slugish sbc 350

[truracer20]

Your trans should downshift to 3rd when you step on it. You can manually downshift to 3rd. But the real issue is the gear ratio. What are your RPMs in OD at 65 MPH? My car with a similar engine has 2.73 gears and no OD, at 65 MPH I'm turning 2400 RPM. I'll bet in OD you are around 1300 RPM. You really need more gear. A 3.73 would give you about 2200 RPM at 65 in OD and 3300 in 3rd. 4.11 would be around 2500 RPM at 65 in OD and 3700 in 3rd. This all assumes a 26" tire. The RPM calculator on this page should help you out, http://www.differentials.com/technical- ... calculator
You really should look into why your trans isn't downshifting.

 

[spidereyes455]

Mismatch between the cam's operating range and your rear gear is most likley why it feels dead in OD. With the .70 OD ratio in a 700 and a 2.29 rear gear that makes your effective gear ratio equivilent to a 1.60 , assuming a 26 inch tall tire that puts you at about 1350 rpm at 65 mph in 4th while you'd still be under 2000 in 3rd at the same speed. IMO thats much too high of a ratio for a chevy especially with a larger than stock cam. Chevys need to rev more than the BOP engines to be effective and efficient at the same road speed , thats why most of the chevy powered cars of the era witout OD had slightly lower ratios commonly 2.73 vs 2.41, 2.29 or even 2.14 for the BOP powered cars but still had similar fuel mileage. Also it is important to remember that OD is designed for cruising at stable highway speeds under light throttle conditions not for passing traffic at full throttle.

 

[oldmansmonte]

The gears will make the car feel underpowered, but that should go away on the highway. My Monte has 2:73's and my Caprice has 2:56's.


Sounds like your torque converter is not unlocking and or your transmission cable is not adjusted properly. How does it shift under other driving conditions?

 

[bleedchevy]

Wow thanks guys for the input... I will be swapping out the gears soon.. here's a quick spec of my build.Intake:
Edelbrock Performer RPM
Bearings: King Alecular High Performance
Camshaft: Comp Cams - .510 Lift/224 Duration
Pistons: Sealed Power - Flat Top Hypereutecic
Rings: Federal Mogul - Moly
Compression Ratio: 10:1

 

[bleedchevy]

is your torque converter unlocking? do you have that hooked up?

Yes its wired up.

 

[bleedchevy]

Car shifts fine guys I'm reaching all of my gears. Let me find the specs on the converter I purchased...

 

[bleedchevy]

That rear end definitely isn't helping you. Is your throttle cable adjusted properly?? - the car should downshift at highway speeds when you get on the gas. Also unsure of what HP crate motor you have but you are probably running under the RPM range of the cam along with a stock converter and large head runners it will be sluggish. Does the engine come to life around 3000 rpm???

Yes its adjusted propley. I do believe the trans downshifts on highway, and that sounds about right 3000 she seems to wake up.

 

[bleedchevy]

This is my currwnt spec on the converter. 2200 - 2500 high stall GM Chevy Torque Converter - 4L60 4L60E 700R4 700 Lockup
Are yiu saying when in 4 gear and i step on the gas my converter shud be unlocking? Is that my passing gear not sure how it all works can someone explain. I currently have my convert wired to my ignition so when turn the key its on,could this be a issue.

Your trans should downshift to 3rd when you step on it. You can manually downshift to 3rd. But the real issue is the gear ratio. What are your RPMs in OD at 65 MPH? My car with a similar engine has 2.73 gears and no OD, at 65 MPH I'm turning 2400 RPM. I'll bet in OD you are around 1300 RPM. You really need more gear. A 3.73 would give you about 2200 RPM at 65 in OD and 3300 in 3rd. 4.11 would be around 2500 RPM at 65 in OD and 3700 in 3rd. This all assumes a 26" tire. The RPM calculator on this page should help you out, http://www.differentials.com/technical- ... calculator
You really should look into why your trans isn't downshifting.

 

[lilbowtie]

I currently have my convert wired to my ignition so when turn the key its on, could this be a issue.

BINGO !!!

 

[oldmansmonte]

This is my currwnt spec on the converter. 2200 - 2500 high stall GM Chevy Torque Converter - 4L60 4L60E 700R4 700 Lockup
Are yiu saying when in 4 gear and i step on the gas my converter shud be unlocking? Is that my passing gear not sure how it all works can someone explain. I currently have my convert wired to my ignition so when turn the key its on,could this be a issue.

Your trans should downshift to 3rd when you step on it. You can manually downshift to 3rd. But the real issue is the gear ratio. What are your RPMs in OD at 65 MPH? My car with a similar engine has 2.73 gears and no OD, at 65 MPH I'm turning 2400 RPM. I'll bet in OD you are around 1300 RPM. You really need more gear. A 3.73 would give you about 2200 RPM at 65 in OD and 3300 in 3rd. 4.11 would be around 2500 RPM at 65 in OD and 3700 in 3rd. This all assumes a 26" tire. The RPM calculator on this page should help you out, http://www.differentials.com/technical- ... calculator
You really should look into why your trans isn't downshifting.

You should really try hooking up a manual TC lockup switch(ridiculously easy). The nice thing about the manual switch is you can lock it up when you feel, not just above 55. Look at my thread link below. The diagram should be similar to your car and should be available online.

http://gbodyforum.com/viewtopic.php?f=1 ... FQ6yWenaAg