My 1967 Belvedere II is a 383 4 barrel car with a 4 speed. It has the 68 383 hp cam (268/284 .450"/.458") and a 68 intake and carb with 68 exhaust manifolds. It is a low mileage car, but was drag raced in the late 60s. I took it out the other day. Although I have owned it almost 4 years, I've never tried spinning the tires. I tried to do it from a 10 mph roll, but it wouldn't do it. It didn't bog, but he low end just feels lazy. It seems to run really good once it gets to 3000 rpm.

Shouldn't it be able to spin bias ply F70-14 tires? Not that I am trying to win a burnout contest. I've just always felt the bottom end performance was lacking, so I did it as a test.

Thoughts?

From 10pm on F70s……yeah…it should, assuming you are in first gear.

I had a 66 Belvedere with a 361 automatic and it would do a rolling burnout with 3.23 gears Take a look at your timing curve first then check your accelerator circuit on the carb. I had the light springs in the distributor so I had full mechanical advance at 1800 RPM. I had an old Weiand dual plane with a 3310 Holley.

Gus

Clutch slipping?

Lot's of variables to say yes or no. It takes a lot of torque to break the tires loose on a roll. I would check the timing as suggested but IMO it's asking a bit much out of a stock 383. What's the RPM at 10MPH in 1st gear?

Agree, but there's some missing info here like what rear gear and if it has Suregrip or not?

My 383 4 speed Roadrunner with 3.23 suregrip would not break the tires loose from a roll.

My '68 383 727 Roadrunner with 3.23 suregrip would not break the tires loose from a roll either....but would from a stop with brake torquing it.

It could be. The clutch does feel like it is nearing the end of its life, but the rpm didn’t jump up when I hit the gas.

I forgot to mention, it is a 3.23 Suregrip.

I don’t know off the top of my head. I was watching the road when I did it!

Probably not
My 1963 415 stock (not blue printed yet) HP Max wedge Belvedere automatic with the stock converter in it wouldn't spin the F78x14 from a ten MPH roll with 4.56 gears in it when i bought it in 1973

Maybe the timing is a little retarded, maybe the timing chain is getting sloppy? Maybe the throttle linkage isn't opening the carb all the way?

Or maybe a little of all three.

Tom

Even with all of those corrected I still don't think it will "burn the tires" from a roll with 3.23 Suregrip.......well not on a dry road.

I’ve seen it twice in my lifetime where the factory timing chain was not marked correctly and the timing was off. In both cases, it was retarted. One was on one of my 340s I installed in a truck. It had no low end torque but ran like a scalded dog after 3500 rpm. I built it before I knew anything about decreeing a cam. I degreed it when I pulled the motor and installed it in a car. With the marks lined up properly, it was 8 degrees retarded. Then a friend was building a 340 and noticed the piston was way down the hole when he was lining up the timing marks on the chain. He called me to degree it and it was off one tooth and 16 degrees! That 340 had always been a dog. I used that knowledge when I built my jr dragster motors. I retarded my big 7.90 motors ( 3 x 3.5) 4 degrees. It kept them from spinning the tires at the hit but they ran 88 mph at the stripe. They would pull hard on the big end. I sold one motor to a friend and he sent it off for a rebuild. It slowed down 4 mph!

Way too many variables.

Type of tire, type of surface, how well suspension works... For example, my car doesn't spin a tire off the hit but also runs a 1.36 60 ft. time.

The only way to know what you are dealing with is to get some time either at the dragstrip or with a dragy.

Most cars of this vintage desperately need a distributor re-curve. Throw some Mr. Gasket #925B springs in it, set the timing total at 34* and make sure the mechanical advance works correctly.

I've probably had about a dozen 383s and a few 440s in '67-'70 B-bodies through the years.
Stock, some were definitely stronger than others.
A couple of the AT cars would definitely light 'em up from a dead stop - probably torque multiplication via the converter.
I don't recall if all the AT cars would, though, but 2 stand out in that regard. Most all had 3.23 SG and got radials for street driving.
Of the 2 383 4-speed cars I currently own, one is markedly stronger than the other, but it was blueprinted with NHRA-max CR from its days as an F/Stock car and the other is a stock rebuild.
Both currently have 3.23 gears & SG & same tires.
Bring the revs up a bit and both will light 'em off, but I haven't bothered trying that from idle.

Jigsaw is a 383 4 barrel with a 280/474 cam. 727 with 11" converter and 3.91 gears. 255-60-15s.
It will peel out from a dead stop.
It will smoke the tires when power braking.
It will not smoke the tires from a 10 mph roll BUT if I had a 4 speed, bringing the rpms up to 3000 and dropping the clutch would do it....theoretically.