BBC mounts.. how the do these things fit on? or am i just that dumb?

[smoknbarrels]

I am sitting here looking at my BBC perches, I bought both left and rights from GM, and I am trying to put them onto my '67 which originally had a 6 cyl engine in it... but the problem is that they don't line up any logical way.? the only way i can see them fitting is if I put them on the two front holes and notched the frame..? I can't imagine this is correct? should I be cutting the frame rails?

can anyone confirm how these things should be put on?

thanks..

[Longhorn Man]

You may have to do some mods... there was no BB option in 67, and they made modifications to the frame in order to offer it in 68

[smoknbarrels]

using a ballpark eyeball measurement.. looks like I'd have to trim off about a 1/4" of material where the mount connects to the frame rail..

anyone have a photo of this spot, it sure would help out a lot! i'll keep searching the forum in the meantime..

[chevy72blu]

Are you talking about trimming the upper frame rail? I would make my modifications to the tower rather than the frame if at all possible. If you have power brakes, mock the motor up on the stands and make sure you can get your valve cover off the driverside bank beneath your booster. Other than that, you can pretty much set it however you like. If you can take a pic, I can probably give you a little more direct advice.

[71tahoe]

Not a recommendation but an observation.

GM engineers designed the 68 frame and they have lasted 40+ years too.

I believe the lateral strength in your frame will be behind where the motor mounts attach. Directly above the crossmember, there is not much additional strength 1/4" will add. If someone can supply a dimension on a 68 frame don't trim less than that and don't leave any sharp corners. Those aren't all the don'ts but the biggies.

[Longhorn Man]

I'd trim it personally.

[smoknbarrels]

Whelp, I got tired of staring at it for the past few days.. so I notched the top part of the frame rail 1/2" .. I just couldn't see any other way that they could fit on..
there is still plenty of meat left between my notch and the top three mounting holes (which i only need the front two of).
I'll try to get a pic in the next day or so, of what I did..

[caminokid]

I guess I dont have to worry about mine then. Since I changed the engine cradle and front suspension to the 87...I should be able to drop the 454 right in.

[Longhorn Man]

yours is a 69, they came stock with BBC.