Auto to Manual trans. swap

[ChrisH]

A good friend of mine has a '81 Vette with an automatic and is wanting to change over to a 4-speed manual. I told him I would do some research on parts and modifications needed. I'm sure some people here have performed this swap and I was hoping I could get a total parts list, an idea of the mods. to the car to make this happen. He has owned this car since '95 and has been talking about how he wished it were a 4-speed for the last four years at least. Any help would greatly appreciated. Thanks!

Chris

 

[GotMy81@16]

This wont help you Chris, but I too own an '81 and would like to swap the automatic for a manual. If anyone knows anything make a reply.

 

[90 KOTH]

I'm doing auto to manual 79

I'm just getting starting on swapping a Keisler-Tremec 5 speed into my 79 automatic and have started accumulating the parts needed. I recommend starting out with a factory assembly manual which shows diagrams of all the parts needed from the pedals through the linkage to the flywheel, clutch and bellhousing. Many of the parts are available through one one of the major Corvette parts suppliers or you can go the used route via ebay or a salvage dealer. Most everything is fairly easily available but the cost adds up fast. One of the issues with the later C3s is there is no mount for the Z linkage on the frame. I've heard that there was a bolt on piece for the 81's but I'm just going to weld on a bracket. I also have to pull my engine and drill and tap the block (it's a 406) for the pivot stud on the other end of the Z linkage.

Anyway, it's a lot of work but I'm tired of my auto and the project should keep me busy for a while. Hope that gets you started.

Regards, Phil

79 Red/Oyster Coupe, 90 Red/Red ZR-1

 

[JohnZ]

No need to drill and tap the block - Scoggins-Dickey sells a bolt-on adapter bracket for late blocks without the hole for the clutch cross shaft stud for about $60.00. Most auto-to-manual conversions end up costing $1500-$2500 by the time you add up all the little stuff, not counting labor.

 

[Bob Chadwick]

I'm not expert on this by any stretch but I followed some of the posts 69MyWay made and as I recall, the conversion was easier if you went with a hydraulic clutch. Might want to do a search as this question comes up several times a year.

 

[Dave L.]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=34208&item=2458601477
Here's a good start!

 

[90 KOTH]

Z-bar Pivot ball bracket

John, Do you know of anyone that's used the pivot ball bracket on the 400 small block? My block has the boss for the hole on the block but it is not drilled. I found the bracket you mentioned at SDPC and called to ask if it would work but the best could say was maybe. They said it was actually designed for the new big blocks that appaerntly don't even have the boss cast in. If no one knows, then I'll just order one and give it a try and report back. It would sure make the installation a bit easier.

Regards,
Phil

 

[JohnZ]

I haven't used one, but it should work, based on what I've heard from others; the block-to-bellhousing joint is in exactly the same location fore-aft for both small and big-blocks, and both engines used the same bracket welded to the frame.

 

[tom81]

Dave,

Thanks for the heads up, been looking for that item off an on for about a year and a half now.
Sorry Chris.

Tom.

 

[Dave L.]

I like to visit Ebay about once a week just to keep an eye out for interesting corvette stuff.

 

[brusso]

One thing comes to mind. Whenever I've had to order a replacement engine, I've had to specify automatic/manual trans. This was because, for the manual trans, the crankshaft had a drilled machined hole on the end. This was so that you could have a place to insert the clutch disc pilot tool to align the friction disc, before torquing the clutch cover to the flywheel. The automatic optioned engine does not have this pilot hole. Not an incredibly big deal but if you have trouble getting the trany spline to line up to the friction disc, now you know why.

 

[90 KOTH]

I believe that hole in the end of the crank is also where the pilot bearing and tip of the trans input shaft fit so, without the hole, the manual tranny won't fit. Good to know in case I ever buy a newer engine or crank.

Phil

 

[tom81]

I happen to have my motor out and checked to see if the crank was drilled out for a pilot bearing and it is. Which I’m now thinking maybe a little odd because the motor is original (at least the block 1BS400113 from St. Louis) to the car, which is an automatic. Perhaps it’s been rebuilt and had the crank replaced. I will have to do some investigation on this.

Would crank casting ID be the same? probably so.

 

[JohnZ]

All factory cranks after 1958 or so are drilled for a pilot bushing; the only difference from then on between a manual and Powerglide engine assembly as-shipped from the engine plant was that one had a flexplate bolted on, and the other had a flywheel, clutch, and bellhousing - the cranks were all the same, except for Turboglides.

 

[tom81]

John,

Thanks for the info. One less thing to worry about.