padam
Well-Known Member
Also I’m pretty clumsy.
Estimated 1/4 mile - 71 Roadrunner 340 4 speed
- Thread starter 340runner
- Start date
Talking stock style sliders and hubs. You can shift just about any manual without the clutch. If and a big if. You let up on the throttle and move the lever slowly shifting like my Grandma. On all out acceleration? Not a chance. Mines had all the sliders hand filed. Shifts very easily. However under heavy throttle you can pull on the lever as hard as you want. It won't move. That's the secret to fast shifting. Preload the shift lever. When you tap the clutch it'll come out of gear. By the time the lever starts moving the pedal can be released.
Doug
Doug
torredcuda
Well-Known Member
I usually started around 17-18 and never went below 15, it wasn't a huge improvement but it did help. The car was set up more for handling so track launches were hit and miss with the four speed.
340runner
Active Member
What do you mean by preload? Like holding to where it feels like it wants to pop out of the gate, and then slamming it home when you pop the clutch?
Yes try to pull hard on the lever during hard accelleration. It won't pull of gear unless you lift the throttle or hit the clutch.
Doug
Phantomx
Well-Known Member
It sounds like you need to learn how to drive this car without breaking it before you get too caught up in making it faster. You’ve smoked a 727, broken a diff, and several motor mounts. I don’t know if this car will live if you don’t learn how to keep it together. Just my thoughts.
Travis..
Travis..
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Motor is probably next to go if he keeps taching it up to 7k. Driving it like a video game.
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torredcuda
Well-Known Member
I used to power shift mine at the track with no issues, my old cam started making power at 3500 and I shifted at 7000 rpm and it was still pulling, but with the stock bottom end I was going over that.
340runner
Active Member
The 727 i smoked was on its way out... it didn't pull at all and was slipping. the motor mounts I'm honestly not sure if it's how I installed them because the first set lasted like 5 months then the second set was shitty autozone parts that lasted one day, then the poly mounts lasted like 2 months.
The diff I'm not sure why it broke cause the car can't hook and it didn't break on a launch but while I was already moving
340runner
Active Member
Yeah I don't get why 7k is that hard of a push for redline as it's a fully forged 71 340 with upgraded roller valvetrain and better flowing heads, exhaust, intake and better fueling system so it doesn't go lean. It also has a 8 qt oil pan so lack of oil isn't an issue
340runner
Active Member
Also explain, I'm not really trying to make it go faster via mods, I'm exactly trying to do that, learn how to actually drive it properly without damaging it. I can drive it and baby it, I daily a stick shift car I just want to figure out how to drive, shift and get a better et, street tire or slick
Curiousyellow71
Well-Known Member
I'd suggest getting a tire that will hook and then work on the engine so it works with the combination you have.
If it bogs now..getting traction will make that worse. I think you would find a holley vac secondary or a AVS2, or a thermoquad would pickup the load better when you dump the clutch. You could tune the double pumper, but it will be a struggle, and even when it's dialed in better, the other carbs are easier to tune, and likely faster over wider conditions. I am saying that and I have 5 double pumpers on various cars, none are 4 speeds. On our 340 4 speed we run a thermoquad.
If it bogs now..getting traction will make that worse. I think you would find a holley vac secondary or a AVS2, or a thermoquad would pickup the load better when you dump the clutch. You could tune the double pumper, but it will be a struggle, and even when it's dialed in better, the other carbs are easier to tune, and likely faster over wider conditions. I am saying that and I have 5 double pumpers on various cars, none are 4 speeds. On our 340 4 speed we run a thermoquad.
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340runner
Active Member
Well, when you say bog I mean when i start spinning and I let off, I don't think it's a car issue but a issue between the wheel and the seat to where I need to learn to feather the throttle and ease on and off and not just let go of the gas pedal like its searing hot. I can break them loose decently well, and I can ride the spinning of my tires out and eventually i gain traction again without it bogging. Ihad the carb tuned with help from a friend since i dont know a god damn thing about carbs outside of a lawnmower. it idles nice and doesn't sound like it pings from leaning out at rpm.
I don't bog when I step on it from roll at really any rpm or speed, I hear the secondaries kick open and away I go.
My spark plugs are also in good condition, I really doubt it's a carb issue but if a thermoquad helps and I can find one at a reasonable price i may switch. I've heard they are hard to tune though
340runner
Active Member
Forgot to say, it also does not give off signs of valve float at rpm, there's still a Lil juice to give when i shift
I'm also leaving at around 3.5k, which isn't my peak tq or power, but it's to where it's kinda controllable, if I get stickier tires I could leave at higher rpm
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Curiousyellow71
Well-Known Member
If you got traction you would know what I am talking about. Breaking traction is helping the double pumper with a 4 speed. A double pumper is going to be a struggle. Just saying. Do research...double pumpers are great carbs. But a high geared 4 speed is a poor fit for one.
340runner
Active Member
Okay, so with the thermoquad, would you also recommend going from a single plane to a dual plane like the performer RPM or is the single plane going to match well. Also I'd have to use an adapter to go from square to spread bore.
With all this said, is the AVS the better choice?
Curiousyellow71
Well-Known Member
All the rpm air gaps are for a square bore like a holley or a avs. Although, I think a rpm would be a tenth or two faster in e.t. at the drag strip with 3.55s over what you have. I would start with what you have now. But, get some tires that hook first.
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340runner
Active Member
Will do, still got some time till I can actually break out the car from it's jail in the garage, still dead winter over here. Like the video I posted in an earlier page was from August, I don't know how just from driving stick for another half year and learning more hand to foot coordination will help me improve ET just through quicker shifts.
I'm just planning ahead early, it's getting boring not doing anything really and seeing what I will want to prioritize with money first and if that thing is really nothing and just learning to drive the car
Curiousyellow71
Well-Known Member
Your videos are great!
A "prepped" drag strip and a highway are 2 different animals for traction.
Our 72 satellite would've been lucky to have a 2.5 60' on the highway. At Heartland park topeka it had a 1.99 60'..with a 215-70r14 off a grandma car.
At another time we switched a thermoquad with a 850 race dp at the track... back to back. No difference in e.t., both were 11.0@121mph. We spent lots of time getting the holley so it ran that good. The thermoquad..we did nothing to it and went as fast. Thermoquad have their quirks though, they are getting old. Lol
A "prepped" drag strip and a highway are 2 different animals for traction.
Our 72 satellite would've been lucky to have a 2.5 60' on the highway. At Heartland park topeka it had a 1.99 60'..with a 215-70r14 off a grandma car.
At another time we switched a thermoquad with a 850 race dp at the track... back to back. No difference in e.t., both were 11.0@121mph. We spent lots of time getting the holley so it ran that good. The thermoquad..we did nothing to it and went as fast. Thermoquad have their quirks though, they are getting old. Lol
66 Sat
Well-Known Member
If you want to go faster in the quarter mile I wouldn't be swapping out the double pumper for an AVS (or a thermoquad). Spend your money elsewhere as suggested, your carb isn't holding you back.
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