[ta man]

Originally Posted by Chief of the 60's

Besides "lugging", running with too low of RPM will cause the engine to load up and run hot. A higher RPM will allow for a cleaner burn resulting in cooler engine temperature. I have been dealing with O.D.'s in old cars for 20 years which, back then, people would say "they won't work" or "you can't do that". I have raced them as well as drove them on the street which is where I found what the sweet spot RPM is that makes everything happy.

Then what is the point of the expense of an overdrive if you wind up in the 2600 to 2800rpm range? That is 3.42 range with a th 350 or th400? One only has to tune the engine to run extended times at lower rpms with an overdrive.

[RocktimusPryme]

Originally Posted by ta man

Then what is the point of the expense of an overdrive if you wind up in the 2600 to 2800rpm range? That is 3.42 range with a th 350 or th400? One only has to tune the engine to run extended times at lower rpms with an overdrive.

I was thinking the same thing. I also thought the advantage of a lock-up converter was to eliminate the lugging at lower RPM.

Im pro OD, if my TH400 goes, Ill for sure build an 80e. But I wouldn't put in so much gear that I only bought myself a couple hundred RPM.

[JLMounce]

I can tell you that at least in my 69 bird, RPMs create a lot of heat. As I don't yet have my OD trans installed, with a 3.73 gear, 26" tall tire and a 1:1 final in the trans 65mph is about 3400 rpm. THe car runs a solid 20 degrees warmer in this condition than it does at 55mph where it's only running around 2800 rpm.

Additionally after such a drive, the power steering fluid has heat up quite a bit and until that cools back down the steering is a bit notchy and I will have lost about 1-2 lbs of idle oil pressure as the oil has heated up significantly.

I do think between 2000-2500 rpm is probably a pretty good area to be in for wherever your cruise at speed wise. One of the reasons I built a 60e instead of an 80e is because of the .7 OD instead of the .75. That helps make up for the fact I run a 26" tall tire.

[ron cozzo]

sjdiesel, I'm putting a 4l80e in the 66 LeMans I'm building. I'm using 3.55 gears. I have 3.73's in my 64 GTO with TKO600.

Any tips to share on fitting the 4l80e? I'm using the G-force c/mbr and the banjo cooling line fittings.

[sjdiesel]

Originally Posted by ron cozzo

sjdiesel, I'm putting a 4l80e in the 66 LeMans I'm building. I'm using 3.55 gears. I have 3.73's in my 64 GTO with TKO600.

Any tips to share on fitting the 4l80e? I'm using the G-force c/mbr and the banjo cooling line fittings.

The 4l80e was an easy install. I used the G-force cross member & banjo cooler fittings too. Those items are a MUST. I purchased some fittings and stainless tube, bent some short cooler line sections to attach to the trans and spliced into the th400 cooler lines. Came out really clean. No modifications to the floor are necessary to fit this trans in.
Here is a pic of it right after the install. I never got completed pics. Also I used the USShift controller which is awesome! I did use the TCI TPS since I had fabricated a TV mount on my throttle bracket.
I absolutely love the setup!!!

[PDC]

3.42 - 3.55 depending on converter should be plenty of gear on the street.
3.73 with the .75 OD is about as deep as I’d go for comfortable highway cruising. Which is obviously not a concern for a car that lives at the track (which really would just run with a TH400 if that was the case...)

[sjdiesel]

For how I drive this car, I’m leaning towards the 3.55’s. For the next few months I’m going to stick with the 3.23’s until I get the funds to do the gear swap. Also there is a couple things I have on the to do list first and like I said it’s not like the car is undriveable with the 3.23’s.
I have the factory BOP 10bolt in the car now. I believe Currie usually has a sale around thanksgiving so I might wait until then and upgrade to a Dana 60.

[Formulajones]

Originally Posted by RocktimusPryme

I was thinking the same thing. I also thought the advantage of a lock-up converter was to eliminate the lugging at lower RPM.

Im pro OD, if my TH400 goes, Ill for sure build an 80e. But I wouldn't put in so much gear that I only bought myself a couple hundred RPM.

I agree. the 80 doesn't offer a bunch of overdrive anyway, so a compromise is made on a street strip car.
Normally I stay a little on the conservative side. The 4.10's work nice at the track and have me at the finish line near peak, and since I've been driving the car for 35 years with a 400 turbo like this, a .75 overdrive will feel like a new lease on life. 75 mph will be 2800 rpm, which is a 20 mph improvement from the current setup. Been buzzing this thing at 2800 to 3,000 for decades to go 55-60 mph. 75 is enough that I can then make the 200 mile round trip to Phoenix no problem and keep up with traffic.
Maybe at some point I may drop the gear if I don't see myself going to the track as often in it.

But I get what you're saying. The car we drive the most, actually my wife more than me, uses a 3.55 with the .64 overdrive. 65 mph is 18-1900 and it's perfectly happy there. I can cruise 80 to phoenix and only turn 22-2300. Best part, it returns 22 mpg like that. Not bad for 780 carb that's a bit on the rich side.

[Formulas]

Not much mentioned about engine build or state of actual tune may be room for improvement there to make the engine happier at the lower RPMs

[ron cozzo]

sjdiesel, thanks for the info and pics. Super glad to here how well it fit with the right parts. I'm using the US-Shift Quick 4 also. I'm running a FI-Tech so TPS is just a wire tap away. What did you do for a dipstick tube?

[sjdiesel]

Originally Posted by ron cozzo

sjdiesel, thanks for the info and pics. Super glad to here how well it fit with the right parts. I'm using the US-Shift Quick 4 also. I'm running a FI-Tech so TPS is just a wire tap away. What did you do for a dipstick tube?

I used this dipstick and it fit perfectly.
https://www.summitracing.com/parts/SUM-702210

How do you like your FI tech? Fuel injection is high on my list. I’m looking at the Holley stealth setup because it can control the trans too. Probably should have done that first....

[sjdiesel]

Originally Posted by Formulas

Not much mentioned about engine build or state of actual tune may be room for improvement there to make the engine happier at the lower RPMs

There is a link to my engine build in my signature. Pretty standard Pontiac stroker build. 468 stroker, ported iron intake, ported 670 heads, 238/243 HR cam, Cliff Q-jet, MSD ignition.

Not sure what you mean by state of actual tune?

[ron cozzo]

Originally Posted by sjdiesel

How do you like your FI tech? Fuel injection is high on my list. I’m looking at the Holley stealth setup because it can control the trans too. Probably should have done that first....

Thanks for the dipstick info. It's too early to give an opinion on the FI Tech, I don't have it running in the car yet. It did make 470HP on my 406 on KRE's dyno.

[Murf]

Originally Posted by ron cozzo

Thanks for the dipstick info. It's too early to give an opinion on the FI Tech, I don't have it running in the car yet. It did make 470HP on my 406 on KRE's dyno.

Hi Ron, I sent you a PM.

Thanks
Murf


Sent from my iPhone using Tapatalk Pro

[ponjohn]

Maybe try unlocking the convertor in OD to see what difference it makes.

[Chief of the 60's]

Originally Posted by ponjohn

Maybe try unlocking the convertor in OD to see what difference it makes.

That is typically only about 200 RPM

[ponjohn]

Originally Posted by sjdiesel

The 4l80e was an easy install. I used the G-force cross member & banjo cooler fittings too. Those items are a MUST. I purchased some fittings and stainless tube, bent some short cooler line sections to attach to the trans and spliced into the th400 cooler lines. Came out really clean. No modifications to the floor are necessary to fit this trans in.
Here is a pic of it right after the install. I never got completed pics. Also I used the USShift controller which is awesome! I did use the TCI TPS since I had fabricated a TV mount on my throttle bracket.
I absolutely love the setup!!!

Where did you use the banjo bolts, at the trans fittings?

[Formulajones]

On the later model 80's they moved one of the cooler lines to the back of the trans housing. Was an improvement in oiling.

Problem becomes the case getting pretty close to the trans tunnel in that area, making it nearly impossible to bend a steel line to make the 90 degree turn into the case.

There are adapter fittings made that turns this into a banjo fitting similar to a disc brake caliper. Makes line install a snap.

[ron cozzo]

Here's one place to get the banjo cooling line fittings. https://www.ebay.com/itm/193546938631

[sjdiesel]

Originally Posted by ron cozzo

Here's one place to get the banjo cooling line fittings. https://www.ebay.com/itm/193546938631

This is what I used too. Worked perfectly. Nice thing is you can place them exactly where you want them.