Advise on which tunnel mod kit for LS3 w/T56 Magnum in 1st Gen?

[Nativefx]

Okay I've been searching all day on all the forums that i can think of trying to find a thread I remember reading a few weeks ago talking about the advantages of one of the tunnel mod kits. I'm going to swap in a T56 Magnum so I need to mod the tunnel for clearance. I know Speedtech and Chassisworks have pre-fabbed metal for this, I'm just looking for people's experience with either one?

If you have already modded your tunnel, did it also provide the necessary clearance for the bellhousing, or did you still need to massage the front of the tunnel for clearance? How much additional clearance do I need in order to fit the T56 magnum and get an optimum driveline angle? What kind of angle should I be shooting for?

thanks, Jake

[ADiCarlo]

I just went thru this. Let's start with the crossmember, have you purchased one or decided to fab your own?


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[Nativefx]

Hi AdiCarlo, no I have not purchased a crossmember yet. I figured the answer for the tunnel mod kit would lead to the correct crossmember? I was also hoping it would then lead to the right motor mounts to use.

FYI - I will be using a full length TMI center console, if that will matter for anything.

[ADiCarlo]

Ok that's great then! I would recommend a custom tunnel cap and crossmember similar to what Stielow or DSE is doing. I say this because to obtain the proper driveline angle your really going to have to tuck the transmission into the tunnel and I can't see a all for one cap truly being the solution.

Just FYI I purchased an off the shelve crossmember and ended up with 8 degrees of angle even when fully adjusted. We had to scrap that and make our own to get the needed 1 to 3 degree ratio we wanted.

I feel that because there are so many variations of engine mount set ups a lot of companies don't want to make crossmembers because there is too much variables in the mounts.

Here's our tunnel cut with a f body style trans mounted on a DSE subframe with DSE set back engine mounts:
https://www.flickr.com/gp/48011683@N07/Y83ii2


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[Nativefx]

Hmm so are Steinlow or DSE offering these custom caps and crossmembers? What crossmember did you end up using with your tunnel cap to get the driveline angle? Was it enough to clear the bellhousing as well? Are you using full size subframe mounts or half?

I've been reading through your build thread and see you are also using a Restomod Air AC system. I haven't read completely through yet, but did you end up with the Haymaker evap unit? If so, were you able to mount and space it away from the firewall so it doesn't hit the top portion of the tunnel? I need to figure out something because I'm mounting speakers in some Screamin Performance enclosures that will go in the kick panels. Right now due to the size of the evap unit, I don't think I'll have enough clearance unless I space it away from the firewall and then slide it towards the middle of the car a little more.

[ADiCarlo]

They make there own and are not for sale off the shelf. I would call DSE direct maybe they can make you a one off.

We ended up making our own similar to what Mark Stielow did but mounted it off the subframe where he did his off the body and reinforced the metal. This required us to raise the floor panels to get optimal clearance and tucking.


Check out this thread:
http://www.lateral-g.net/forums/showthread.php4?p=617961

We had to cut a little farther forward into the tunnel to get the best clearance for the bellhousing but this wasn't required.

We're using half inch body mounts.

Haven't fitted the haymaker yet but it shouldn't interfere with the tunnel. The kicker panels with speakers may be a different story. Once I mount I can try and take measurements.




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[Vega$69]

I used the Speedtech tunnel cover.

Worked perfect and it is for sale

My last car a fabbed my own cover. Cut the hole in the tunnel as required to position the tranny correctly, made a cardboard mock up and made the sheet metal cover.

Which is why I went with the Speedtech this time. I do have the Speedtech sub and X member.

[wiedemab]

Here is another option for you.

http://www.bbclassicsinc.com/products-page/fabrication-components/67-69-f-body-trans-tunnel-patch/

I talked to Billy last week and ended up ordering one for my '67 Chevy II project. I'm building the floors from scratch, but this is worth it in time savings. I'll post pics in my build thread once I get it.

[Nativefx]

I was hoping to be able to use a pre-formed tunnel cover, but I'm concerned about what actually works. It seems there are a number of factors that could come into play such as body mounts being used (full or half), stock subframe compared to aftermarket, space available for exhaust, correct motor mounts, etc. I'm using my stock subframe so I'm hoping I don't have to fab a one off. The main thing is if I have to cut the tunnel I want to make sure it will be sufficient to get the correct drive line angle. I haven't bought the x member or motor mounts yet so hopefully I can figure everything out and get the right parts that will work together on my stock sub.


I used the Speedtech tunnel cover.

Worked perfect and it is for sale

My last car a fabbed my own cover. Cut the hole in the tunnel as required to position the tranny correctly, made a cardboard mock up and made the sheet metal cover.

Which is why I went with the Speedtech this time. I do have the Speedtech sub and X member.

[Musclerodz]

Speedtech make a complete kit to make this a very simple deal.

[Nativefx]

I wasn't sure if their kit worked with a stock subframe or just one of theirs? I've also been looking for some other threads where people were discussing some of the issues with certain tunnel mods, but i can't figure out which forum I read this in and i don't remember which they had the best luck with once everything was finished. I don't mind modifying my tunnel, but I want to make sure I get the proper driveline angle.

Speedtech make a complete kit to make this a very simple deal.

[Vega$69]

With a stock sub you will need to

#1 Cut approx 8" wide by 20" long hole in the tunnel from about 3" behind the shifter. Then lift the tranny at the crossmember to the proper angle. Build a sheet metal box as needed to cover the hole and cut out the hole for the shifter.

#2 Raise the top of the tunnel by cutting the vertical sides just below the radius and once new height is determined weld in a strip of metal on each side and boxing the ends.

#3 Skip all the crap and buy a pre-made fabbed tunnel plate.

[jlwdvm]

The Hooker system of motor mounts and cross member were a breeze to install and I didn't have to make a single dimple to the tunnel and had 3 degrees of angle to my LS3- T56 after installation.

[Musclerodz]

I wasn't sure if their kit worked with a stock subframe or just one of theirs? I've also been looking for some other threads where people were discussing some of the issues with certain tunnel mods, but i can't figure out which forum I read this in and i don't remember which they had the best luck with once everything was finished. I don't mind modifying my tunnel, but I want to make sure I get the proper driveline angle.

Works with stock frame. Just installed their engine mounts and crossmember with a GTO 6 speed, no tunnel mods. If you have a Magnum you will have to use their tunnel box.

[randy]

i had to use the chassis works tunnel cap with my t56 magnum. If you are in this stage my opinion is to buy this for $100 and install it. I would rather have the extra room now just in case something changes in the future. Cheap insurance. The crossmember has nothing to do with tunnel clearance. Trans and engine angle and position all do. as far as shifter access goes buy brian finch billet shifter ring.
DSE subframe
ls3
t56 magnum
Car is very low

[Sieg]

Speedtech didn't have their cover on the market when I was installing my T56 Mag, I made my own cover that bolts in so I have access to the shifter if needed.....and I've needed it a couple times.

I would have bought the Speedtech unit in a heartbeat if it was available, though I would have modified it to have access to the shifter. :thumbsup:

[Nativefx]

Do you have a T56 Magnum, or a regular T56? I'm interested in looking at the Hooker system as well, but haven't been able to confirm if I can get the proper clearance and angle with their setup. If I remember right, the headers would also need to be modified to make room at the steering box? Not a deal breaker, but want to make sure I look at all my options.

thanks

The Hooker system of motor mounts and cross member were a breeze to install and I didn't have to make a single dimple to the tunnel and had 3 degrees of angle to my LS3- T56 after installation.

[Nativefx]

Haha, yeah Vega$69 I'm hoping to get confirmation I can go with #3 and get all the necessary components to go in correctly!

thanks for all your help!


With a stock sub you will need to

#1 Cut approx 8" wide by 20" long hole in the tunnel from about 3" behind the shifter. Then lift the tranny at the crossmember to the proper angle. Build a sheet metal box as needed to cover the hole and cut out the hole for the shifter.

#2 Raise the top of the tunnel by cutting the vertical sides just below the radius and once new height is determined weld in a strip of metal on each side and boxing the ends.

#3 Skip all the crap and buy a pre-made fabbed tunnel plate.

[Nativefx]

With their engine mounts and crossmember I'm assuming the pre-fabbed tunnel would work. Did you have any issues with getting the carpet to fit due to the shape of the tunnel cover? I have a one piece carpet kit to install once i'm ready. I've had someone tell me they had to send the x member back because it didn't provide the correct angle for his Magnum. My installation does include a T56 Magnum so i'm almost certain a tunnel mod is necessary.

Works with stock frame. Just installed their engine mounts and crossmember with a GTO 6 speed, no tunnel mods. If you have a Magnum you will have to use their tunnel box.

[Nativefx]

I'm almost certain with the Magnum I will need to modify the tunnel, which isn't a problem. How did you like the Chassisworks option and did everything go okay with installing it? What about getting your carpet to fit once it was installed? I realize the x member and engine mounts will dictate the driveline angle, but I want to make sure the correct tunnel mod is done to give me any room I need to adjust. From what i can tell, there are some differences in getting the right x member depending on the subframe your using?

thanks

i had to use the chassis works tunnel cap with my t56 magnum. If you are in this stage my opinion is to buy this for $100 and install it. I would rather have the extra room now just in case something changes in the future. Cheap insurance. The crossmember has nothing to do with tunnel clearance. Trans and engine angle and position all do. as far as shifter access goes buy brian finch billet shifter ring.
DSE subframe
ls3
t56 magnum
Car is very low

[Musclerodz]

With their engine mounts and crossmember I'm assuming the pre-fabbed tunnel would work. Did you have any issues with getting the carpet to fit due to the shape of the tunnel cover? I have a one piece carpet kit to install once i'm ready. I've had someone tell me they had to send the x member back because it didn't provide the correct angle for his Magnum. My installation does include a T56 Magnum so i'm almost certain a tunnel mod is necessary.

The tunnel box is fine, but would use something different if your not running a console. Its not designed to be pretty. They make 2 different crossmember heights so they may have sent the wrong one.

[randy]

I'm almost certain with the Magnum I will need to modify the tunnel, which isn't a problem. How did you like the Chassisworks option and did everything go okay with installing it? What about getting your carpet to fit once it was installed? I realize the x member and engine mounts will dictate the driveline angle, but I want to make sure the correct tunnel mod is done to give me any room I need to adjust. From what i can tell, there are some differences in getting the right x member depending on the subframe your using?

thanks

Chassisworks was amazing. Very smooth fantastic piece. Every car in the shop getting a t56 will now use that tunnel. We have already used 2 of them. we will be doing another one soon and I'm sure plenty more. Use any crossmember and then shim the transmission crossmember up to get the correct angle.

Want to know something that everyone here forgot to tell you? No matter what you do 9 times out of 10 everything will have to be modified in some way or the other. There is no 100% this way or that way. Every car is different. STOP and I repeat STOP overthinking it.

Spend the $100, get the tunnel, install the tunnel.

Crossmember isn't isn't with angle. Thats easy to fix. The issue is where your exhaust will come in contact with the crossmember based on the headers you are using and how close you want the exhaust to the floor.

Notice the clearance.
http://i30.photobucket.com/albums/c302/icemanrld19/12009787_10100678567437696_2645136611571591978_n.j pg (http://s30.photobucket.com/user/icemanrld19/media/12009787_10100678567437696_2645136611571591978_n.j pg.html)


crossmember surgeryhttp://i30.photobucket.com/albums/c302/icemanrld19/11846722_10100654819538676_6728932739520720605_n.j pg (http://s30.photobucket.com/user/icemanrld19/media/11846722_10100654819538676_6728932739520720605_n.j pg.html)
http://i30.photobucket.com/albums/c302/icemanrld19/11826069_10100653525995946_404240692632503258_n.jp g (http://s30.photobucket.com/user/icemanrld19/media/11826069_10100653525995946_404240692632503258_n.jp g.html)

the car. the shop also has a lsa 69, lsx376 magnuson, 572 69, and so on and so forth
http://i30.photobucket.com/albums/c302/icemanrld19/11231324_10100678567297976_387481630234051235_n.jp g (http://s30.photobucket.com/user/icemanrld19/media/11231324_10100678567297976_387481630234051235_n.jp g.html)

[Nativefx]

The tunnel box is fine, but would use something different if your not running a console. Its not designed to be pretty. They make 2 different crossmember heights so they may have sent the wrong one.

I'll have a TMI console I'll be installing, but one thing I noticed is it's not as wide as my factory console. I was wondering if they had different heights, but couldn't find anything on their site. I'll have to see if I can get the measurements and make sure it will cover. thanks for the info!

[Nativefx]

I hear what your saying Randy, I know I'll have to mod the tunnel. I'm sure we will have to mod something else as well which is why I'm trying to get as much info as possible before i go out and buy parts that won't work or will take significant modification to work. Your point about where the headers/exhaust will come into contact with the crossmember is exactly why I'm trying to figure out the whole "swap" (engine mounts, crossmember, tunnel mod, headers, exhaust etc.) even though my post was specifically asking about the tunnel mod. I just recall reading peoples comments about "what worked best" and I can't find it so I started this thread. What crossmember is that? It looks like you've done a lot of modding to fit. I think I need to figure out what exhaust size I need soon as well. thanks for your help and I'm sure it will seem easier once I get at it!


Chassisworks was amazing. Very smooth fantastic piece. Every car in the shop getting a t56 will now use that tunnel. We have already used 2 of them. we will be doing another one soon and I'm sure plenty more. Use any crossmember and then shim the transmission crossmember up to get the correct angle.

Want to know something that everyone here forgot to tell you? No matter what you do 9 times out of 10 everything will have to be modified in some way or the other. There is no 100% this way or that way. Every car is different. STOP and I repeat STOP overthinking it.

Spend the $100, get the tunnel, install the tunnel.

Crossmember isn't isn't with angle. Thats easy to fix. The issue is where your exhaust will come in contact with the crossmember based on the headers you are using and how close you want the exhaust to the floor.

Notice the clearance.
http://i30.photobucket.com/albums/c302/icemanrld19/12009787_10100678567437696_2645136611571591978_n.j pg (http://s30.photobucket.com/user/icemanrld19/media/12009787_10100678567437696_2645136611571591978_n.j pg.html)


crossmember surgeryhttp://i30.photobucket.com/albums/c302/icemanrld19/11846722_10100654819538676_6728932739520720605_n.j pg (http://s30.photobucket.com/user/icemanrld19/media/11846722_10100654819538676_6728932739520720605_n.j pg.html)
http://i30.photobucket.com/albums/c302/icemanrld19/11826069_10100653525995946_404240692632503258_n.jp g (http://s30.photobucket.com/user/icemanrld19/media/11826069_10100653525995946_404240692632503258_n.jp g.html)

the car. the shop also has a lsa 69, lsx376 magnuson, 572 69, and so on and so forth
http://i30.photobucket.com/albums/c302/icemanrld19/11231324_10100678567297976_387481630234051235_n.jp g (http://s30.photobucket.com/user/icemanrld19/media/11231324_10100678567297976_387481630234051235_n.jp g.html)

[Vega$69]

Geez you're overthinking this :bigun2:

[ADiCarlo]

Chassisworks was amazing. Very smooth fantastic piece. Every car in the shop getting a t56 will now use that tunnel. We have already used 2 of them. we will be doing another one soon and I'm sure plenty more. Use any crossmember and then shim the transmission crossmember up to get the correct angle.

Want to know something that everyone here forgot to tell you? No matter what you do 9 times out of 10 everything will have to be modified in some way or the other. There is no 100% this way or that way. Every car is different. STOP and I repeat STOP overthinking it.

Spend the $100, get the tunnel, install the tunnel.

Crossmember isn't isn't with angle. Thats easy to fix. The issue is where your exhaust will come in contact with the crossmember based on the headers you are using and how close you want the exhaust to the floor.

Notice the clearance.
http://i30.photobucket.com/albums/c302/icemanrld19/12009787_10100678567437696_2645136611571591978_n.j pg (http://s30.photobucket.com/user/icemanrld19/media/12009787_10100678567437696_2645136611571591978_n.j pg.html)


crossmember surgeryhttp://i30.photobucket.com/albums/c302/icemanrld19/11846722_10100654819538676_6728932739520720605_n.j pg (http://s30.photobucket.com/user/icemanrld19/media/11846722_10100654819538676_6728932739520720605_n.j pg.html)
http://i30.photobucket.com/albums/c302/icemanrld19/11826069_10100653525995946_404240692632503258_n.jp g (http://s30.photobucket.com/user/icemanrld19/media/11826069_10100653525995946_404240692632503258_n.jp g.html)

the car. the shop also has a lsa 69, lsx376 magnuson, 572 69, and so on and so forth
http://i30.photobucket.com/albums/c302/icemanrld19/11231324_10100678567297976_387481630234051235_n.jp g (http://s30.photobucket.com/user/icemanrld19/media/11231324_10100678567297976_387481630234051235_n.jp g.html)


What size are those tires! Looks good.


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[jlwdvm]

Do you have a T56 Magnum, or a regular T56? I'm interested in looking at the Hooker system as well, but haven't been able to confirm if I can get the proper clearance and angle with their setup. If I remember right, the headers would also need to be modified to make room at the steering box? Not a deal breaker, but want to make sure I look at all my options.

thanks
http://www.pro-touring.com/threads/102040-1969-Firebird-TA-clone-track-car-build/page4
I have a Magnum behind my Texas Speed LS3. I also used Hooker 1 7/8" headers. They don't have to be modified to clear my Lee 600 steering box, but the box has to be out to get the drivers header installed (at least I couldn't figure out how to wiggle it in there with the box on the sub). A header tube will have to be dimpled on each side to clear the Tru Turn tie rod ends if you go that route, nothing major though.

[alongfortheride]

Used a Speedtech tunnel and it works great.

[SIKSEVN]

Was just about to post a thread about my magnum t56 in my 67 firebird and this just answered all my questions 👍🏼

[RPitts]

I just ordered a tunnel from Billy @ B&B classics I will give an update when it shows up.

Rob

[RPitts]

Randy if you don't mind what headers are on that car? That is a DSE frame right? Looking for options besides DSE's little pricey.

[randy]

stainless works.

[RPitts]

Thanks..