Jan I just installed a 462 BBB in my original 71 GS350 4speed car. I even utilized the original clutch linkage. This car is only being driven on the road and not raced so the 350 clutch linkage and stock 11" AcDelco clutch was utilized. See attached photos. George
Assuming we are only considering BUICK parts, and the car is already set up for a manual shift transmission and 455 engine and the only question is about a using a manual shift transmission that came from a BUICK 350 engine set up, only a couple things needs to be considered. If that is the case, skip the middle paragraph and go directly to last two paragraphs. If this is not the case, see the next paragraphs. If this car is set up now as a BUICK 350 engine with BUICK manual shift transmission, there is plenty to do for the BUICK455 swap into the 350 car. We can point you in the right direction to get information. BUICK bellhousing is needed no matter what you are doing. The transmission either Mucnie or Borg Warner should generally interchange but do have slight variances depending on the year of the transmission and the year of car, shifter, etc. Shift shafts in the tranny vary and need to be correct for the linkage you are using. If you are trying to convert the car from an 350 engine with a automatic transmission to a 455 engine with a manual shift, you have quite a task at hand and we will need to point you to other information to get you started. If the car is already set up for 455 and manual transmission than it is not too bad at all. You have most of the moving parts for clutch and the floor hump in the trans tunnel, speedometer, manual shift steering column, maybe back drive 1969, 1970-1972, and neutral safety switch if 1970-1972. You will want the 455 style bell crank (z-bar), clutch fork and rod which are available. The small block style may work, I think I have seen it on a big block car once but not certain. These are listed as specifically different parts for the application in assembly manual. You also need to be sure your shifter and linkage are compatible to the transmission style and year. You need to inspect your 455 first. Is it already built for a manual transmission? It should have a manual transmission flywheel that was balanced with the rotating assembly or was matched to the flex plate if an afterthought. Also, the 455 block needs the machined portion, drilled and tapped for the bell crank (z bar) stud. The factory did this on most blocks until 1976. You also need to be sure to have a pilot bushing in the crank shaft for the transmission spline. Most cranks are already bored and concentric but you should verify also. If you are in need of any of the above, we can point you in the right direction to properly get where you are looking to go. Hope this helps.
Okay, here is some more info. I have just bought a original 70 GS 350 with 4 speed. Engine is rebuild and same is trans with centerforce clutch and parts and lakewood blowproof bell housing. The 455(464) I will put in it is not set up for manual trans, is in my conv. now with th400 on it. Do any of you guys come to BG then I might could ask you some more questions and write down what to do and get for the swap:grin: Thanks so far for the info. Jan
I will be at BG. I've been driving a 70 GS 455 convertible for 20 years. I've had various combinatins in it and raced it for 13 of those years. Look me up. I'll be running a white with green GSX stipes hartop. Dave
I've always wondered if you could make a 4-speed from a Skyhawk live behind a 350 or 455. I was going to try it once, but I got talked out of it and sold the car (Roadhawk). Cool thing about that 4-speed was there wasn't any Z-bar, or anything external to worry about. It was all cable operated and enclosed.
The 4 speeds in the Skyhawk were Saginaw transmissions. They are ok for a V6 and a mild 350 however the 455 will grenade them in a hurry under hard use. They will survive dehind a 455 if driven easy. I have broken a few Muncies due to short shifting such as power shifting around 3000 rpm where the 455 makes a lot of torque. I have not broken them when shifting at WOT & above 4000 rpm. If the original transmission is in the car it will be a M-21 muncie therefore a Buick muncie is a muncie whether it was behind a 350 or 455 they are the same. There are 3 modeles of the muncie M-20 weakest, M-21 (factory installed by Buick) and the M-22 aka rockcrusher. See you in BG next week.
