Hi , Ive got two bellhousings for early chevy now, but one is with undrilled centerhole, and the other is with a hole! Can u tell me the difference? The "stock-drilled" bellhousing; Casting # 3704922 and date "plate" # 35 and a D on other side. Couldnt get the pic on web, im trying.. Cheers!
Tumbleweeds, my experience is that the early bell housings had the center hole drilled and the later didn't. I am wracking my brain and I don't recall any 283s in the '60s using the center top hole. Someone else more studious than myself will be able to give you the definative answer. I dr remember pulling the bell housing and transmission from a '58 Corvette that had the boss but no hole where the center top hole should have been but we always chocked that up to a mistake at the factory. If you cannot upload your pics you can always E-mail them to me, you should be able to do that from my profile. There that will get them started.
I think having, or not having, a center bolt matters not. The load at that point is compressive, the bellhousing pressing against the block in normally mounted position. It's the two verticle bolts on each side that do all the hard work. The only reason I can think of to concern oneself with this issue is if you are doing a "correct" restoration. Ray
I believe when Chevy went to side mounts in 58 they discontinued boring/threading the center hole, I do not remember ever seeing a post 58 Chevy motor with the hole threaded.
Terrible, I did rebuild a '59 motor that went into an El Camino, it had the top hole drilled and tapped. I put a later auto in it when I ***embled the car so I didn't use it. Maybe it has to do with what time of year the block was ***embled or what it originally went into.
I would have to dive into my bellhousing pile to see what has the top hole and what doesn't if I thought it had some worth. Unless you're restoring a 100 point car, who is going to see if its there or not? Bob
been to any Corvette Club shows lately? They'll beat you up if your OEM hose clamps are not "clocked" properly. I bet they have a guy that just loves to stick his hand back there looking for that yes/no bolt. dj
3704922 '55-'56 Cast Iron 10.5" clutch 168 tooth flywheel (1st. SBC bell housing) One thing that's different is the way the starter is mounted. On one the starter was drilled and tapped for the 3rd (outboard) bolt, and the bellhousing had a plain hole - and the bolt went in from the bellhousing side. On the other, the bellhousing had the tapped hole, and the bolt went in from the starter side. I have found the top hole tapped on the 55-56 cars. The change was 1955-56 vs. 57, maybe the change was made in late 56?. So you have to make the starter match the bellhousing. The later Chevy trucks are much the same and have mounting ears. My '55 has a Chevy truck bell housing.
The load at that point is compressive, the bellhousing pressing against the block in normally mounted position
I thought the truck blocks/ bells were drilled not the p***? I dunno? I have 2 truck blocks both drilled and tapped Chev II not drilled
The black and white pic is an early 1955 265 and the color pic is a mid year (may or june) 1957 283 that was still staggered bolt valve covers. Both have the threaded hole. 283 was a powerglide, i still have the adapter. Sent from my Droid powered Samsung Galaxy S
An ebay looksy turns up that the Corvettes bellhousings had the top center hole in them. Theres a bunch on there now, take a look http://www.ebay.com/sch/i.html?_odk...m570.l1313&_nkw=56+chevy+bellhousing&_sacat=0
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