How to tell if trans cutout for 4spd is authentic

[Michael4yah]

How to tell if trans cutout is authentic? Is it possible to take an original auto trans tunnel and cut out for 4spd and make it look original? Is there a pattern that is a dead giveaway for a 4spd? Is the floor tunnel shape the same for both? Also is there any 12 bolt ratios that were used exclusively for 4spds or 400s?

[bigchevydaddy]

What type and year of car are you referring to?

[Michael4yah]

THis is a 68 RSSS 396

[69SSRSL89]

I may be wrong but on the 69's the auto cars speedo cable came out of the firewall on the drivers side of the master cylinder and the manual came out behind the distibutor location. I would think if the auto speedo hole was there it most likely was an auto first. That's just my 2 cents. Hopefully that helps you out. Jesse

[Keith Tedford]

In the later seventies the 4 speed hole was cut out with a torch. Our Chevelles look the same. There was a copper guide laid on the floor pan to guide the torch. It sure looked home done so it shouldn't be too hard to duplicate. How you are going to spot weld the shifter box on over the hole could be a problem if you are looking for the original look.

[68SSCamaro]

I have a 68 Camaro 4 speed. In 68 the hole is only there for a manual transmission. It is cut or punched and there is a plate welded for mounting the shifter boot and plate. Automatics used a cable. They had a small hole for the cable feed-thru. Also if you have a SS 4-speed it would be a Muncie and the speedo cable is located differently. Study the Assembly Manual.

[Hylton]

Martin is bang on. Look for the support plate underneath the hole. You should be able to see the bracket by looking underneath your car even if the tranny is in it. This support plate is currently not reproduced so should be a tell tale sign.

[Michael4yah]

Does anyone know if 12 bolt ratios were different for 4spds?How about driveshafts or yokes? Thanks to everyone for the help. Michael

[firstgenaddict]

Although most 68 auto's did use a cable... there were a few TH400 floor shift with out console cars made.
They used the 67 style auto shifter with the hole cut in the floor.
It was option M11, they are quite rare.
I had a 68 RS/SS 396 325 that had the option.
Sold the car to Maryland in the early 90's.
KurtS told me that he has only heard of about 3 of them and I believe only has only seen 1.
I have the VIN of my old car if you think it may be it. It was Lemans Blue with Blue deluxe interior... in the early 90's it had 43k miles and was matching numbers.

[Hylton]

[ QUOTE ]
Does anyone know if 12 bolt ratios were different for 4spds?How about driveshafts or yokes? Thanks to everyone for the help. Michael

[/ QUOTE ]

Gear ratios were an option which means that someone could have ordered the car with anything regardless of whether the car came with an auto or stick. Having said that, the auto. cars generally had a lower gear ratio than the stick cars. 3.08 gears were common for both auto and 4-spd in 67 and 68 small block cars.