My fan runs very close to the top of the fan shroud (about an 1/8 inch) yet has over an inch of clearance at the bottom. Someone told my that the core support bushings may be sagging. Any ideas on how to fix?

You'll throw all your body panels out of alignment if you only fix the core support.

Instead, try to shim up your shroud a little bit, and you can also put washers under your tranny mount to raise the rear of the tranny, and hence lower the front of the engine. Worked for me.

What kind of vehicle?

Maybe you need a new OR taller transmission mount or shorter motor mount frame stands.

On 68-72 Chevelles if you use 307 frame mounts with 350/BB engine mounts it will make the fan sit too high in the shroud.

There are small block fans shrouds and big block shrouds. The big block uses a 18 in. fan. The small block an 17 in. fan. I believe an 19 in. fan is from a pickup. Is the shroud centered? How much clearance at the bottom?

You'll throw all your body panels out of alignment if you only fix the core support.

Thats what i thought too!

What kind of vehicle?

68 el camino

On 68-72 Chevelles if you use 307 frame mounts with 350/BB engine mounts it will make the fan sit too high in the shroud.

Very interesting!! It used to be a 307/glide car, now 383/350. I've never heard of diferent frame mounts before. Are the frame mounts shorter?

On 68-72 Chevelles if you use 307 frame mounts with 350/BB engine mounts it will make the fan sit too high in the shroud.

And mess up your drive line angles...

Very interesting!! It used to be a 307/glide car, now 383/350. I've never heard of diferent frame mounts before. Are the frame mounts shorter?[/quote]

Yes, there is a different engine "tower" for the 307 than the 350. I believe the 307 is shorter.

I have a scan of the different part numbers for the mounts and their brackets below. They are for the Camaro and I don't know if they are valid for a Chevelle.

I had to get a set of the 350 brackets when I went from the 307 to the 350 to get the drive line right.

Experience is a great teacher.

Ron

Changing the frame mounts is a PITA, the best option for you is probably to buy a pair of Energy suspension polyurethane engine mounts (the 307 style) as they are much stronger than the original 307 ones. You about need to have the lower control arms off to change the frame mounts. The 307 frame mounts are taller than the BB ones, plus a hair wider. Did you have trouble getting the engine to sit all the way down on them?

Dave

You guys are the best! Thank you! I've never had a problem setting the engine down on the frame mounts, but I've been dealing with the fan/shroud problem for a long time. I never suspected different frame mounts for one smallblock to another. 68-72 will all be the same right? As far as poly engine mounts go, do they transfer more engine vibration? I'm tired of the rubber mounts breaking anyway & will definatly consider them. Thanks again, B

Brian,

I've been told (and am in the process of trying it) that I would have no vibration problems, but will solve the torque problem of breaking the mounts, by going to a solid mount on the drivers side, but sticking with rubber mounts on the pass side and tranny.

Yes...for some reason...GM made special mounts just for the 307. If you put a 350 in an original 307 car with 350 engine side mounts the frame side towers will make the engine sit to high in the front (the 307 engine mounts are also a little lower in profile). Also...the 350 engine side mounts will not fit over the 307 frame side towers, but they are very close...that you can think something is wrong with your mounts and modify them slightly to fit. I found this very thing out the hard way!

Easiest fix is to buy 307 engine mounts. More extensive fix is to buy 350 frame side towers and swap those out.

Correct me if I am wrong, but if 307 mounts are lower, why would that make the engine sit higher?

307 mounts are taller because the engine mounts are thinner. BB/350 mounts actually sit lower

Yeah...that is what I was saying, but it apparently wasn't too clear. The frame side towers are taller and the motor mounts are thinner...at least if I am remembering correctly from my experience with that issue.

Oh, ok, thanks guys.