Help needed to get car to mid 11's

[Frankb]

Have a 68 Charger that I want to get to 11.5 in quarter. I don’t know what the car weighs but should be a few hundred pounds less than stock.

The car has:
400/511 440 source stroker 600HP/650TQ at 4500 RPM on pump gas
727 (sportsman series) built by Protrans. Billet internals, reverse manual valve body, 3400-3800 stall
Cheeta shifter
Strange S-60 with 3:55 gears
New rear springs from ESPO, 6 leaf HD
Super Sniper w/ hyperspark
Walbro 255LPH intank pump. 3/8 pressure line 1/2 return line
1 7/8 TTI with complete 3-inch exhaust, X pipe, super turbo mufflers
QA1 adjustable shocks all corners
Chassis stiffened with torque plates and frame connectors

Street car. Runs excellent but now I want to race it. Engine built for torque. Am looking to go 11.5. Car will not get a roll cage. I want to keep the 3:55 gears

Need advice on what to do next. Car has never been to track so I don’t know what it will run now. Car will not hook up. Absolutely need better tires. Fuel system designed for street, not race. No issues with fuel starvation so far but never pushed the car to max on street

I did this car not to race but to have a fun street car. I spent a few years upgrading the car’s systems to match current power level, but I never intended to race the car. Until now. I have about 8 months to get where I need to be.

Your thoughts

Frank

 

[Geoff 2]

Should run that NOW.
3900 lb car [ without driver ] 455 engine, under 600hp, Turbo 400 with 2800 stall c'ter, idles at 900 rpm in drive, 3.31 axle, ran 11.47 with RPM intake & TQ carb.

 

[R413]

Will need slicks, shorter the better with 3.54 gears. Bit taller tires hook better. A drag tune on your fuel system will help. Then go run the car and weigh it. Maybe a low gear set in the trans if your refuse to go 4.10 gears.

455’s have plenty of torque, gets the weight moving nicely.

 

[dvw]

If it hooks you'll be looking for a roll bar.
Doug

 

[Frankb]

What would be the correct type and size of rear tire? Slicks? Drag radial? No problem changing tires at the track but a street legal tire would be fine with me - if it will work to get to 11,5. I'm also concerned about the rear springs. I really don't want to change them. I've read that others have installed SS springs or caltracks. Would I need to do that to get to 11.5?

 

[33 IMP]

If you were a stick shift car, I would 100% recommend real slicks. As you are auto, drag radials should work okay, get the biggest that will fit under the car. Mickeys or Hoosier. (I don't have much faith in toyos, nittos, or M&H. Some have made them work.)
If your willing to change at the track...... Mickey ET street radial PRO, in 275 60.
Real racers have been in the 4s in the eighth on them. (mid 8s quarter).

 

[R413]

Keep in mind that is Tucson is an altitude adjust track with the elevation of 2490 ft. so 11.50 is more like 11.15. Of course I can’t find the NHRA page on this so I figured it another way.

28x9 is a good size, with 3.9 or 4.10 gears. You could go a bit wider on a Charger. I use MT ET streets and they work like slicks. Just know the sizing is different than a slick. I use a 28x11.50 ET Street is measured at the sidewall is the same size tire as a 28x9 slick which is measured at the thread.

they sell a 28x12.50 which would fit your car great.

Mickey Thompson 250960 Mickey Thompson ET Street R Bias-Ply Tires | Summit Racing

 

[moparsaver]

Use Charlie’s car as inspiration!!

 

[QuickBpBp]

Keep in mind that is Tucson is an altitude adjust track with the elevation of 2490 ft. so 11.50 is more like 11.15. Of course I can’t find the NHRA page on this so I figured it another way.

28x9 is a good size, with 3.9 or 4.10 gears. You could go a bit wider on a Charger. I use MT ET streets and they work like slicks. Just know the sizing is different than a slick. I use a 28x11.50 ET Street is measured at the sidewall is the same size tire as a 28x9 slick which is measured at the thread.

they sell a 28x12.50 which would fit your car great.

Mickey Thompson 250960 Mickey Thompson ET Street R Bias-Ply Tires | Summit Racing

I think 2500ft would be more like 2 tenths...

 

[QuickBpBp]

Biggest thing I see hurting a 11.50 pass is the gear ratio... 4.10's with a 29 inch tall tire would be the best for racing and street driving...

 

[496 polara]

I would guess you need some track runs to get a baseline. Buy some drag radials and run it. Until you know how it behaves on the track I wouldn't change anything.

 

[Cranky]

Use Charlie’s car as inspiration!!

View attachment 1559207

Charlie Keel....need to reach out to him as it's been awhile since talking with him.

 

[R413]

I think 2500ft would be more like 2 tenths...

Well ok then LOL. the math doesn’t lie
Take 11.50 X .970 and you tell me.

Hey you figure it out and satisfy yourself, just trying to tell ya that altitude is a real thing out west, you flat landers don’t deal with it.

 

[dvw]

275/60 M/T drag radial should get it done.
Doug

 

[R413]

I think 2500ft would be more like 2 tenths...

Oh you flatlanders. LOL

Tuscon had a NHRA division race in 2020.
D/S is an 11.50 sea level index, and at Tucson the index is now 11.82. Hows your 2 theths holding up? LOL.

Click this link and go to #34 qualifier.
LODRS 7-1 - Stock Eliminator Qualifying, Saturday Final Order

 

[QuickBpBp]

Oh you flatlanders. LOL

Tuscon had a NHRA division race in 2020.
D/S is an 11.50 sea level index, and at Tucson the index is now 11.82. Hows your 2 theths holding up? LOL.

Click this link and go to #34 qualifier.
LODRS 7-1 - Stock Eliminator Qualifying, Saturday Final Order

I understand altitude just fine. You do realize other weather factors are at play so throw barometric pressure, temperature and humidity out the window…. My 2 “thenths” holding up just fine…Lol

 

[R413]

I brought this up so the man will understand that 11.50 isn’t 11.50 at Tucson. Just being there makes it slower, before you figure your weather.

Density altitude is a lot different than running at 2500 ft. elevation. Try it and then you will believe it.

Ps your calculator tells you density altitude is not as accurate! LOL

 

[QuickBpBp]

I brought this up so the man will understand that 11.50 isn’t 11.50 at Tucson. Just being there makes it slower, before you figure your weather.

Density altitude is a lot different than running at 2500 ft. elevation. Try it and then you will believe it.

Ps your calculator tells you density altitude is not as accurate! LOL



View attachment 1559267

Cause of other weather factors like I mentioned… at least they are honest. Cecil County is 400 or 500ft above sea level if I remember that said how did I and others make passes at below sea level? Krouse construction owns it so I guess they excavated the track down to that level for that day. It’s corrected differently everyday. It’s why you had to go back 3 years to fit your narrative.. I understand what you are saying it’s just not as much as you think due to other variables and I will leave it at that… if he runs an 11.70 there it would be about an 11.50 at a track close to sea level ALL conditions the same..
This isn’t helping the OP until He runs his car and gets the data needed anyway so I am done. Feel Free to PM me if you want to talk more.
This one from drag times shows a variable of a tenth to 3.5…

 

[dvw]

If the converter is loose enough. If the the tires hook. And it's tuned close. It should have enough power to get to 11.50 at Tucson. Take away 10% power for the trans, exhaust , etc. We now have 540 hp. At 4000lbs that should be enough to get into the 11.3x range.
Doug

 

[R413]

For anyone interested in NHRA altutie correction factors, here is their page. It’s a constant hard number, not subject to change. 2020 was the last time Tucson had a NHRA division race, so I used the most recent numbers.

Please notice there are no altitude adjusted tracks east of El Paso Tx. Thus the confusion of some folks as to what this really means.

https://www.nhra.net/2014/images/nhraracer/altitudeCorrectionProcess.pdf