lugnut

iTrader: (1)

I been trying to do this on my own,but dont have to much experiance with stock supension This is my second time at track.
First on was at kanawha valley,nice place.I had M/t et street tires,26" went 8.07 with a 1.67 60ft,spinning the rest of night was 8.00s no traction,then broke a wheel stud Got new moser 31 spline axels in 9" ford,and put on 28" tall slicks.Now Still 1.70 60ft and a best of 7.86 but the tires are spinning on rims.I dontwantto put screws in brand new welds,so went back to et street tires I just cant get it to stop spinning Got frame ties,tube control arms,BMR adj torque arm relocated to trans tunnel,adj panhard bar,all good stuff,also bought a set of drag air bags My mph is 86.50 I just think it should go faster
Mild 454,.540 lift,781 heads(stock)roller rockers,Air gap intake,9:1 700 dbbl pumper,th350,3800 stall,and 3:70 gears
What tire pressure would you start with,with ET streets?
Also 8 point cage,headers,through 3" mufflers
I know its not a beast of a BBC,was supposed to be more street than drag,you know how that ends up
I had the slicks down to 12lbs when they started spinning on rims First time out with M/T had way to much air in them 28lbs,I know
Next trip out,thought about 18lbs to start,thoughts?

bobby hill

iTrader: (1)

If you haven't already, check your rearend geometry. Research lca angle, pinion angle and weight transfer. Lots of good info on this site. I run low 7's on slicks consistently but that is with a small block. Running the big block with the extra weight on the front might be alot of your traction issue.

Shagwell

Control arm relocate brackets? - Single biggest gain for most cars launch traction wise. What springs & shocks, front & rear?

As for spinning the wheel inside the tire, look into the bead glue. There are some killer glues out that will negate the need for screws.

lugnut

iTrader: (1)

NO control arm relocate brakets Guy I bought the car from said he ran a 406 in the low 7s He never said nothing about it not hooking up,so I havent done nothing to rear suspension other than air bags lake wood 90/10 and lakewood 50/50 drag shocks on rear

built91Z28

The control arm relocation brackets work. I'm only on street tires, but I use to not be able to go to the floor at all in 1st. No matter how late I waited in 1st gear, it would spin. Put the brackets on and now I just ease into it, and by 3000 rpm I can floor it. Sometimes it will still chirp, but for the most part it hooks now.

AlkyIROC

How good is the track known for doing track prep? You might be doing everything right however if you're running on street legal nights, track prep may be poor. You may have to go during a bracket day to see good prep all the way down the track. Then you should be able to power your way all the way down the track without spinning.

12 psi is a good starting point. There is no right or wrong pressure since each car is different however 1 psi per second is a good starting point (1/4 mile). Your time works out to a 12 second pass so 12 psi is a good starting point. Adjust the pressure 1/2 pound at a time in both directions until you stop spinning off the line. If you're running tubes and the tires spin on the rims, you'll rip the valve stem off the tubes. Glue or screw the tire to the rim.

Your "stock" 781 heads need some work. Install 2.19/1.88 valves and do some port work to really wake them up. Don't expect big results from unported heads with stock size valves. .540 lift for a 454 also a little small and still basically a very mild street cam. Something in the low to mid 600's would be better and it would still be driveable on the street.

DIGGLER

iTrader: (1)

i dont see why the wheels are spinning in the rims... that is odd to be doing that already. how does your weight transfer look? does the front come up at all? you have a much heavier engine than the other guy had, and he also had more power and hit the tires differently than your combo.

lugnut

iTrader: (1)

It hits pretty hard,the front goes up some,but i know its heavy
I know the combo is mild,just wanted to see what a warmed over BBC would do
I will try it with 12lbs air in the street radials,and go from there If istill have problems i will buy the brackets
Thanks for the advice

84firebird383

I can't see you having traction problems as bad as you think with your combo and 60'. Its your first or second time out so it undoubtably has a bit more, but it really seems right now that you are about where you should be. You won't hook on normal street radials no matter what. if you want to race on those then foot break it to max rpm when the lights come down at the line, and then just let the car launch by taking your foot off the brake and gradually put your foot into it trying to find the sweet spot between wheel spin and moving forward.

84firebird383

Do not air down the street radials. they will cup and give you less contact patch.

84firebird383

I could be wrong, but it sounds like he has a hydrualic flat tappet. good luck finding a mild .600 lift cam in a hydraulic flat tappet. If I am wrong I apologize sinscerely. I have a .670 solid roller and run in the 10's (1/4 mi)with a 3850lb rusted out 77 fireturd. I don't think his cam is that small at all for a mild454. probably just right. I do agree on the heads. They are not bad for stock and can be hopped up nice, then you can add a larger cam and really go fast on a budget

lugnut

iTrader: (1)

Thanks firebird,you are correct it is a hyd cam which runs out of steam around 5800 I shift at 5500,I think is plenty I just wanted to see how a BBC would run,with little done to it Im sure it could use more convertor,its a swap meet special,Im just playing around right now,getting use to car,this is my first FB car,the rest had electronics,so Im used to leaving on the wood
Thanks

greezemonkey

iTrader: (14)

The first bbc I put in my car was a .030 454, it replaced a 400SB that ran 12.0 1/4. The BBC when first dropped in ran 12.0 as well. I had a hyd flat with .550 lift. when we went to a solid flat tappet with .620, more duration as well it responded by almost touching the 11`s. now I had a 850, 10.5 to 1, an old world product heads. Mine never hooked as well, 1.6 was good for it. The problem was the suspension was getting loaded before the launch, I would foot brake it to 2000rpm and the rear of the car would rise and then went let loose it would just spin, no stored energy. the front was so heavy that it wouldnt transfer any weight on the launch. How are you launching it? off idle may be best, flash the converter. Also 28`s and a 3.70 is not that conducive to a fast 60`, unless you running some n02. that 9 inch takes some power to turn compared to the std 10 bolt.

video your launch it will help when you can see what is happening

AlkyIROC

Oops. I must have missed the part on having radials. Start at 18 psi and move up or down 1/2 pound at a time. Radials do not like low tire pressure. You may find they work best in the 18-32 pound range.

Shagwell

Definitely don't go below 18ish in the radials, as noted they will cup up in the center and spin worse. 20-25 is usually a good range for radials.

I agree with greeze on the launch; often times it's best to straight flash stall the converter from idle, but it takes a reasonably well dialed carb to co-operate.


Definitely a mild cam for a BBC(we use similar in mild boat motors), but it's still a bbc with half again more low-end torque than the sbc it replaced. It's gonna hit the tires harder and require that much more traction to make it work well. - As noted your current 60's aren't that bad, but there's definitely more on the table.

Dialed_In

iTrader: (3)

My car is 3500 lbs with a pump gas 383, 3.73 gears, TH400, 3500 converter. Suspension is stock-style with Spohn torque arm, lakewood LCA's with relocation brackets. I run 28" MT ET radials with 18 psi and the car 60's in the mid 1.4's. Footbrake car leaving at 2500 RPM.

1.70's....somethin aint right.

lugnut

iTrader: (1)

I been leaving at 1500,cant get anymore out of convertor,prob wore out Going to try 18lbs to start with street radials I will also try leaving from a idle,and see what that does thnaks for all the replies

84firebird383

nm

unknown_host

iTrader: (1)

Switch to a single plane manifold, pick up some horsepower and mph, and lose some low end torque. I did this on my old street/strip 82 Camaro and was running 12's @ 112 on BFG Radial T/A tires. You have enough converter it shouldn't be a big deal, and would be an easy change to make.

Shagwell

Not only does he not have nearly enough cam for a single plane, if it only foot-brakes to 1500 he doesn't have enough converter either. - Unless you have enough cam & compression to utilize a single plane it will actually cost you power all the way through.

Converter is way tight, stock should foot brake at least that high.

unknown_host

iTrader: (1)

Just my opinion, I did this on my 82 and that was a 350 ci 9.5:1 350 with a 230/236@.050 flat tappet and a 3000 stall and the car went 12.2@112 on plain radial tires, made plenty of torque imo.

Oh I didn't see that it only foot brakes to 1500, I read it as he only foot brakes it to 1500 my bad. I wouldn't recommend a single plane if it stalls to 1500, that's close to stock. I would think with BBC torque it would stall much higher.

Again just my opinion, but based on his specs a 3800 rpm converter and a big block would probably gain some hp up top switching to a single plane.