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Discussion Starter #1 (Edited)
The donor body for this project started life as a red, 2008 GXP convertible. The motor is an Ls7 crate (Corvette), differential is a Gertrag 3.73 and the transmission gear ratios will be: 1st 2.66, 2nd 1.78, 3rd 1.3, 4th 1.00, 5th .74 and 6th .50. Transmission selection is in process but leaning to the Ford Tremec Magnum XL.

Motor mounts were obtained from Wade Linger along with a welding jig he kindly provided. The Ford specific transmission will get its input shaft exchanged for a GM style, and along with an Ls aluminum bell housing and GM hydraulic clutch unit, fitment to the back of the Ls motor should be possible.

A distance of 33 inches is needed to reach the OEM, 5-speed shift column location (center), from the bell housing mating surface on back of the motor. OEM GTO, Tremec F-body with extension and the OEM 6060 with remote shifter (modified) will all work. I am hoping the XL will be close enough to be fitted with a crooked shift column, precluding cutting the tunnel, using articulated extenders or modifying the remote shifter length.

The pictures show the tacked motor mounts after removing the OEM ones that spanned the cross members.



Front covers will be fitted to the mounts. They are not in place because the front of the mounts need to be exposed in order to reach the inside during final welding.
 

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Looks like fun. Will be following along.
 

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The TR6060 is probably the best trans of those choices, but may not be the best fitting.

Looking forward to more progress.
 

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Discussion Starter #5
Initial pricewise, the 6060 at $2680, with bell housing and clutch hydraulics, no doubt is the cheapest. After much consideration, I am not sure I can fit the XL in there. May be just a tad too long. One thing is for certain, fitting the 6060, at least as far as positioning the shift column is concerned, will be possible. On the XL it will fit where it falls. On the F-body trans, it will be closer to where it needs to be, but a cut of the tunnel will be required.
 

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Discussion Starter #6 (Edited)
Selected ratios and ideas. Tremec has produced variety of ratios for OEM applications (TR6060) but in the aftermarket (T56 Magnum) for GM appliactions, only two are available.

1st 2nd 3rd 4th 5th 6th rev
3.01 2.07 1.43 1.00 0.84 0.57 3.28 SSR Truck
2.97 1.78 1.30 1.00 0.80 0.63 2.90 Camaro
2.66 1.82 1.30 1.00 0.77 0.50 3.98 Corvette
2.26 1.58 1.19 1.00 0.77 0.63 ? Viper

Using experience and ratio information from three of my cars (1986 Mustang 5.0, 1994 Nissan 300zxTT and 2007 Honda Civc Si), I selected the Corvette ratio above. Let us consider the Civic. Weighs about the same s the Solstice, 3000 lbs, and has a 2.0L NA engine the spins to 8500 rpm (with Hondata flash). 1st is circa 3.3 and diff ratio is over 4. 80 mph RPM is 3500+. The 200HP engine is very weak at the low end with anemic torque, just over 100 ft. lbs. This low gearing combination works well with a weak, high revving engine that can still get the car moving fast by spinning up the motor.

The Nissan has 400 HP (with some mods, boost, intake and exhaust) but engine is little at 3.0L and a max RPM of 7500 (with reprogrammed ECU chip). Weight is a porky 3400 lbs. 1st is 3.3x and diff is 3.69. 5th is .6x with cruising rpm at 80 mph under 3000 rpm, but close. In this case there is a heavy car (relatively speaking, about the same as a corvette) and a smallish motor that revs respectably. Having a turbo has benefits running revved up, as it keeps the car responsive, at the expense of wear and fuel consumption.

Come the Solstice. OEM weight with the 4 cyl was circa 3000 lbs. Let us estimate 3250 with the Ls7 and Tremec T56 Magnum. The engine is modestly revvy, 7100 (not bad for a pushrod V8) and produces over 400 HP and 400 lbs of torque. With this combo there is little need for the transmission to help the engine. The combination of gear ratios (2.66 ... .5), diff ratio (3.73) and car weight, resembles the factory configuration for pre 2015, Z06 Corvette.

The Ls7 has titanuim rods and a 30% lower weight reciprocating assembly. The reduced mass of its internals should allow it to change rpm quicker than a comparable motor with heavier internals. I also replaced the OEM flywheel with a Fidanza aluminum unit, seeking torque reduction off the line to reduce wheel spin. These are all fact based theoretical estimates, but non-the-less just good guesses. We shall see how this all works when put together.
 

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Discussion Starter #8 (Edited)
The motor area is progressing nicely. The motor mounts have been finish welded and the "noses" of the OEM mounts added to the front for a bit more strength and better looks. The tunnel brace flange had been cut, about 6 inches on each side but the bell housing was still too close. We added another 1/4 inch on each side and ground of a pair of casting protrusions that may have something to do with the casting process or mold fitment of the bell housing. Since the spot welds were on the flange that was removed for clearance, the edge was welded to fuse the two pieces of metal that comprise the tunnel brace. The black shape seen on the rear cross member, is the spot where the Ls7 sump drain is located. There is about 3/8 of an inch of clearance between the oil pan and the rear cross member. Unfortunately the the drain plug has a collector valley that protrudes about 1/2 below the pan. Until I cut a hole for this to fit the engine just rests on the rear cross member and will not accept the transmission input shaft.







 

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Christ, I wish I had the talent to pull this off...
 

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Discussion Starter #10
Sly.., you buy what you can ready made and hire a welder. Painting was made with rattle cans. Not too big a deal. The financing is perhaps the most challenging, knowing full well, that the market value of your creation will be less than 1/2 of your expenditures.
 

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Discussion Starter #12 (Edited)
Plastic engine with exhaust manifolds installed. Motor bolted to the mounts and bell housing. The manifolds are from Performance Motorwerks. Fit against the car is acceptable, but only one O2 sensor bung was provided on the right side manifold and the motor flanges need to be modified to clear the coolant temperature sensor in the front right side head, and the plug in the rear of the left side head (same head is used for both sides). I should have not requested jet hot coating. After mods headers will need re-coating. Engine swaps in most cars are not this tight, requiring living with very close clearance tolerances. I am trying to stay to no less than 3/8 of an inch. Notice right manifold side is closer to frame. Left side was made tighter to clear steering shaft/u-joint.

Engine on lift sitting on original crate. The hydraulics on my Chinese lift do not hold pressure for extended periods of time. If motor were to be left hanging, it would reach the floor overnight.

I am having the transmission mount modified. The way it was made allowed no front-to-rear adjustment of the transmission location. The motor mounts have slots about 1 inch long, but even all the way to back I still could not reach the bell housing. I could see the isolators deflect when I forced the union of the motor/trans. This is a moot pint though, because in order for the headers to fit the motor has to be at the extreme front of the slots. Even at that spot the isolator pads overhang the mounts just a hair.









 

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Discussion Starter #14
Barely fits. Worried natural movement afforded by rubber isolators may result in contact somewhere, especially as they break in or wear. If this happens I may have to suffer the indignity of urethane vibration.
 

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Discussion Starter #18
On a test fit, the belly of my engine is only 3/8 of an inch above the rear cross member. Are you using the stock motor mounts that are taller? My son has a car with reduced suspension travel (lowered) and urethane motor mounts. I have to wear a kidney belt when I ride with him.
 

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I'm using the C6 brackets, shorter C6 engine mounts, and stock mounting pads. The oil pan is about 1/4" from the rear crossmember at the closest point.

On a test fit, the belly of my engine is only 3/8 of an inch above the rear cross member. Are you using the stock motor mounts that are taller? My son has a car with reduced suspension travel (lowered) and urethane motor mounts. I have to wear a kidney belt when I ride with him.
 

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What will you be using to control the engine? OEM LS ECU?
 
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