Wanted to post some pictures and descriptions of my automatic to manual transmission conversion in my 1971 Chevelle, in case it was useful. This process should be roughly the same for all 68-72 GM A-bodies, but YMMV.
I'm going to gloss over the TH350 removal, as it is pretty straightforward, and focus more on the issues relating to stuffing the T56 Magnum into the car.
So the plan is to cut the tunnel out, insert larger patch with opening for shifter, design custom center console to fit over new transmission tunnel, then reinstall.
Here's the victim: 1971 Chevelle with a Dart 427ci SBC, 12 bolt rear, truetrac diff with 4.11's, aftermarket front and rear suspension from SC&C.
It's pretty heavy - shipping manifest says the package was 39 lbs, so probably a few pounds less than that. It's model RCAE btw. They don't have it specifically listed on their website for a 71 Chevelle, so I had to call and make sure this was the correct one.
Thanks, everyone. I will rethink my plan regarding the drain plug. I had initially thought I could notch it, but that QuickTime bellhousing is super thick! Will see what I can come up with, because I'd love to not have to mess with the oil pan at all.
Was able to go through the bellhousing alignment procedure using the alignment plate from holleys website. Everything worked great and was within spec, ready to move to the next step of measuring clearance for the hydraulic T/O bearing.
Yeah, I was relieved for sure! I did actually recheck parallel since 0.003 seemed a bit much, and it ended up being 0 run-out (dial faced had just moved...).
I'm using a bushing too, and so far it's been really difficult to get input shaft to slide in. Going to keep working on it, and glad to hear I'm not the only one experiencing that really tight fit. Will just keep working it on, and will definitely not use bolts to pull the trans on!!
Was able to install the clutch and bellhousing using the billet alignment tool. Seems to have worked well, but we'll know for sure once I try to slide the trans in.
Also measured T/O bearing clearance. Had to put on 8 0.045" shims to get the air gap to 0.159". Seems excessive, so going to recheck this measurement to be 100% sure.
Having issues getting the trans in the last 1/2" or so. I think the bearing clearance is pretty tight at the input shaft, which is why it's not sliding on easily.
yeah, I checked - it slid on no problem. Also checked that it fit the billet alignment tool as well, and felt exactly the same.
I'm thinking the inner diameter of the bushing may have shrunk a bit after the installation. I also measured the alignment tool to be 0.003" smaller diameter than the actual input shaft on the transmission. Thinking those 3 thousandths are making it pretty tight to fit the input shaft in...
Same exact problem I had. I got some like 2000 grit and polished it down a bit using a socket so it wouldn't egg shape.
Fixed my issue.
It is annoying but it's working great so far. No oddities or anything in my case.
If you have a wheel cylinder brake hone, run it in and out of the bronze bushing a few times to give you the clearance back , sometimes its just a small bump or nick - FWIW.
Been a while since I updated - traveling for work and then family time at Thanksgiving!
Anyways, I realized the issue with the previous attempt at the trans install was the the clutch discs just came misaligned somehow (tried install tool and couldn't get it to go in). So took everything apart, reinstalled the clutch, all gtg this time around.
One thing that did help was for me to put a digital angle finder on the face of the trans, and the back of the bellhousing to get them as close as possible before trying to get the trans in. This helped a TON.
The CAD drawing is definitely just conceptual at this point, so I could have something to aim for. I was just using free Google Sketchup for the time being. I had originally planned on making at least the sides out of MDF, but I will be getting a sheet metal brake here soon, so it might be worth thinking about going down that path instead...
I definitely like the idea of being able to do it out of one full sheet of sheet metal, kind of like the templates for a cardboard box all unfolded. There will definitely be some complex geometry, so I will have to take some time to draw out the flat template and the order of operations prior to starting the bending!
I probably will lean a bit on the console, so I plan to put 2 or 3 different mounts to the tunnel along the length of the console - I really don't want it to flex at all and feel cheap!
I had planned on using some kind of high density EVA craft foam for underneath the microsuede and the leather. And as for wrapping everything, I was considering trying my hand at sewing, and maybe even some french seams? Never done anything like that before, but I've also not installed a trans before either!
So I was able to get the master mounted. Ended up using the top left bolt holes for the firewall plate as one of the mounting holes. Ended up with the rod nearly perfectly in line with the throw.
Holidays and family took priority of course, so just starting to get back into the swap.
Was able to center the engine and trans to the body centerline. Just need to loosen the engine mounts and used a ratchet strap to pull the trans tail towards the passenger. It literally popped into position, so it seemed like it wanted to live there.
Bonus was after everything was centered, and I squared up the crossmember for drilling new frame mounting holes, I checked the yoke fitment, and I now have full clearance for 360° rotation.
Albeit, there's only about 3/16" clearance to the body at the top, but I have yet to change out the body mounts to the poly ones, so hoping that will help!
I think you will want more than 3/16", but the Poly mounts should make a pretty big diff. It did on mine. Under normal driving, I am sure it will be fine. But things flex quite a lot over abrupt bumps.
Was able to get all mounts on the driver's side done without too much hassle - no broken bolts or nuts at least. Being a CA car, it's pretty rust free everywhere.
Just for sh**s and giggles, measured the floor to fender lip on the front driver's vs passenger side to see the difference. I haven't torqued the mounts down yet, but the driver's side measured 25.25", and the passenger was at 24.5". Will be interesting to see the final height once both sides are done and properly torqued.
Finished install of the poly body mounts. Wasn't too bad, but definitely learned some tricks along the way. Make sure to remove all bolts for all mounts along one side of the car, then jack up the body in 2 spots at the same time. This should allow you to replace all the mounts on one side at the same time.
Also, I fought for waaaay longer than I car to admit with removing the bolts of the second body mount from the front (just in front of doors). GM decided to use an uncaged square nut inside the frame, which was super awesome to deal with. At least the new body mount bolts come with a 12 point but instead of the old square nut...
So I have plenty of clearance at the trans now, and it is finally time to disassemble everything for the last time, clean the undercarriage, weld in the new tunnel, and install for the last time.
Hi All - long time since I provided an update. Lot's going on, so haven't been able to post. Some upgrades came into the shop, and I wanted to wait on this new equipment to continue with the trans install. Got a bead roller, so I was able to put some beads around the radius of the new tunnel patch - looks like the factory piece I cut out, and added a TON of rigidity to the panel. Highly recommend if you can make it happen.
Decided to use 3M panel bond for installing the tunnel patch. Never used it before, but it worked beautifully. I just used long self-tapping screws to hold everything in place while the panel band cured, then removed the screws, and covered the holes with some more panel bond (just smoothed over with my fingers, worked great!).
Not sure why my pictures are rotating themselves again...
Anyways, with the tunnel installed, I wanted to clean up the underside of the car, and WOW was that a super messy job. Couldn't believe how much junk had accumulated under there in the last 50 years - and this has been a CA car it's whole life!
Anyways, just used a scraper to get large chunks off, then a grinder with a flap disc to bring down to bare metal. Followed this all up with a thorough clean with denatured alcohol, and covered with POR-15 gloss coat. It looks AMAZING under there now. I love the self-leveling properties of this stuff, and the finish is so smooth to the touch.
Once everything was painted, I wanted to install a heat shield for the trans and the headers. Ended up going with DEI aluminum self-adhesive heat shielding, and it looks fantastic. Looks just like the stuff you'd find on new cars. Just made a template with paper from the inside of the car over the trans tunnel, and extended it far enough to cover where the headers were located.
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