Best 5 speed conversion
Burning Brakes
Joined: Oct 2009
Posts: 1,066
Likes: 57
Say if a motor is "happy" cruising at 2400 rpm due to the cam then lugging it at 1800 wont do you a bit of good.
Lower rpm does not always equal better.
Ex -DD 02 Silverado, stock 3.73 gear, 4.60e gets the same mileage at 60 in D as it does in OD. So 65 up OD is a plus, on the st it just lugs the motor.
If you got a big cam OD is useless unless youre really humming. 6th gear in my A body, unless Im doing 80plus isnt needed period.
Lower rpm does not always equal better.
Ex -DD 02 Silverado, stock 3.73 gear, 4.60e gets the same mileage at 60 in D as it does in OD. So 65 up OD is a plus, on the st it just lugs the motor.
If you got a big cam OD is useless unless youre really humming. 6th gear in my A body, unless Im doing 80plus isnt needed period.
Thanks
Race Director
Joined: Mar 2016
Posts: 14,399
Likes: 8,204
From: Napa Valley California
If you have a camshaft with an operating range of 2000-6000 rpm and your trans and rear end gearing combination sets your cruising rpm at 1700 at 70 mph you are outside the power band and you will be lugging down the road.
Modern cars with computer adjusted timing and fuel mixtures can work under these conditions but our older motors especially if you are running a carburetor aren't too happy.
You may find that you are down shifting at every slight grade to keep the rpm's up to a happy speed.
Another thing to consider is with a .64 5th gear and a 1.0 4th gear, when you do down shift from 5th to 4th your rpm's will increase around 900 rpm.
Plan your entire build including your bore, stroke, CR, heads, camshaft, trans, and rear end gearing to all work together for your intended use of your car.
Building a high revving motor with a peak horsepower over 6000 rpm for street use is a waste, but at the drag strip it's a totally different story.
A street motor with good mid range torque and horsepower operating within it's power band will be much more fun to drive.
Modern cars with computer adjusted timing and fuel mixtures can work under these conditions but our older motors especially if you are running a carburetor aren't too happy.
You may find that you are down shifting at every slight grade to keep the rpm's up to a happy speed.
Another thing to consider is with a .64 5th gear and a 1.0 4th gear, when you do down shift from 5th to 4th your rpm's will increase around 900 rpm.
Plan your entire build including your bore, stroke, CR, heads, camshaft, trans, and rear end gearing to all work together for your intended use of your car.
Building a high revving motor with a peak horsepower over 6000 rpm for street use is a waste, but at the drag strip it's a totally different story.
A street motor with good mid range torque and horsepower operating within it's power band will be much more fun to drive.
Race Director
Joined: Mar 2016
Posts: 14,399
Likes: 8,204
From: Napa Valley California
Burning Brakes
Joined: May 2017
Posts: 774
Likes: 375
From: Seattle WA
SST is fantastic. I got the TKO600 Perfect Fit kit from them and converted over to a hydraulic pedal based on their recommendation. They are awesome and I love the system.
Race Director
Joined: Mar 2016
Posts: 14,399
Likes: 8,204
From: Napa Valley California
I have had great responses to all my questions setting up a kit that will work perfect in my C3.
