Lime Green 71OLDS 442 convertible

[71OLDS]

Four ten gears might be fun, but there is a significant increase in driveshaft speed, which can definitely cause some driveline vibrations. I don't know your exact tire size, but I suspect the driveshaft will be spinning close to 4000RPM at 75mph, which is pretty fast...

Andrew

Hi Andrew - running almost 29" rear tires (Nitto 305 45 18 drag radials) I chose the 4.10 for several reasons. I had it all broken down in an earlier post but pasted it below again. Bottom line is our 4000 lbs cars like a launch factor of between 10-11 for the least amount of spin/bog plus at my shift point of around 6000 RPM the #s work great for 1/8 mile and 1/4 mile to be in a good RPM range when I cross the traps. Last is the hwy RPMs as shown. Honestly I'm not worried about the driveshaft RPM as long as there's no vibration. Driveshaft comes with the American Powertrain kit with the 6 speed and seems like a high end piece so I would be really surprised if there are any issues. I will certainly update on this thread if so with all results good or bad.



Here's what the #s will look like with the new trans and rear:

Magnum TR6060 6 speed (2.66, 1.78,1.30,1.00, .8, .63)

W: 4.10 gears & 305/45/18 Nitto DRs:

{28.78” tire}
1st = 4.10*2.66= 10.91 launch multiplier/ 2nd =4.10* 1.78 = 7.30 /3rd =4.10*1.30=5.33 4th =4.10*1.00=4.10
Shift points:
1-2 47 mph 6000 RPM (RPM drop to 4000 67%)
2-3 70 mph 6000 RPM (RPM drop to 4400 73%)
3-4 96 mph 1/8th mile 6000 RPM (RPM drop to 4600 77%)
Cross traps for 1/4 mile at approx.: 117 mph = 5600 RPM (in 4th gear) w/current motor
125 mph =6000 RPM (in 4th gear) - room to grow (future stroker motor 650/650)

POWER RANGE = 4000 – 6000 (2000 RPM Power band)

2300 RPM = 60 MPH in 5th and 76 mph in 6th
65 mph in 5th gear @ 2500 RPM (W/28.78”)
70 mph in 6th gear @ 2100 RPM (W/28.78”)
75 mph in 6th gear @ 2263 RPM (W/28.78”)
80 mph in 6th gear @ 2413 RPM (W/28.78”)
150 mph in 6th gear @ 4525 RPM (W/28.78”)

[71OLDS]

Lee 800 steering box and new chassis brace are on:

[71OLDS]

AFX spindles, steering arms, upper control arms, and GT rotors are installed:

[71OLDS]

Finally a little progress - 6 speed install is coming along - slowly but surely:





Oil cooler is installed:



Got the old Hooker SC 1 7/8 headers coated:

Switching back to my Holley 830 carb from the 770 street avenger:

[badolds]

Very nice car and build thread here. I appreciate your wheel and tire help in my thread.

Dan

[71OLDS]

Thanks Dan - right back at you and glad to help!

-Joe

[71OLDS]

Haven't posted in a while - almost ready to buy and try the "442" shifter handle. The nice thing is the Magnum 6 speed that came from American Powertrain lines up really close to fit the stock 4 speed console pretty well - at least from the "eye ball" test at this point. We'll see how much "tweaking" is needed when we get that far along.

One of the latest challenges have been with the new hydraulic clutch setup - mostly because of my clutch pedal. Long story but once the hydraulic clutch was set up to spec per American Powertrain, the clutch pedal was way too hard. Apparently the spec for a stock 68-72 GM A body didn't work for my car. But....it turns out I may not have a "stock" clutch pedal. At any rate after lots of tweaking I think it's finally dialed in as it should be.

The other issue is the oil cooler. The oil filter relocater had to be moved from being horizontal to vertical - with it horizontal it wouldn't catch the oil from the filter. With it vertical it will catch the oil and not make a huge mess!!

Hoping to start on the roll bar next week - huge custom project for it with my shoulder harness belts and everything else on my "wish list" that I mocked up with the pvc pipes. Frank and team have their work cut out for them on this project. - will add pics when I have some.

[Jeff70]

Sorry if I missed it but what clutch set up did you go with? Are you using a reproduction console?


Jeff

[71OLDS]

Sorry if I missed it but what clutch set up did you go with? Are you using a reproduction console?


Jeff

Actually I don't think I ever posted it. Looked at the powertrain and McLeod Hyd clutch kits - went with the powertrain. I figured it would be easier to only have one place to use for support for both the trans and clutch. If anything didn't work together they couldn't blame it on the other company. Here's the link with pics, details, and even a video: http://americanpowertrain.com/i-8521...viper-t56.html

Going with the stock 4 speed console.

[71OLDS]

A few new updates and pics. First I was worried the new 600 lb front springs wouldn't let the car lower down enough in the front where I like it. Happy to see it's now "settled" back down:



Hyd clutch and clutch pedal issues are much better now. Clutch pedal is not as "soft" as I hoped it would be but a little softer then the manual, Z bar set up. Plus it is consistent from the floor to release which I like. Was able to shift through the gears and I'm blown away with how short and crisp it is from gear to gear vs. my Richmond 5 speed. Can't wait to drive the car. Still waiting on the custom metal piece to go over the top of the trans in the interior to be finished. Here's a pic of the hyd clutch reservoir and the trans from inside the car with the Big F'ng hole cut out:



I hate the shifter handle that came with the American Powertrain kit. Can't wait to swap it out for this one:

[71OLDS]

The oil filter relocater has been moved from horizontal:



to vertical:

[71OLDS]

The chromoly tubing has been ordered for the roll bar. Decided to add 2 small angled bars from the main hoop down to the floor board for some additional support. Will still allow back seat passengers even with these installed but it might be against the outside of the rear passenger's calf. Frank has it on one of his cars so you can see what I'm referring to:

passenger side:



driver's side:



Crude drawing but shows design of roll bar. White areas will be removable:



door bars will be similar to this old Joe Mondello car - that big bend allows it to pass between shoulder and elbow but also as you can just barely see on the drivers door you don't have to move or modify the arm rests:

[71OLDS]

slowly but surely transferring all my photobucket pics over to a new 3rd party host site. What a frustrating waste of time. Can't believe photobucket went from zero to $400/year to host pics. For that much it's totally worth my time to switch all my pics - hundreds of them!! Oh well.

In the meantime - here's a new update I'm sure most could care less about but I'm pretty excited. I had gone with the fiberglass decklid years ago but even with the wing mounted, it's still so light that when you open the trunk it "flies" open way too fast and seems like it could rip right off the hinges. Also I have the factory power trunk button in the glove box but couldn't use it anymore...for the same reason....plus I have a key fab alarm system that COULD have the power trunk added but couldn't do any of this with the super light glass decklid. The only option was to add some type of "shock" to make the trunk open slowly. Additionally I have a requirement to be able to fit my golf bag in the trunk so any shocks that were added couldn't block the space. So...here's the end result. Really happy with this. You have to look close to see the 2 shock mounts on either side. Next the factory power trunk button in the trunk will be hooked back up and will have the power trunk added on the key fab.


https://www.youtube.com/watch?v=B5iHM-Ujx7I

The trunk is fully enclosed and nicely done when the enclosure pieces are "installed". Everything is removed now so the sub, battery amps etc are all exposed. Will have to notch the enclosure pieces in 2 places to accommodate the new shocks but will look nice and clean again when it's all done.

close up pic of one of the shocks to show how and where it was installed:

[71OLDS]

Having a front spoiler similar to this one installed:





I got the glass part years ago with the glass front bumper but need it secured/supported for speeds up to 150 mph. Frank and team are working on a plan to get it squared away.

[Mr Nick]

Your images are not working for me.

[deejai35]

I like the trunk action. I hadn't thought about the weight savings there. I would love to replace the hood and trunk with carbon fiber, but I haven't found any available. I did research a company at one point that would produce a hood based on an example. I believe the minimum order was 10 units and price was between $1000 to $1500 each.

[71OLDS]

I like the trunk action. I hadn't thought about the weight savings there. I would love to replace the hood and trunk with carbon fiber, but I haven't found any available. I did research a company at one point that would produce a hood based on an example. I believe the minimum order was 10 units and price was between $1000 to $1500 each.

I'm sure Carbon Fiber parts would be lighter and stronger than the fiberglass parts but I'm guessing they will be more expensive and not sure how painting them would turn out.....but for me I have a long way to go to get these glass parts how I want. Slowly but surely getting things how I want.

Your images are not working for me.

Hi Nick - yeah pics were down with the new snapchat hosting company I used - not sure why but they appear to be back now. Hopefully it stays that way but we'll see.

-Joe

[71OLDS]

New tunnel is getting there:

[71OLDS]

Looks like console is going to work without any serious mods. Really happy about that!!

[71OLDS]

The new UMI rear sway bar that works with the relocation brackets (part #4012) is now installed. The sway bar is Part #: 4047-XXX - this is the 1" pro tour chassis mounted bar. The standard Hothkis bar hung way too low with the relocation brackets so I had to move to a chassis mounted one. A nice feature with this bar is it's adjustable - choose the "longest" hole for street, middle hole for auto-x, road race and the shortest hole for drag use.




Here's a close up of the relocation bracket - you can see where the old Hotchkis bar mounted:


...and you can see here how far down the old bar hung-just not going to work - had to switch the a chassis mount bar: