My pleasure Brad. I thought it would be a good guide line for someone who may be contemplating some sort of manual trans overdrive along my lines of performance thinking. The swap could have been less costly if I didn't use the QuickTime bell, dual disc clutch or maybe even this type of a hydraulic clutch system, but I also saved on no completely new driveshaft and x member. Take the numbers cafeteria style, to suit the way you want (or need) to go. I did not include the cost of the suspension relocation brackets as they weren't really associated with the swap and I already had adjustable upper control arms and other suspension pieces. Don't be intimidated by the trans tunnel work for the 6 speed. You'd have to do tunnel work, regardless for a 5 speed Tremec and if you wish to go mechanical clutch linkage there is also a 6 speed bellhousing available for this. Now off to find some stickier tires after filling up with that 94 octane... Tom
Did some full throttle shifting at 6,600 rpm (my redline) from 2-3 and 3-4 and it worked flawlessly. Credit that to the additional dial indicating and correcting the input shaft runout of the trans to the crank. Tom
Sick Speed update: With the summer season gone I managed to put on over 1,100 miles on the install without any failures. Some of those miles ended up pretty hard so I wanted to do a check while putting up the car for winter. First on the list was a changeout of the Dexron III fluid that had been in since the start. The old oil turned out to be really clean and without any metal, however..... there was a bit of dampness on the rear seal. A simple $10 rear seal from NAPA, #12049, solved that problem and came with a metal flange as opposed to the factory one without. All current T56 Magnums sold have a modified extension to prevent the problem. The UMI relocation brackets are working with respect to absolutely no wheel hop, but traction is still limited with the BFG G Force tires. I never did get to try sticky tires as my slick rims don't clear the the big rear vette brakes. I've retuned the Dominator and used different air bleeds for a better idle circuit to main jet transition so that lazy cruising in 5th & 6th gears is better at 2100 rpm with the radical cam. Tom
Some un posted pics from the build: Tight clearance between the hydraulic clutch shaft and brake switch Before Pic of auto shifter and factory console Tight clearance around throttle side floor to left ear of T56 Magnum Tom
Hey Tom, The car looks great. Happy to hear everything is going well with the swap. What’s the plan for the car going forward? Do you plan to auto cross it at all in 2021?
Hey Tom, I thought you might be interested in what I did about the clearance issue between the hydraulic clutch rod and brake switch. I heated and bent a piece of steel rod to creat an offset and I cut and welded, the provided threaded coupling nut, to the ends, in order to use the heim joints, to make the original connections. Clutch works great with no worry of interference
Don't know if I 'll get into any serious auto crossing but will give it a try. When covid is cleared up and Bowling Green is back I want to bring it and a turbo car to the nationals again and maybe attend a pro touring event in the future sometime. For the immediate future, There may be some new rims and tires, some more Chassis reinforcement, perhaps Corbeau seats and trying out some custom cam grinds that I have had lying around. It may be interesting to try a slightly different powerband with this transmission's gear spread. I think exhaust is another area I want work on. Perhaps cut off the collector flanges and weld reducers direct so I can get more ground clearance. Tom
More unposted pics from the build: My Tremec T56 Magnum had a an optional adjustable offset shifter stub/top plate included, so I used it to optimize the stick and ball for my driving preference. If you look at NASCAR roundy round cars the shifter is generally in close proximity to the steering wheel allowing fast maneuvering between the two. Picture shows shifter in the middle position location with a stub offset of 2" to the rear and located in the center of the "Tin Man" prefab tunnel. Had the car to a roundy round frame shop last summer to check the measurements after my rear suspension adjustments. Rear turned out to be on the money to the front. (within 1/32" or 0.031") When installing the new carpet I used new Stainless Steel sill plates over the aluminum ones that most use. These guys are much tougher against seat belt buckle damage.
Was talking to a car collector & show promotor recently, who was of the opinion that big horsepower cars with 6 speed Tremec Magnum's are bringing in higher dollars these days.
The T56 Quicktime bellhousing & block plate, for BOP, had both pass and driver side openings for starters without provision to block the unused opening, so I fabbed a cover plate on the bandsaw to keep road debris & unwanted oil out. Last summer I had a steering box seal go on me and some of the power steering oil sprayed into this area.
Attached pic of Prothane trans mount and shimming to get the driveshaft geometry where I wanted it after modifying G force X member to fit and provide exhaust clearance.
Two years down the road update. The swap is working very well and is still puts a smile on my face every time I'm out. I did retune the rear lower control arm relocation brackets to a 2" drop (upper hole in the UMI bracket) to gain a more balanced braking. The lower positions provide a harder hit on acceleration but adversely affect braking by unloading the suspension during harder braking. Underside view from the rear showing the modded G force x member. Yes the mufflers are different from the initial install. I was getting tired of the Blowmaster rasp that occurs from 4000 up. These Vibrant 3" jobs are 304 SS straight throughs with two different media for noise attenuation. Steel swirls and Rock Wool. Great sound without rasp. 6 Speed Shifter ball changed to one with a Hurst inscripted logo, only because my son bought it for my birthday. Yea its better quality, but won't make me shift any better. This is what I now will be running for trans oil this season.
Changed the speedometer face to represent a stick shift car without the Park, R, D, L2, L1 markings At the same time, modified the driver seat for 2 additional inches of driving leg room for my 6'3" height. Jr. who occasionally drives the car is close to 6'6"so this is especially a welcome mod for him. Did this no cost trick, without seat extender brackets, by redrilling the factory bucket seat to mounting rail position holes per a Chevelle site thread I read. Also decided to use an Aeromotive Fuel Pump Speed Controller to cut back fuel during low rpm use, especially in overdrive gears. Helps with fuel heat and pump wear on longer trips. I like that he controller also features a manual override for full speed operation.
I saw this thread back in March, did some research and switched over to the Vibrant 1106 mufflers in April on my 71 GS. I had Walker 17748's on the car, I was surprised that the Vibrant's were quieter at cruise with less drone. I also gained a couple tenths and maybe 1-2 mph, although any number of conditions could have had something to do with that too. Interestingly, I prefer the sound of the Walkers when standing near the car, but we dont buy mufflers for sound....