I have the traditional 70 GS Clone with the 455 th400 combo.Im thinking of going the 4 speed way.I know its a lot of $$$, hard to find part and lots of work to achieve.Theres lots of thing I know about it (reading throught this forum) and lots I dont! I know that if I do it, I would want it to be done right as much as possible, as my gs is completely stock, and I would like to have it with the center console and the right hurst shifter and everything! I was wondering if I will need to change my driving shaft??? (shorten it or lenghten it) And if you got any other comments, advices, go aheads if you wanna share it!!!! Thanks!! Marc
same size driveshaft if the car was the 455/400. When I converted my 70 cutlass to a 4 speed i compared the driveshaft to the one in my 70 skylark 455/400 and the lengths matched. both however were originally longer as they were 350/350 driveshafts but to answer your quest, u shouldn't have to touch the driveshaft. Allen
Sorry, but I believe allioop is wrong. I converted my '68 GS400 from TH400 to Muncie M21 and had to replace the driveshaft. If you had a 350 you wouldn't, but with a big block, you do. In the 400/TH400 combo, the driveshaft is too short. While we're on the subject, you'll have to move the crossmember forward too. This makes it necessary to use a different emergency brake cable as well as the hook it rides in from the crossmember. This seems to be something that is never mentioned when people talk about these conversions, but is just another one of those things you'll need to do.
Yup I may be but I was using a super t10 tranny, haven't compared the length to the muncie but I do know that the driveshaft in my 455/400 skylark is the same length as the driveshaft in my 455/st10 cutlass. Both driveshafts were from 350/350 cars and had to be shortened. so right now i have a shaft in the auto and one in the 4 speed that are the same size. allen
Ok, that makes sense. I don't know about T10's, but since he said he wanted it as stock as possible, I figured he would be using a Muncie. I did mine like he wants...all stock. But an overdrive would be nice. I find myself wanting to shift even though I'm already in high gear! ou: Hard to get used to when all cars today have overdrives and cruise at much lower rpm's.
Are you saying that a shift from a 3 speed automatic trans th400 to a 4 speed (muncie or t10) wont drop the rpm on the highway in 4th speed???
ok, ok ok,.....so.....normally, if its an automatic (th400) and you want an overdrive (while staying with an automatic) you go the th200r4 normally, there aint no other/simpler choice , right?! But if your manual (muncie 4speed..m20,21 or 22, they are all 1.00-1.00 in 4th) and you want an overdrive gear , you got what? ...............richmond got 5 speeds with no overdrive, I guest that you need to change the axle to a 273 gear to get good use of the 5th 1-1 speed.........?????????? and im not talkling about 6 speed trans and tremec, cause they are way out of my budget
The Richmond 5 speed let's you use a 2.73 rear end ( good highway rpm) for example and still rip hard in the low gears, so it has a really low first gear,e tc. Or you could use a higher geared trans 200-4r with a 4.10 gear and pull really hard and use overdrive for a good highway rpm. Two approaches to the idea of quick low gears, and decent cruising rpm.
yeah Abe!!!That looks like it, exept that in the 200r4, your still styuck with an automatic trans.....richmond with 2,73 sound good!
Just got my '71 Riv up and running with the ST10 swap. I do notice about a 100rpm drop at 70 mph in 4th over the TH400 AT at same speed. I imagine that's due to inherent converter slip since it wasn't a lock-up type.
Installed the richmond 5 sp. with a friend in his 66 chevelle. Has a 2.73 (i think) rear, w/posi. THe trans really pulls in the low gears and can cruise all day at 65mph. The only problem we had was modifying the crossmember to fit right.
ou: :idea2: here's a bunch of reasons why " I " wouldn't even think about converting to a 4 speed.....uzzled: uzzled: most people don't have clue what there getting themselves into...:error: ou: http://v8buick.com/showthread.php?t=57004&highlight=launch+speed
yeah........im thinking of sellin the car and getting one with already the 4 in.....this trans swap would cost way too much....and I would like a black car+black interior.......but im afraid that if I sell the car I wont buy another....being that I am 24 and poor and have no futur..... or might get lost and buy a 77 4 speed trans am SE.........(project or not),,,,,,,,,,,,ou: Man......my car is A1 running and im unhappy!!ou: My interior is fine but its white and id like it black, the exterior paint is like a 8/10 (glacier white) but I would like the car Black, and I got the th400 and want a 4 speed!!..........:ball:
I did it to my car. By the time you get all the parts and rebuild/refinish them, you will spend at least $3,000. Add in about 20-30 hours of labor to R&R. However, it is totally worth it......:TU: The easiest way to to get a donor car with all the parts on it.
Wow I converted my 65 Skylark to 4 speed for less than 400.00 including the muncie trans that I had to put back together but it was free.If you look around you can do stuff on a low budget if you are patient.I realize a 455 in a later one may present a few more problems than I encountered but I would think it would not be much of a differance doing the swap.Since your car is already a clone anyway I would do it.Just take your time collecting parts and when they are all aquired do the swap.Patients will save you alot of dough. I of course had the 2 speed original auto trans that I really did not like but I am thrilled with having the 4 speed.The fun differance is astronomical.I do not go drag racing but it is very fun just to drive around the streets.................
Stuff you need: Tranny Bell housing Flywheel Pressure plate Clutch disc Throw out bearing and arm Trans mount Shifter mechanism/rods/clips etc. Shifter handle/knob Floor hump Boots Driveshaft Neutral safety switch Pedals/pads Push rods Bolts, fasteners, etc. Speedo cable Console The clutch parts were $400 Rebuilding the Muncie with new M22 Masiero gears was $950 Rebuilding the Hurst shifter was $175 Rechroming the handle was $90 New driveshaft was $300 It adds up fast. I rebuilt everything, and used all GM parts. You can do it cheaper for sure, but not better.....
