MV5 vs MV7

Welp, I think I may have screwed up by buying a MV7. I had assumed the MV7 and MV5 transmissions were basically interchangeable – why would there be significant differences in the “same” transmission between two cars made by the same company? This assumption turns out to have been a bad one.

It took about 4 weeks to get in touch with V8R – not the best customer service experience I’ve had. They finally told me that the MV7 requires a different frame rails, crossmember, and driveshaft. The MV5 driveshaft they provide uses an aluminum adapter to attach to the transmission (image below from @rdb138 ) and the MV7 driveshaft bolts directly to the transmission:

I wanted to understand what exactly drove the difference so I dove into the service manuals and parts catalogs (MV5, MV7) to try and understand the differences. I may have definitely spent entirely too much time doing this. From what I can make out, it seems like there are a few non-interchangeable parts but the important ones (input, output shafts, most of the shift stuff) are the same or at least interchangeable. The countershaft is different, but that’s to be expected since the gears are fixed to the shaft and the ratios are different. The primary differences are (bottom to top) the RR transmission case, transmission extension, and the output flange:

Basically the third and fourth transmission cases from the bottom and the output flange. Obviously the output flange is an issue since it interfaces with the driveshaft, and the transmission extension (top case) is an issue because the transmission mounts are different:

That leaves the RR transmission case. I’m inclined to say these are not interchangeable – the 1-2 shift shaft isn’t interchangeable, which could mean it’s a different length. If I say, had a MV7 and wanted to swap over the MV5 case, I’d be worried that the bushing the 1-2 shift shaft rides in would be in the wrong spot and the shaft would either bottom our or be unsupported. Hard to tell without having both in my hands, they look pretty similar in pictures but they have different part numbers for a reason.

So, what does this all mean? I THINK if I can get my hands on the MV5 output flange and transmission extension I may be able to make this work with the MV5 kit I’ve got. I’ll have to figure out the reverse sensor wiring and go without a transmission temperature sensor, but those are acceptable compromises.

The hard part is going to be finding the parts – you can buy the transmission extension new (~$150) you can’t buy the output flange from Chevy. A used MV5 is ~$1k, unfortunately. Anyone have a MV5 they want to part out for the sake of science?

The other option would be to just buy a MV5 and use it as-is. But where’s the fun in that when I could make this way more complicated?

Engine Install

Well, last week was quite a week.

I’ve been casually browsing Camaro engines for the past few weeks, every time I searched I felt discouraged by the generally high cost and lack of low-milage engines. Most of the listings were around $2500 for just the engine (~100k miles) plus another $700 for shipping, with no guarantee that the wiring harness or accessories would be intact. Like others found, a lot of the motors were already pulled and stripped of all the accessories, which would further increase the cost.

I then remembered Keisler recommends buying FWD drivetrains and converting them to Camaro-spec. A quick search confirmed that not only were the engines much cheaper (some sub-$1k), but they were plentiful and available locally. I found an Impala engine locally with ~3k miles on it and I jumped on it, I paid ~$1600 out the door. I could have saved some money and bought a higher-milage one but having a basically brand-new motor was too tempting to pass up.

Transmissions were a similar story, most were $600-700 for a MV5 with >50k miles but they were at least available locally. The MV7 has better ratios, but being rare I assumed they would be a lot more expensive \ hard to find. To my surprise there was one locally with 108k miles, once I double checked my search terms I called them and picked it up for $350 out the door.

The drawback to the FWD approach is I now have to buy \ locate a LOT of little parts. I made a spreadsheet to track the parts \ part numbers I’ll need to mount all the accessories, as well as an estimated cost comparing buying a FWD engine vs spending more on shipping a Camaro engine. I actually made this before I bought the FWD drivetrain to see if I would end up getting nickel and dimed to death – turns out it’s about the same cost either way, and you end up with a much lower milage engine \ newer parts going the FWD route. It’s definitely more of a hassle, though – annoyingly all of the accessories \ brackets are unique to Camaro, plus I had to buy about $150 worth of hardware that was missing (another tab in the same spreadsheet).

If anyone else goes the FWD route this site was invaluable for finding part numbers for brackets \ accessories \ hardware, etc. (and another plug for charm.li for the factory service manual). GM was nice enough to list the bolt spec on all the hardware which made finding the same hardware on McMaster easy. Instead of spending $5/bolt from GM, you can get 10 for $10. Although the spreadsheets links to all new parts I may end up buying some of the more expensive ones used from car-part.com.

The V8R subframe also showed up last week, which meant after hacking up a moving dolly and installing the new Camaro oil pan…

I could install the engine and transmission:

I took advice from @rdb138 and @gooflophaze and built the dolly so the subframe’s chassis mounting points were high enough to level the car with the drivetrain installed. Having everything on wheels was super helpful and made hammering the firewall easy – I could just roll the engine forward, hammer, test fit, and repeat. I may have gotten a little enthusiastic with the hammering, I tore the firewall in a few spots. It’ll be easy enough to TIG back together next time the engine comes out though.

Now that the engine is in I can order the wiring harness ($500 new from GM) and finish wiring the car. I’ll need to pull the drivetrain again to install a bunch of stuff (I threw it together just enough to get it in the car) but this will let me move forward with the wiring.