Best way to get a better holeshot????

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Joined
Dec 21, 2013
Messages
356
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Location
Brier, Washington
My Car
1972 Fastback (Factory sprint, but now a bright red Mach 1)
351c 2v(big ol cam, holley dominator intake, roller set, edelbrock 4bbl)

fmx
HEY HOTRODDERS!

Ive got a 72 fastback with some modest engine mods:

Mild comp cam

Comp roller rockers

Singleplane holley street dominator intake

edelbrock 4 bbl carb

Headers and magnaflow exhaust

(Not sure how much hp it makes. My dad says maybe around 300)

It runs a stock FMX and has 2:75:1 gears in the back.

Im trying to get it off the line faster!

ANY SUGGESTIONS?? (im only 16 and im paying for this whole car myself so money matters)

thanks!!

 
Gears forsure. i went from a 2.75 to a 3.89 and it was a world of difference! a little stall converter would help as well.

 
Rear end gears, a 3.50 or so will allow the car to accelerate better. Pay attention in math class and learn about mechanical advantage. Making a car go fast is simple physics and math.
I agree 100% - swapping gears will probably get you the result you want easier than any other. Replacing my 2.75 gears for 3.50 with TrakLock turned the 'vert into a different car off the line. And I did it without having to refer to my Math/Science teaching background. :p And droptop73 is absolutely right about paying attention in those classes if you want to know the reason why the change in rear end resulted in better hole shot performance. :cool:

Have fun and stay in school!

 
if it is an 8 inch rear end a 3.40 gear is available . I ran in a similarly equipped coupe back in the late 80's and it was still able to take the interstate for long trips without getting bad mileage, 16-17 all day long. Very snappy, but doesn't overload your tires traction too much either.

 
Thanks guys! Will freeway driving be possible without running over 3000 rpm? (sayy with 3.40s or something)

Also, any pointers on how to get into the pumpkin? in or out of car? Procedure? I havent messed around with any of that yet.

Thanks for the help!!

 
There are tons of online calculators about finding gear ratios an rpms. I like to use the summit version http://www.summitracing.com/expertadviceandnews/calcsandtools/gear-ratio-calculator

Just plug in tire size an desired gear ratio and you can find what rpms you'll most likely be at.

To pull out a pumpkin you have to

Jack car up

Pull tires off

Pull axles out

Disconnect drive shaft from the pumpkin

Unbolt the pumpkin and make sure you have a drain pan nearby

 
Higher gears is the simplest way to get off the line quicker, but without an overdrive, your RPMs at highway speed will go up. What is your RPM at 70MPH now? Probably in the high 2,000s?

 
What kind of ratio would you recommend to increase acceleration, but without compromising the ability to blow by the pruis in front of me (on the freeway)

thanks!

 
What kind of ratio would you recommend to increase acceleration, but without compromising the ability to blow by the pruis in front of me (on the freeway)

thanks!
3.0 range or 3.25 tops. I run 3.5 and can tell you that 80mph is about 3800 RPM. That's a lot. A pruis can do 80 easy. I see them hauling down the freeway all of the time.

 
HEY HOTRODDERS!

Ive got a 72 fastback with some modest engine mods:

Mild comp cam

Comp roller rockers

Singleplane holley street dominator intake

edelbrock 4 bbl carb

Headers and magnaflow exhaust

(Not sure how much hp it makes. My dad says maybe around 300)

It runs a stock FMX and has 2:75:1 gears in the back.

Im trying to get it off the line faster!

ANY SUGGESTIONS?? (im only 16 and im paying for this whole car myself so money matters)

thanks!!
Of course you are talking about racing only on a NHRA sponsored track?

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(Old man time) (in the voice of Clint Eastwood):

In my day if you got caught street racing they chewed your butt, called your parents, and sent you home. Sometimes you would get a ticket and the Judge would chew your butt, call your parents, and send you home.

Now they can and quite often take your car, take your license, fine your butt until you have no butt left, call your insurance carrier who flags your butt so when you get you license back they can charge you until you have no butt left. The parents get called last.

Hurts or kill someone street racing and you are a felon - that will change your future.

Its not fair but that is what they do.

(Clint has left the building)

 
Last edited by a moderator:
Whoa! He didn't say he wanted to street race, he just said he wanted more umph off the line. Who doesn't? I like the feel of some G's when I get on it a little. Heck, higher gears means less speed right?

BTW, reread the OP. Get rid of the single plane, it's no good for the street.

 
Look i aint no street racer. I put every dollar i had and then some into this car, theres no way i'd risk it racing some asshole. PLUS, I cant afford to drive like that, one speeding ticket and WHAM no more licence. In case you didnt know, Brier washington is speeding ticket alley!! My buddy Trey got pulled over on new years eve for being suspicious, he was going 25 mph!:dodgy:

I dont think im Parnelli Jones, who am i kidding? all i want is better acceleration! Who doesnt??:D

 
Look i aint no street racer. I put every dollar i had and then some into this car, theres no way i'd risk it racing some asshole. PLUS, I cant afford to drive like that, one speeding ticket and WHAM no more licence. In case you didnt know, Brier washington is speeding ticket alley!! My buddy Trey got pulled over on new years eve for being suspicious, he was going 25 mph!:dodgy:

I dont think im Parnelli Jones, who am i kidding? all i want is better acceleration! Who doesnt??:D
29yfmo4.jpg


 
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