Hello everyone, I am confused? I am converting my chevelle to a manual trans and I see 2 different 4 speed humps one with a console and one without.. The last time I did this type of swap over (a very long time ago) I just remember and outline of a hole stamped in the floor sound deadener, So I cut the hole out and everything worked fine. I find it hard to believe that they make 3 different floors for these cars on the assembly line; I could see some additional brackets but a completely different floor?? Any input from all the knowledge on this website would be greatly appreciated..

Thanks everyone.......Dazed and confused :)

The shifter tunnel is a separate sheet metal piece that gets welded on depending on the application. It sits on top of the tranny tunnel. The tranny tunnel and the rest of the floor doesn't change from car to car.

The floors were all the same. Then if they had a floor shift it would be cut out and different humps were welded in depending on whether it had a (4/3 speed/auto) console or not.

Thanks for clearing up the puzzle for me, I double checked my assembly manual thinking i missed something but i still didnt see anything that shows that step of the build, Thanks again for filling in the blank in the manual, no surprise manufactures always seem to leave something out :)

Do a search on transmission hump. This topic was just covered last week in detail. There were some picturers posted that will help you a lot.

Here is my response to a similar question a while ago. Hope it helps


Yes it will (I had a GrandPA's 70 with a 350/TH350 column and now it has an M22 floor shift with bench seats). I stayed with the bench seats because I like the look (call me weird). I'll dig up some photos.

You will need:
1. Shifter boot
2. Shifter boot retainer ring kit
3. Shift tunnel extension
4. The CORRECT shift handle. If you are getting a Hurst...make sure it's the right handle or you will have problems!!
5. A pedal conversion kit (I think NPD sells them) or a set of originals
6. Obviously the clutch and linkage (zbar, block ball, fork, etc)
7. PATIENCE
8. Remember: Measure TWICE, cut ONCE!

It is a fairly straightforward (but time consuming) project. This will most likely NOT be a one weekend project if you have never done this before.

To find where to make the cut in the transtunnel:
- Mount the new tranny with the shifter attatched (but NOT with the handle attatched .... duh :)).
- Make sure everything is torqued down and in place especially the trans support.
- You COULD use the old transmount from the TH350 but I would just buy a new one. I made the mistake of cheaping out and keeping the old one. When I installed a new one this year I found that I had to cut a bit more from the transtunnel for clearance. Just buy a new one and avoid that.
- Once you get everything torqued down, reach up with a long screwdriver and make a mark directly above the shift handle mount on the shifter (that will be your reference point for the shift tunnel extension).
- Now....remove the tranny (If you are lucky, you MAY be able to get away with just taking off the shifter).
- Remove your front seat and carpet.
- Drill a hole in the floor using your reference point.
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A WORD OF CAUTION: I 'eyeballed' the rest of my installation. I'm sure there are better ways to do this but I've never been accused of doing things the 'easy way' :). You just need to use common sense and make the smallest cuts possible. I removed VERY LITTLE sheetmetal to make this work. Theoretically you could mount the TransTunnel extension centered over your reference hole and cut the rest of the sheetmetal out. THIS GIVES YOU NO ROOM FOR ERROR or differences in the size of future mounts...etc. The best bet is to cut as little as possible until it fits. You can always make adjustments later.
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- Clear out enough metal so that the shifter handle MOUNT (not the whole shifter) will slide through.
- Re-install the shifter and handle
- Make sure that you have removed enough metal so that you can row through all of the gears without hitting the trans-tunnel. It is especailly important to make sure that you have at LEAST 1/4 inch of clearance on all sides of the shift handle and SHIFTER to allow for engine/tranny 'torque turn'.
- Take your transtunnel extension (the 'hump') and try to center it over the hole you just made. It will be apparent how the extension should sit on the tunnel but you will most likely have to make some adjustments to it. Keep in mind...the extension can look a bit rough when done but it will be 'hidden' by your carpeting and sound deadening material when finished.
- Once you find the best spot for extension...tape it down as securely as possible.
- Remove the Shifter and/or tranny
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At this point you have to make a decision as to how you want to mount your tunnel extension. You can weld it in or you can use rivets. I chose rivets because I can't weld to save my life and also because rivets are a lot easier to remove :) I used about 8-10 rivets and that extension isn't going to move anytime soon!
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- Mark your drill points on the extension with a punch
- Depending on your confidence with a drill...either drill straight through the extension and the tunnel or drill the holes in the extension first and then use that as a template to drill the holes in the tunnel. Either way works.
- MAKE SURE YOU USE THE CORRECT SIZE BIT!!! I used a medium sized rivet (can't remember the size). The box of rivets I purchased had a drill bit guide that told you what size bit to use.
- You will need to use something to seal the connection between the transtunnel and the extension. I used some silicone but that is up to you.
- Now just add rivets!

The rest is much easier and really doesn't need explaining. If you have any questions feel free to ask me (I believe I have a bunch of pictures too).

I did this without ANY prior mechanical experience (besides your light mechanical stuff like brakes, oil, belts and so forth) so you can do it too. Just take your time and ask questions if needed!

Oh Yeah....BUY A SERVICE MANUAL, FISHER BODY MANUAL, and an ASSEMBLY MANUAL!!! It will be the best $60-70 you will ever spend!

GOOD LUCK!

Do you really need the hump? Couldn't you just cut the hole and use the lower boot? Ralph

You definitely need a hump if it's a 70 because of the shape of the boot/bezel. Not sure about other years but I would guess that if you want it to look basically stock then the hump is probably the only way to go.

Thanks Malibu,

The step by step instructions is pretty much what I came up with to but it is nice to have reassurance before cutting up your floor !!! I think my biggest concern is the trans hump itself 2 different ones and the big question was do I really need one but I think my questions have been answered

Thanks everyone :)

Oh Yeah By the way Malibu I do have the Body manual / assy manual and service manual unless I am blind I could not find any information on trans humps please if its there let me know I sometimes look past things the 1st or 2cd time but the third i might be lossing it..... Thanks again for the info
Tom :)

Just a quick point... you probably already know...

There is a different carpet for MT versus AT to accomodate the shifter hump/extention. Your carpet may conform or may not...

Thanks for the heads up but I am not even close for carpet yet !!!!!!!!!!!
Still have a long way to go but cant wait till next spring I hope to be done by then :)

htm: Sorry I didn't respond sooner (LOST and OVER THERE was on and I can't miss those :) )

Anyway.....the instructions I quoted was from a message that I posted in another thread (I just cut/pasted the whole message). It wasn't directed at you. I was just too lazy to edit out the extra stuff :)

I know one of the manuals (can't remember which) has a picture/diagram of a 'generic' tunnel hump but I don't think it had anything specific.

The difference between the two humps is one is for use with a Console and the other is for use without a console.

Believe it or not....the toughest part of the entire switch was getting the screws for the Bezel to match up with the holes I drilled in the hump. Took some time and patience but eventually they went in.

Good luck!

PS: Make sure you read the quote in my sig before you start :)

I think you mis-took my reply,, no need to apoligize for anything I appricate you taking the time out to assit me in my project sorry if I came off wrong did not mean to.. Thanks again for your help
Tom

I didn't know there was a different carpet made for Chevelles equipped wiith a 4-spd or auto transmision. When I ordered mine, there was no distinction between the two. Fit OK with my console equipped 4-speed tranny.

No problem at all htm. In this day and age of words and no voice, I just wanted to make sure you didn't think I was 'talking down' to you :)

If you run into any problems during your 'project' let us know!

Right back at you, I never took it that way thanks for the offer of guidance I am sure I will calling on this fourm again,,,,, and by the way nice ride you have there :)

Man, I've been wanting to post on this for a couple of days but I have been having problems with my account. ANYHOW... On a '66 and '67, the are NO differences between the console and non-console 4-speed humps. The resto places have their wires crossed. This was just covered in Restoration Corner about a week or two ago. Hope that helps.

Steve

hey guys,just wondering is there already a hole in the frame to convert over have a 1972 chevelle. thanks for comments.

Thanks Danny.

hey guys,just wondering is there already a hole in the frame to convert over have a 1972 chevelle. thanks for comments.

Thanks Danny.

A hole in the frame for what???????????