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I have an 63 ex drag car that I am restoring. The car was last raced in 2016 and the engine was installled using front and rear motor plates. The frame mount towers had been cut out. I want to install the towers again so I can use stock motor mounts. The frame bracket for the clutch Z bar had also been removed since the car was raced with an automatic transmission. I'm looking for recommendations to get the small block engine mounted in the proper location. I will have to weld new frame tower mounts and the clutch bracket on the frame and I want to make certain they are in the correct location.
I have one old drawing of just the frame, with all kinds of measurements. I will get that out to see if it has those dimensions, as it is in a general notebook that I dont have stored away.
Rex,
If the transmission crossmember has not been removed or modified, I would mock up an engine and transmission assembly and position it in place using the transmission mount to work from. I have a 65 frame sitting in the shop that I could take some dimensions from, just give me a call, you have my number.
Jim
Rex,
If the transmission crossmember has not been removed or modified, I would mock up an engine and transmission assembly and position it in place using the transmission mount to work from. I have a 65 frame sitting in the shop that I could take some dimensions from, just give me a call, you have my number.
Jim
Thanks Jim, but the crossmember has been highly modified.
If you are trying to precisely replicate the original engine mounts, I can't help. But if not, I agree with JRM5657's suggestion. When I built my Cheetah tribute I mocked up the entire drivetrain to get clearances and driveshaft angles right and then tack welded the motor mounts where they needed to be. When everything was out of the way I finished welding them in.
Do I remember correctly that the engine in a C2 is actually offset slightly from the center line?
Yep, notice in the diagram posted above that the driver side engine frame mount is longer than the passenger side. When those frame mounts are purchased welding them into the correct position will provide the proper engine offset.
found this on the web. Looks like the motor mount brackets are 23 3/4” at the front edge to the front frame horn.
hope this helps.
Chris
That's a C3 frame. The Tail is different and I think the front horns are different. I expect the C2 dimensions are at or very near these specs, but I would find a 63 frame drawing to be absolutely sure. I think there is a 63 drawing out in the internet also somewhere.
I've also wondered why Corvette engines are offset. I learned a new word from JohnZ's write-up: Brinnell
It is true that you don't want a perfectly straight driveline due to what was mentioned.
It is also true that all the mid/late (and later) '60's Chevrolet car lines excluding Corvair and possibly Impala, had the engine, transmission offset to the right and that was to give more room for the pedals in the driver's foot well.
Unless I'm missing something on that frame drawing, I don't see much advantage in using it to locate the engine. Don't see dimensions to key reference points, especially height.
I believe if I was doing the work, I'd eyeball it like this. Determine the height of the crank center line above the front crossmember, the height of the transmission in the linkage opening and the location of the shifter handle relative to the opening. Easily measured off other Corvettes.
Mock up the engine/transmission, shifter to match those measurements. Weld in a new, production transmission crossmember to hold those dimensions and then move to the front. Attaching the new motor mounts brackets to the engine, the free end should fall in place on the frame in the right relative location. That is, as long as something isn't reefed out of shape.
Check the frame to make sure it is square. Draw a line at those dimensions and mock an engine up with mounts attached, and set those bracket down on the line. So the tilt? I would probably put the tranny crossmember in first. That should be level to the frame. I would put a bolt-in in. I think the offset is in the brackets (length and configuration of each), but never studied that on my cars. Do you have the brackets yet on hand?
Last edited by TCracingCA; Feb 26, 2021 at 02:09 AM.