1966 Buick skylark 455 convertible swap to manual transmission

Hi
I have a 1966 Buick skylark 455 convertible that I was needing help on what’s the cheapiest manual transmission I can swap it too?
2. What all will I need or swap out to do a manual swap other then the transmission?
3. Cheapiest 4 speed transmission that will fit in the car?

please help thanks big time

 

Cheap & Buick don't feel warm together.

 

Yea lol I been seeing that I’m not wanting to pay like as high as for a TKX5 or that $4,000 5 speed or the 6 speed magnum for $5,000 lol can u get the old signaw or something Manaul I heard of it or wats the cheapiest 4 speed u know of? And is the T5 cheapiest and will it fit? And also isn’t that super turbine 300 transmission that’s on it now with a 455 isn’t that a way to small tranny? Will that tranny hold that much toqure and horsepower? It’s either the super turbine 300 or the other 2 speed auto but won’t that tranny blow up with that much power? Lol

 

Cuz I have the 455 with the I think super turbine 300 2 speed in my 1966 Buick skylark convertible wouldn’t that engine blow up that tranny?? Lol

 

The ST300 was used behind the GS 401, I'd have to check if it used more clutch plates for more hp capacity.
Best bet for a cheap 4 speed is a Muncie or good T-10. Saginaws weren't meant for high hp, neither were some of the later aluminum cased T-10's. T-5 likely isn't rated for a big block either.
There are some heavy duty 3 speeds out there like the early Dearborn and Muncie.

 

I have the 455 engine with the ST-300 behind it but that TS-300 tranny shouldn’t be able to hold that much power right I even have the Holley sniper EFI and mild cam and few more can’t remember but will that engine power from a 455 blow out a small tranny like the ST300?
And would you go with the muncie m20, m21, or m22?
And is the T-10 cheaper then Muncie or how much do each of them run around?
And would the 3 speeds ur talking about be on the floor or on the column and are they cheaper then 4 speeds?

and thank y’all for the help
Very new to the classic cars gas I’m usually
Doing the diesel preformance but always wanted to get one of these lol but thank you so much

 

And fit any Richmond manual transmissions in it??

 

You have a column shift Skylark?
Do you have a donor 4 speed car before you make the choice of tranny?

 

This is before I put on the Holley sniper EFI system also

 

Just to show wat it is and under the hood maybe to help

 

I haven’t found any donor cars and well I found one that ran but was way to expensive but just now found that the ad said it had a TB400 tranny is it I thought that Transmissions or read that transmission was a 3 or 4 speed transmission so is the TB400 transmission a 2 speed auto tranny? And if I have it does it have overdrive on it or is there a way or adapter u can install to put overdrive on that tranny? And is a TH400 do u know the max torque or how it can handle? And is a TB 400 easyer or cheaper to swap out to a muncie manual transmission? And would a car like mine need a M20 or M21 or M22? And off topic but has anyone had to change the light bulbs behind the dash cluster or the light bulbs for the speedometer cuz I have the bulbs they just came in but I keep looking and can’t find the wires or sockets that’s the light bulbs also and if anyone has a used muncie or used T10 manual transmission I could swap out let me know and if it is a TB400 would the bellhousing or the piece that adapts the transmission to the engine the same or what bellhousing or transmission adapter would i need to swap my 455 to a 4 speed tranny? Sorry so many questions and thank you so much for the help again

 

Thats one good looking motor if it runs like it looks!
A TH400 is a 3 speed and can withstand alot of torque and horse power.. Now the issue is the rear end. Do you know if its original to the car? If it is then you should upgrade, a posi is a must.
A 1966 GS or 1967 GS rear is a start or find a corporate 8.5 that were used from 1971 to 1972 on the GS's and 442's and GTO's. You won't need much gear with that 455, a 3:42 would be fine on the highway.
They have some bolt on type of over drive for a TH400 but I don't know how much at all about it..

Why the need for a manual overdrive is up to you but it won't be easy, even with a donor car.

As far as dash light bulbs, I think??? changing them is a project.

 

I never heard of a TB400 transmission, can't help you there.
The TH400 is popular for use behind a Buick 455. You need to find one from a Buick, Olds, or Pontiac (BOP) and not from a Chevy. The Chey uses a different shaped bell and won't bolt up. Also need to use a TH400 with the short 4" tailshaft, not the long tail that was in some big cars.
The TH400 is longer that your ST300 trans, you'll need to make new mounts for the crossmember and get a shorter driveshaft. Shifter needs to be modified or changed too.
Some guys are using a TH350 behind a 455. It's shorter, may be the same as the ST300 you have now?

You can add a Gearvendors overdrive to the automatic. Cost a couple grand tho.

A manual transmission swap needs a lot of parts. Pedals, linkage, z-bar and frame bracket. I used parts from a 66 Special with a V6 and 3 speed column shift. ^^^^ those parts would work fine for a 455 AFAIK. Even the V6 bellhousing will fit the 455. You will have to buy a Buick 400-455 flywheel, TA Performance has those. Also need a clutch and pressure plate.
You need to install a pilot bushing or bearing into the back of the 455 crankshaft. Do a search for posts, it's been discussed. Also see if your 455 block is drilled/tapped for the z-bar pivot. Maybe they all are? but I'm not a 455 expert.
As far as M20, M21, M22, it depends on what rear axle ratio you have and how you are going to drive it. M20 has a lower first gear and will work ok with a 3.08 (or so)-up rear. M21, M22 are close ratio and a higher first that needs a 3.36(or so)-up rear gear.

Do a board search for '4 speed swap' and read up.

You keep saying you want a cheap 4 speed and that's hard to do unless you find a whole setup somewhere. Otherwise buying all the parts could be a couple grand. A TH400 automatic is a great setup, could be done for a few hundred if you find decent used parts. A new short driveshaft could be $200 by itself.

 

Here's the rear of the instrument panel. The bulbs are in the plastic holders. Give them a quarter turn or so and the bulb comes out.

 

IF you stay with an automatic you also have the choice of a TH350. It's a bolt-in swap for the ST300. Driveshaft & all. IF built properly can more than handle what your 455 is putting out. Don't short change the 300 as it can also be built to handle the power. The next thing on the list would be to go to the 8.5 rear for mostly part availability.
Although the 8.2 was behind the GS cars & Stage 1's when new & seemed to hold up pretty well also.
Just my thoughts.

Tom T.

 

Thank y’all very much for the help
I’m starting to think that it is a TH400 sorry not TB lol so is there numbers and letter

ok yes I looked under at the tranny and those trannys both look almost close to the same so ig thats y I got them mixed up but yessir or ma’am the tranny is a TH400 not a ST-300 and thank you yes it runs amazing and with EFI kit on it now every time I hit the gas ig pills out alittle so much power I can’t not hit the gas small enough to just take off slow haha but ok the rear end I think looks maybe stock but it’s still somewhat black painted so might be newer but so can I change the rear end to a better gearing or something wer it’s less RPMs on the highway I haven’t got the touchscreen ran yet to the front yet so I can see the rpms but they sound high and also if I even maybe put even a like 700r4 4 speed would it gain power or lower rpms on Highway also and so the if I changed that could I get lower rpms on the Highway or would it be more power I just got into rear end gearing wen I was a semi driver like I liked anything from 3.42 to 3.90 but wen I worked for a mega carrier first they used like 2.87 or higher 2s to get better mpg but way less power in it I remember

 

Thank u very much sir or ma’am for the pic now I can finally see wer they are and wat they look like and so there the 7 little grey ones without wires going to them if so how do they get power without wires going to them and so they just turn alittle and pop out correct

 

also if it’s stock it’s not a gran sport is a skylark custom but what would it probably be geared at or if it was changed wat do u think they changed it too with a Buick 455 mounted to a TH400 tranny also

 

it turns out it’s a TH400 but so I would need to go to 8.5 rear end I only knew rear end sizes from like 2.78 to 4.11 I never heard of a 8.5 is that like a name of the rear end or like 8.5 bolt or something??