I have some old Pontiac engines 1957-63, and need to know exactly what year bellhousings will interchange between them. The old H-O racing manual says 1961-64 will interchange. I was also told that 1955-60 will interchange, but not exactly in car, just that they will bolt on to engine. Yesterday I was told that's not necessarily true, because the dowel pin size and bell to block bolt size changed in 1963, it got smaller. also, the way the transmission is clocked on the bellhousing changed, because a T10 trans would it the floor on a Catalina, if the trans was mounted level against the bellhousing. So the trans bolt pattern is clocked to the driver's side at 11 o'clock. Then in '64 the bell was not clocked as much. Is this true ? Anyway I have four complete 389 engines, '60, '61, '62, '63. all were 2 bbl except one, the '61 was a 4-barrel 303HP. I also have 4 early engines, a '57 GMC with manual 11" flywheel/clutch but no bell, a '57 347, and two '58 370's. most of these still have the automatic transmissions still on them. I'd like to know what bellhousings, either oem or aftermarket, would make them useful to drop into a car and run with a 4 speed trans, or even a 3 speed trans. I noticed the bellcrank connection on these old engines is not on the block like the late model Pontiac V8, it's on the bellhousing instead. this moves if further backwards in the car, if swapped into a 1965-up late model Pontiac stick car. What's the easiest way to fix that problem ? I have been told the rear transmission mount on the early Catalinas was special, a clamp on mount to the rear tailshaft of the trans. and the regular 2 bolt mount will not work, due to the way the trans is clocked to clear the tunnel. if swapped into a late model, what's the easiest way to address that issue ? all replies welcome.
I made my crossmember to accept the clocked transmission. It's hard to get complete factual full specifics on Pontiac stuff. I have a standard bellhousing from a 64 big Pontiac. It's different from any other bellhousing. It takes a big Pontiac specific starter and there is no such thing made now. We had to basically make ours. I have since found some factory rebuild parts. Your early bellhousing will be tunnel mounted with side mounts. While they are out there finding a bellhousing for your 57 is not an easy thing to do. Finding manual anything for the early Pontiacs isn't easy to do. The early 389's are pretty sought after. Your easiest solution to putting a Pontiac in a 65 or later Pontiac is to sell some of the old stuff and buy the newer stuff.
so...the 1961-63 starter, is different than the 1964 starter ? I can get a 55-57 bellhousing, but only can be used with the old 3 speed transmissions, with small front bearing retainer. what bellhousing would be most useful across the entire spectrum of engines, 1961-64 ? would a 1961-62 bell, fit and work on a 1963-64 engine ?
In 1964 Pontiac slightly changed the block and went to block mounting with the GTO. The starters on the standard big Pontiacs remained mounted to the bellhousing. But because of the change to the block the bellhousing, flywheel etc are one year offs. From what I understand unless you are restoring a car you can put the 61-62 bellhousing on the 64. Well, you still can but it won't be factory correct. I was told I could try and find the right starter or go to the earlier stuff on my 64 389.
You should try to contact Steve Barcak. He is a major Pontiac guy. He goes by Applekrate on here I think but he’s not on here regularly. He has a website, I think it’s Pontiac Heaven. He may be able to answer all of your questions and direct you to the parts you need. If you need to stick with factory parts you may be in for a lot of searching. If you don’t care, look into Quick Time bellhousings and Wilcap for flywheels and adapters.
Regardless of where the 64 389 blocks were used, the ones installed in the big cars had the block drilled & tapped for the block mounted starter even tho they actually used the bellhousing starter mount.
Fred Teufert has a useful Pontiac page that includes a section on parts interchange: http://www.teufert.net and http://www.teufert.net/pontiac/inter.htm
In 1961-1964 there were short tail shaft and long tail shaft transmissions. Catalinas, Venturas, Grand Prixs used the short tail shaft, and Star Chiefs and Bonnevilles used the long tail shaft. The short tail shaft mount was a weird clamp on mount, it was kind of like a big muffler clamp. The long tail shaft mount was more conventional in design, with two bolts to the transmission and two to the crossmember. My Bonneville has a four speed, but to be honest I've never noticed if the transmission was clocked off of straight up and down...I don't think it is.
They did have the blocks drilled for a starter but it's a different starter for the big Pontiac standards.
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