caltracs

Just wanted to pass on some stuff I recently learned working with my '69 Mach's suspension that might help somebody. I have my car setup to look sorta late 60's "super stock" -non tubbed, no graphics, no big scoops/wings/lexan, leaf springs, full interior w/ glass, ect. Only a lift off, stock appearing hood. For guys running Caltracs on milti leaf setups in classic stangs here's what I found seems to really work well. This is on a 3300lb, 10.5 slick, BBF car.


Because the car is fairly nose heavy I set up the Caltracs in the lower hole to push the IC forward and lift more on the front of the car rather than the chasis' center. I leave about 1/4" gap (zero preload). I removed the lowest(smallest) leaf from the stock pack. This changed the action back there dramatically. I clamped the forward half of the spring pack right down tight. I left the rear section of the spring pack (behind the axle) entirely un-clamped. I used axle grease in the shackle bushings and installed locking nuts on the shackle bolts so as to secure them but not draw them down real tight. The shackle has to be able to move freely without binding. 50/50 el cheapo drag shocks back there.

Up front I have moroso drag springs for BBF in a '69 stang with 1.5 coils cut and Calvert 90/10's with a 1/4 inch spacer on them. I have just a touch under 5" of front suspension travel. You can lift up on the front bumper and pull the nose up to full extension with minimal effort and it settles back down nicely.

The car's stance is fairly factory- completely level and perhaps a little bit higher than stock. But this is with 28" slick on the back and a 26" skinny up front.

The car absolutely LEAPS now with this setup off idle to wot from a dig. Violent, hood heads for the sky, dash in the lap kind of leap. On a concrete driveway with cold slicks. Drastic improvement from previous setup. I'll report the 60's after this weekend weather permitting.

Good info! Thanks

So my 60' times actually suffered a tad.

Here's what I learned:

The car has 4.33's on a spool with 10.5 slicks and a low gearset C6. Most would say its geared way too much, especially for a BBF and a Nos hit off the line. Remember I'm a mile high here. It was hooking damn hard -even on the bottle... hitting the tires extremely hard on a track known for its usually crappy prep. Hooking so hard it may have been "dead hooking". It was pulling the fronts 6" for a moment, then agressively porposing- unloading and reloading the rear suspension until I grabbed 2nd gear. This after-the-hit porposing ate my 60' times regardless of the small wheelies.

After talking to Calvert Racing I am tossing my $25 rear drag shocks for a set of their 9 way adjustable ones. The guy I spoke with explained how the Summit brand, Competition Engineering, ect. drag shocks don't have the mustard to control the rear end after the initial hit on the tires.

To be continued...

what was the 60' ? you may also need to put just a little preload in the bars so they dont shock the susp so hard ?

I was doing mid 1.5's. Usually run high 1.4 to low 1.5 or spin and its terrible. This time it hooked hard every time but porposed. Just have to keep them planted. I believe it will then do low 1.4's.

I believe you will like getting some real shocks back there. Last year I switched from ladder bar/leaf springs and competition engineering shocks to ladder bars with Afco double adjustable coil overs. Car leaves totally differently now and is much more adjustable. I can't say my 60 ft. times improved much but car is much less violent and more consistent. This year I'm changing the front to coil over struts so I'm looking forward to having more suspension to tune. Good luck. Keep us posted.

I guess your front end is stock? The pic with your posts looks very familiar, as my front wheels tilt out like that too!
What kind of converter in the car? And... Do you ever run on the motor? If so what are the 60' times then?
Good looking ride!

Yeah, the front suspension setup is stock with moroso drag springs, no sway bar, and Calvert 90/10's. I'm running a UCC 5000 stall converter. 60's on the motor or spray so far have been the same due to the progressive controller. I figure after I get it leaving how I want it to on motor I'll hit it with the bottle sooner and harder.

any progress?

dfree383 wrote:any progress?

Nah. Family flew into town which nixed my track plans. Soon as they leave I'll be back at it.

Made it back to the strip yesterday. Car 60' were consistent 1.52's. This is a small tire, foot brake car on craptastic track prep. I had the Calvert rear 9 way shocks set at 7. No wheel spin at all, no more porposing after the tire hit. The car was again hopping the front tires about 6" off the ground for a moment and maintaining traction with the nose way up 100' out before it would start to settle. Definate improvement. Ran another uncorrected 10.6 on the motor and 10.1 on the 125hp progressive bottle shot - shutting the nos off a few hundred feet before the traps so I didn't run a 9 (uncerted).


Everything looks to to working with the rear how it should, so now I'll start hunting around to attempt to drop the 60' down into the 1.4's consistently.

Oh yeah, my slicks are pretty shot a this point. They are 3 years old and about spent. I'm fixing to get a new pair quick.

New slicks. Went with 28x10.5 Hoosier stiff side walls. Rear shocks set at full stiff after reviewing videos. Consistent 1.47 60's again foot braking off of 2500rpm. No porposing what so ever. Ran 10.51@129mph best na pass ever with DA over 8000'. Yes, that's an 8 with 3 friggin' zeroes. Looking to possibly upgrade to spilt leaf mono's next.

4thHorseman wrote:New slicks. Went with 28x10.5 Hoosier stiff side walls. Rear shocks set at full stiff after reviewing videos. Consistent 1.47 60's again foot braking off of 2500rpm. No porposing what so ever. Ran 10.51@129mph best na pass ever with DA over 8000'. Yes, that's an 8 with 3 friggin' zeroes. Looking to possibly upgrade to spilt leaf mono's next.

good deal

I know that crappy air well after running at Desert Thunder in Midland for years. I remember telling people that 5000' was good air!

I think you would like the change to mono leafs and the 9 way rancho shock, I did. Seems the old leafs springs are heavy and with the rancho shock you will have more adjust-ability.
Justin

Yup Mono leaf is the way to go. This one has stock monroe shocks on the back. My Falcon I have the Ranchero 9000

I have been running 1.5... 60's and wondering about playing with the shock settings myself I have the Calvert Racing/Rancho 9 ways in the back of my truck with Competition Engineering Slapper bars and Calvert Racing 90/10's up front with 1 1/2" shock extensions to get over 5 inchs of droop. I have mine set at 5 and have not had any traction issues so just left them there.

this is a pretty car/picture .....

BigBlockFalcon wrote:Yup Mono leaf is the way to go. This one has stock monroe shocks on the back. My Falcon I have the Ranchero 9000