Watched a car at the track, 3500 LBS SS spring on a Demon, runs 11.20's with BB. Car seemed to hook well on a 10 1/2 or 11" slick. Car is up for sale. I'll be throwing at least 500-550 Hp. Does a wider tire help with more HP? Tires need to be changed. It's tubbed. If I buy it I'd like to make any changes over the winter and just tweak it come race season. I don't need to spend $ changing everything. This will be a good bracket car in the 10's.

Do you know the 60 ft. times? What 1/4 mile per hour does it run now?
If it is 60 footing. in the high 1.50 or higher bigger tires or better chassis work may make it run better
I know of several N/A NHRA stockers that run in the mid 1.30 60 ft. and under 125 MPH in the 1/4 mile

How consistant is the car now? SS springs in a 10 second car, and most likely a torqueflite are going to want a VERY good shock. I think the best bet on the shock issue is to call a couple of DA shock manufacturers and get thier advice on what you need. Make sure you have that covered first, then see how big a tire you can put on it to get max consistancy with changing track conditions.

11.20s @ 3500# is about 435HP on my dream wheel. Turning up the power 25% is going to make it a different car. You may not be able to just "tweak" it to get it right. Shocks at a minimum unless it has good stuff on it now. Maybe Caltracs. SS springs are really obsolete.

There are 1000 hp cars on caltracs and a 10.5w.Good DAs are your friend!
I am on a 10.5w.

Putting more HP in the car usually mean that you will have to do some changes in the back end or other things to the car. If you buy the car weigh it on all four corners. A friend that is real good with chassis stuff helped out with a twin turbo small block, small tire car back half car on a radial. It was making a 1.36 60 foot but being a twin turbo car the owner thought it was OK. My friend did not agree and finally after the season he talked the guy into putting the car on the scales because he thought it was to front heavy with the engine to far forward having not been set back from stock engine location, he was correct. He moved a lot of weigh to the rear location in the Car and put a little ballast in the back also and it went 1.19 60 FT. Took a complete season for the owner and others to listen to him and now they wish they had of in the spring not the fall. The Super Stock Springs might be to the end of their capabilities and you might look into Cals or something else for the future. A simple change to Cal and shocks might be you easiest next stop. Are you thinking of upping the HP even over 550 hp in the future or making this car a total drag car then maybe you can look at other choices.

Doing some of my calcs, 3500/11.20's@119? would be 485fwhp, not too far off of what you intend to put in it. My mate ran a 600hp 440 on 13x31's with SS springs successfully, had good shocks on it and a well sorted suspension, would lift both wheels equally like a c-trac car, having a 650hp+ 470 in it now, same set up...SS springs still work.

We run a number of B-body +3500lb tanks with +500 pump gas RB strokers running 10-11 slicks. All of them are in the 10's now.

They are tough on 8-3/4 rears, and suspension parts. All of ours are now Calvert mono leaf with the rancho shocks or better. The 8-3/4's we run spools with billet caps and full back braces. Most of ours are 60fting right at 1.50...Some of them are street driven.

My 605 Hemi runs Calvert's and mono's and 60ft is 1.35 with rancho's but double adjustable coil overs on the front and I run a bigger rear tire.

Best investment you can buy for a mild bracket car or even a faster one.

My heaviest car, 3440 pounds went the fastest, and most stable on the other end with a MT 33 10.5W 16. 1.16 60

A 550hp car will hook pretty easy on 10.5's. I've seen plenty of N/SS 10.5 leaf spring cars with low line single adjustable. They run well into the low 10's. I run 10.5wx31 with Koni doubles. Car hooks anywhere. Has been as quick as 1.240 on the footbrake at 3445lbs.
Doug

You’ll never know what the car needs until you run it for a while and make a few adjustments to what’s already there. With a well sorted chassis and suspension, a 29x10.5 should hook just about anything. If it’s running 11.20’s at 3550lbs, it’s already very near the HP range you’re talking about throwing at it.

This may be a redundant comment, but here goes anyway.

Shocks, shocks, shocks.

They make anything work. Case and point, my heavy old plain ladder bar car had 1.27 average 60's, put on some electric Koni's, and bang 1.2 60. Kept messing around with tires, and a little better here, and there. 1.19, 1.18. Then one day the car wouldn't hook on any tire, back to 1.25 ect. Stuck a set of fresh penske's on there, and wham 1.16 with the 10.5 tire. The Koni's bent the shim stack, and went back to being pogo sticks. They're going to get rebuilt and sold.

Had a new set of Penske's done for this car, and waiting to get a weather break to try them. Hoping for an even better 60.

Long way of saying, the best money you'll ever spend on suspension is shocks.

I've has 10.5 for several years with different SB combos and they work well. As stated this car is tubbed and needs new tires. A 12" would fit easily. I'd like to take advantage of the larger size tire and see what it would do. I've got some HD wagon shocks that are extra long. So with all this info that has been discussed, a bigger tire is only a small part of the hook or is it a extra layer of stick on a marginal track condition or more?

Over powered and over size tires as we know is great for consistency. If the car works on the size that's on there just get the best M/T tire you can buy in that size. Most people don't get the larger circumference the larger the footprint north and south wise. Really where you need it the most. I will say this about the M/T 33X10.5WX16. The brakes aren't as good as a normal 15" wide deal. Although I can still kill .02 with the best of 'em! You need double adjustable shocks. I've seen some cars with wasted motion driving the rear end into the ground. This can be super frustrating as the car initially hooks then unloads. DAMHIK!

I only run a 30 x 9 Hoosier radial slick on my 63 It is just a street car that I take to the track sometimes. My setup is very old school as I just run the 3400lb SS springs and the longer MP shocks. My shocks are just a standard shock with no adjustments at all. My car weighs about 3725 to 3750 depending on how much gas is in it. It hooks great on just the SS springs and is very consistent. My 60's are just average for an SS spring street car as my best 60 is a 1.50 running 10.70's. I am sure with Cal Tracs I could 60 ft better and pick up some et but I don't think I would pick up any more then a tenth at best and its not worth me spending the money for that. I may try adjustable shocks in the rear one day to see if they help any but the car drives so nice and works fine at the track as it is. Ron

That's for sure. You have to almost completely stop the hit motion of separation, then let the body come down on it slow and steady while it picks up wheel speed.