I weighed my 73 LeSabre today and 300hp should be enough to get into the 13s

According to the calculators Derek was telling me about, 300hp and a car that weighs 4176lb should go 13s. thats well within range of the 350sbb but arent 13s unheard of in B bodies with small blocks making a mere 300hp?

Found a weigh station at the landfill near where I live. I can drive on it for free and weigh my car. It shows up right on a display as you drive in. So I went for it. I was surprised it only weighed 4176lb. That is after I deducted for gas, passengers and junk in the trunk.

Could I really do 13s with only 300hp? Wait. I miscalculated. The temp would have to be 10 below zero. Never mind. with driver and gas it would be 4400lbs. Low 14s. at 65f

I would need 325hp to propel my land yacht down the track in 13.98 seconds at 65F, 10feet above sea level, 30mb barometric pressure, and 40% humidity according the hp calculator. Is this realistic or just theory.

 

I didnt mean to give the impression that my engine currently makes that amount, only that a sbb 350 can be built to make that amount and much more according to cursory reading in the small block forum. I just thought that 13s in a B body would requre HP in the 400s and big block only need apply.

Im assuming that the 300hp would have to be measured at the rear wheels after the auto trans takes its share and the drivetrain takes its share as well as accessories.

 

To manage that with 300whp and 4400lbs you'll need to set up the car to maximize the run. The gears need to be set to be near redline running through the traps and the car needs to dead hook off the line.

It'll probably need 4.56 gears, at least a 3000rpm stall converter and slicks to get close to running that time. Not many people running b bodies are willing to do that much on a car that's better suited to being a cruiser.

 

how much flywheel horsepower equals 300 wheel horsepower? wih automatic? with manual?

 

Give or take about 350hp flywheel, manual would be closer to 340hp, auto around 360hp. Lots of variables, tire size and weight, gearing type and ratio will affect rwhp rating as well.

 

Would take an easy 450hp to run a lesabre to mid 13's

 

thats what I thought but the calculators were saying only 300 to 325 which seemed very low to me. I guess those calculators arent very accurate. I got excited for nothings. I thought "hey, this might actually be approachable"

I thought Smartin had a 71 Centurion that ran 13s and could have hit 12s he said. 455 car. no idea what mods if any he made to it.

 

what mods did you make?

 

You could probably do it if in you had 300 HP and 400 ft lbs of torque at the rear wheels. :Brow:


You need torque to move that barge! A sbb stroker would work real nice for you IMO, if you don't want to go to a 455. The added cubes would go a long way to adding needed low end torque to get that thing moving. A mild roller cam with at least .550" lift with around 202* and 212* dur @ .050" with a 112 LSA in that stroker would get that barge moving real good!(ask me how I know) Of coarse head porting would be needed as well. GL









Derek

 

how much hp does a TH400 siphon off vs a manual trans? I heard its quite a bit more than just 10 or 15. What do you think Larry?

 

once it starts pushing air it will gobble up HP

 

how much wind resistance is that calculator factoring in to arrive at a needed HP of 300? I mean is that for a bullet shaped car or for a brick wall shaped car? The 73 is actually kind of rounded in the front and has nice airflow over the top and back. more than a 55 chevy or some such.

 

If you want to go quick with that car you have two options assuming you want to keep a Buick powerplant in there:

1. Boost the 350, even a stock 350 under boost is a monster
2. Swap to a 455

 

https://www.hagerty.com/articles-vid.../13/horsepower


A comment below the article makes a relevant observation:

"I am a Professional Engine builder by trade and I have done a Ton of Engine dyno then chassis dyno comparrisons(sic). Older auto trannies, TH400,C6 typically show a 19-22% loss Older 4 speed manuals almost always show a 15-16% loss Newer AT cars, Camero(sic), firebird 12-15% New manual trans is 8-11% New auto 4x4 truck is 25-28% These are verified over 20 years of testing, so far I can tell if something is really wrong or if the hp claims were bs."