Help me hook, please!!

After a lot of time and money, my car 60-fts slower this year than last. Here is the basic info on the car:

• Street/strip 70 Duster, has run 10.50's @ 128 mph, 1.55 60-fts.
• 440/500 with ported Eddy heads and 260 degrees @ 0.050 solid roller. I shift at 5.8K rpm. Engine is very torquey
• 727, 9.5” converter, flashes to 4500 rpm. I'm foot-braking the car
• Steel body, 3300 lbs With me in it
• Calvert mono leafs and shocks, Caltrac bars, 9x30 M/T ET Pro Drag radials

What's changed lately:

• SS springs to current Mono-leafs

• New Calvert rear shocks, set to 7 (used to be Comp Engineering)

• Re-positioned leaf-spring perches (they broke). Pinion angle now 2-degrees down to driveshaft. It used to be a bit more than this

• Bias-ply 10.5 x 30 changed to current 9x30 radials

I was out at the ANRA event over the weekend and got 60-fts anywhere from 1.9 to 1.58. The tires spun a lot. Even the 1.58 was spinning pretty good. The 1.58 came from 11 lbs In the tires. If I run more or less pressure it results in more spinning.

My pressures on the radials are below M/T's recommendations, but the low pressure is needed to prevent spinning. The tires also move an inch or two on the rims on each pass (even after gluing). Speculation is that the low pressures contribute to this

The 9-inch radials were recommended to me. My gut told me to go with 10.5” tires, but I was told the 9-inch tires should work fine

My 10.5” bias tires seemed less finicky and more consistent

What mountiing hole are you using for front spring mount? Upper or lower? Are your bars close to parallel to ground?

I'm using the lower hole. The bars are pretty close to parallel

Parallel to the ground, I mean

I'm no expert by any means but 11lbs in a radial is almost half what everyone I know who uses radials run...and five lbs less than I used to run in bias plys of the same size.

Put the culverts in the top hole.

What gears do you have in the car?

Gears are 4.10

If I put even 15 lbs in the tires, they spin like crazy. There's definitely something wrong. Somehow I don't think the tires are being loaded the way they should.

Yep, go to top hole, put 18 lb in the rears and then study how much rear lift (separation) your getting on the launch. I had the same set up with the Comp shocks, changed to Vikings and picked up .15, my 3750lb now goes low 1.4"s

Tighten up your rear shocks all the way.
You will be a happy camper.

What he said and also put 20psi in those 30x9 radials and do very little burnout, just knock the dust and rocks off of them.

OR put the M/T's back until you figure it out. From what I hear a lot around here is that once you figure out the E/T streets, the radials will make you faster.

That Caldwell car is wild!

The shocks are single-adjustable Calverts. I don't know if they adjust the compression or the extension.

Also, another thing to check is how much front travel you have. The calverts work best with at least 4” +.

What size and type M/T radials are you using now? what width wheels also?
I ran the M/T 315x60x15 ET Street Radials on my old pump gas Duster on both 10 inch and 12 inch wide rims, those tires worked great on a good track, not worth a hoot on the street or on a mediocre track I ran from 18.0 to 22.5 lbs. in them.
I also had a set of M/T ET Street bias plys of the same size, width and circumference on similar rims, they worked a bunch better on bad tracks and on the street I ran from 9.0 to 12.0 lbs. on them, the best 60 Ft was 1.42 on the radials and around 1.47 on the bias plys
That car weighed 3450 lbs with me in it and the best ET and MPH was 9.993 at 134.7 MPH at Woodburn dragstrip in late August or mid September, CRS disease now
That car had a 518 C.I. pump gas 400 block stroker motor with a set of Indy SR M.W. heads, Indy 400-3 intake with a Holley 1050 CFM Dominator carb, MSD 7 ignition, 727 with a Mopar helical cut 2.77 low gear set, T/A 069J 4200 SS Hemi converter and 4.10 Dana 60 on ladder bars with double adjustable Strange coil over with 15 inches extended length and right at 7.0 inches of travel, I used a set of 150 Lb. rated coil overs on them also
That car would hook in a mud puddle in the middle of a rain storm

Thanks, Cab. The tires are ET Pro Drag radials, 9x30". The rims are 10"

how much preload would you use for the bars?

My Barracuda works best with my Caltracs set like this (all adjustments were made on a flat level surface):

Bottom hole, 1 flat preload driver side, 2 flats preload passenger side.
Rear shocks set on 6.

I also used Calverts front shocks (90/10). This combo gives a nice level launch and hooks well with my Hoosier drag radials set at 18 psi. 11 is really too low for the tire to work properly.

The car will be quicker w/ more air pressure and tightening up the rear shocks. I'd try around 17 psi to start and go up from there. I run 20 psi, but you may not need that much.
My car always ran good w/ the rear shocks set on 9, full stiff (Rancho 9 ways). I use the bottom hole w/ no preload.

What front shock is on the car???????

The front shocks are Competion Engineering 90-10. My friend thought the front end felt stiff, so I removed the shocks for my last two runs of the day. That seemed to help a bit. I think I'll try different shocks.

I'd suggest some Vikings for the front. All Viking shocks are double adjustable.
It's real easy to get some that are too loose or too stiff. Get some adjustables so you can find what your car needs.

The Calvert 90/10s are loose as hell and my car refused to hook w/ them. The Comp Engineering shocks are stiff and I've never cared for them. The Lakewood 90/10s worked better for me.
Like I said though, I run the Vikings now and love them. They are pretty cheap too...for a DA shock.

For a few dollars more get a pair of Strange double adjustable front shocks. Double check the settings on your Comp Engineering and make sure they are on the loose setting.

If you still have them, I’d start by putting the old tires back on.

Cal Tracs didn’t make my car any quicker, but it was consistently good.

I ran normal rear springs(xhd) with mine, CE shocks on all corners, bottom hole, almost no preload.
1.51 60’ @3670lbs with a 383(typically 1.54-1.57).
9x30 Hoosier radial slicks, 20-21psi.

Unfortunately, I sold the old tires or I'd definitely put them back on, at least as a test. Those bias tires liked low pressure too (7-8 psi). I've heard the Hoosier radials would work well for my application. Someone said they don't have as stiff a sidewall as the Mickeys, but I don't know if that's true or not.

This guide was helpful to me

Just to be clear, I was running radial drag slicks...... not any kind of dot drag radial.

What I ran previously were M/T 29.5x10.5 bias ply drag slicks..... at around 12-13lbs.

Those were with a different motor and no Cal Tracs(3400lb SS springs instead).

Wow.... running a M/T 10.5 slick and even those I go to the box at 13.5psi

That's really interesting

Are you saying the Calvert shocks are -7 clicks from full tight or full loose? If they're-7 from full tight they're too loose. Guaranteed the front is too loose. As stated here the air pressure is way to low.
Doug

7 clicks from full loose. I think they can go up to 9, which would be full tight, if I understand correctly

I'm not patient enough to read what everyone else has stated above, but if you haven't figured it out already... radials can require a very different chassis setup than bias-plies.

Things I found critical getting my car to launch straight and stay hooked up:
1. Needed to lower my front ride height and cut down my upper control arm bumpers to get the 5+" free travel from static height; before that it would hook, then top out the front suspension and unload the rear tires
2. Only required about 1/3 turn additional pre-load on the passenger side to get it to go straight
3. My shocks are the OLD Ranchos that have 5 damping adjustments and mine are on 4 (one from stiffest)... and I'll probably need to upgrade to a decent DA in the future
4. Tire pressure... even 1/2 psi too low and my 275/60R15s would squish the sidewalls too much off the line; on skinny 8" rims they needed 17.5 psi to work OK and I've yet to try 'em out on the new 10" rims
5. Don't stage your car at such a high RPM that you're torqueing up the suspension; bias-plies can be a crutch for that, but radials need the pitch rotation to stick
6. Marginal tracks and radials don't get along well

This is very useful info, Brad. I really appreciate it. Thanks to everyone

I also run 30 x 9 Hoosier radial slicks all the time on my 63 and it hooks great for what it is. Which is a street car on SS springs and just the longer rear shocks as I don't have adjustable shocks on the rear and no pinion snubber. I use the CE 90/10 shocks up front with stock suspension. I run my radial slicks around 18 psi. And I use a Dynamic 9.5 street/strip converter that flashes about 4200. My best 60 is a 1.50 at 10.70's but I usually always 60 from 1.50 to about a 1.53. Myself I love using the radial slicks over the bias as my car hooks as good on them and handles much better on the radials since I run radials up front. Not to be smart at all but you are staging in the tire groves I assume ? I know as long as I stage in the tracks where all the cars have been launching I hook great but if I don't stage in the tire tracks it wont hook as good. Good luck , Ron