Tremec 5 speed, trans tunnel cover and swap to front or mid shifter location?

[Chuck78]

My old crashbox SM318 sounds to have some gear damage in first now, so it's time to swap in one of the two Tremec 3550's (predecessor to the TKO) that I have for the 62 GMC Panel and the 71 Camaro... My first question is, do I need to switch to the taller hump trans tunnel cover? It doesn't seem that I do, but just wondered.

Secondly, going from a three on the tree, I really like the ability to haul long pieces of lumber in my panel truck with the barn doors shut, all the way to the firewall. Now I was wondering if anyone had ever ran the front shift location in a Tremec 3550 or TKO in one of our trucks? I figured maybe I might have to get a custom shifter lever in place of the Tremec kit's, something with more of a kickback, but wondered where this will really put it. I kinda wanted a fairly tall shifter anyway, reminiscent of the Rat Fink hot rod look, but not quite so obnoxious. The mid shift location says it's for most truck retrofits. I know that the rear location doesn't work for bench seats. The mid location is probably 4" to 7" more forward (16.75 or 19.5" depending on mounting forwards or backwards) vs the 12.75" mid shift location, and I think I remember the front location being about 7" from the front of the transmission/bellhousing mounting surface. Wondered what this would do for me, and if it would just be way too far forward.

Also, will a really long shifter make the shifting really funky? Obviously, the taller the shifter, the more travel my arm will need to do to get the same shift vs a short shifter. It's not a hot rod so much, though it will look like a cool rat rod, but I still use it as a truck to haul and tow, and it's most likely going to keep the monster GMC 305 V6 since it's got so much torque and is a very cool and unique engine. Although I have two spare 400 small block chevies in the garage if the big block 305 V6 ever goes caput. Although a GMC 351E (has all the Magnum parts) or 401M (Magnum) V6 would be even more cool to throw in there! Parts are hard to get quickly for any of these, and the SBC, even the 400, is such a universal thing, but so common and overdone... But I can find parts easily when on a road trip...

Also, should I just be looking for an auto trans crossmember to use when swapping in this Tremec? The 3 speed manual doesn't use a crossmember, it just hangs from the bellhousing, where the bellhousing has rubber mounts to the rear of the engine crossmember. The SM318 is so small that it doesn't need any rear mount apparently.

[62 mark]

This transmission has the non removable bellhousing if i am not mistaken. If your 62 is like mine, with the motor mount on the front of the engine,you may have a problem ,since you will be eliminating your old bellhousing(with it's mounts) I can't answer about where the shifter will be ,but i would guess about 6 or 7 inches back from the stock 4 speed location. you should be o. k . with the low floor hump . You could check with some of the aftermarket shifter companies like b&m ,they may have a shorter throw shifter for that trans. i was lucky to find a world class t-5 for my 62, it will bolt right on to my stock bellhousing.Hope this helps.......Mark

[Chuck78]

The Mustang Cobra/GT whatever Tremec 3650 5 speed has the integrated bellhousing, as does the New Venture NV3500 5 speed on newer GM 1/2 ton trucks. These WILL NOT WORK whatsoever with mine, as the GMC V6 takes a specific bellhousing for the engine side bolt pattern, and also due to the extreme weight of the monster truck engine blocks (they are true truck engines, built like tanks and last 300,000+ miles), you need the extra support of the "rear engine mounts" as they were called, but really they are mounts on both sides of the bellhousing at the back of the engine crossmember.

Another thing is that the GMC engine takes a GMC flywheel, which has the pilot bearing in the flywheel like some of the old Pontiacs, so it takes a specific clutch (probably the same as the old late 50's Pontiacs) which is basically the same as most 11" musclecar clutches except the center hub with the splines protrudes out the opposite side of the clutch disc! A remanufacturer like Hite Parts Exchange here in Columbus, OH can rebuild the original 11 spline clutch and factory pressure plate like I had done, and can also take a standard GM Musclecar type 26 spline 11" clutch and dismantle it and reassemble it with the hub reversed, so it will not interfere with the pilot bearing - as the stock GMC setup is.

I was just mainly curious as to what people are doing for crossmembers aside from dropping huge amounts of cash on pre-packaged kits with custom crossmembers already made. Wondering how many people just made their own entirely, or if most people are taking an auto trans crossmember and making it work, having to modify it, etc. I have a 62 GMC with the X-frame setup, so not sure if the 63-72 crossmember will work at all, and the 60-62 is probably a much harder score to come by.

I'd love to fab my own up and have more pride in it, but that means more time spent figuring pinion shaft angle on the differential, and adjusting the drop height on the crossmember to get the transmission output shaft angle parallel to have proper driveline angle. More work, but if a crossmember costs $200, then I will be making my own!!!!

I see the mid shift kits from Pro 5.0 cost about $329 for everything but the shifter lever/handle. Not seeing much on the front shifters, but I would imagine the cost is similar. The location and any dash interference is what I am concerned about, but I'd like to have it as far forward as possible with a big kick back in the shifter at seat height so it is still within reach!

For the Rat Fink look, maybe a mid shift location with a real tall shifter/knob would be the best!

[Chuck78]

I will be needing this speedo adapter to go to the GM style cable, as I believe (correct me if I'm wrong), they come with the Ford style, after all, they are designed after the Ford Toploader transmission with an OD added. C6 Ford output shafts also...

http://www.5speedtransmissions.com/gmspeedoadapter.html

Also says they use the TH350/TH400 trans mounts. Maybe an auto crossmember will work? might have to move front or rear, but that's easy enough.

[Chuck78]

Any tips on crossmembers, other than total custom fab or buying a $200 aftermarket piece designed for this swap????? Has no one ever had any experience with the front shift location?

http://www.mperacing.com/drivetrain.html

That F*$d Rustang place has Pro5.0 Mid shifters for the Tremec 3550 for $329. I think I saw a TKO Mid Shifter kit for $289.99 somewhere.

[CWT]

I used a bolt in CPP one for a TH350/400. You can place it wherever you need to. It was less than $100. I used a T5 in mt truck so I dont see why a TKO or 3550 would be any different to mount the rear to that crossmember.

http://www.classicperform.com/Store/...cks/CP9424.htm