Big Block Engine mounts

[L78Kiwi]

Hello I am looking for a little advice. I am fitting a 69 L72 427 to my 67 L78 Camaro

From what I can gather there is a different between 67/68 Camaro BB frame mounts versus 69. Is this correct?

If so what is the correct mounts to use 67/68 or 69?

[Lee Stewart]

This should help you:

http://www.camaros.org/engine.shtml#EngineMounting

[L78Kiwi]

Hi Lee, Thanks for the response. I have read this and as I thought there is a difference in the mounts between BB 67/68 vs 69. However the advise on this site is not quite definitive to the problem I am seeing.

With the current 69 mounts on a 69 L72 engine the sump fails to clear the steering connection rod which runs parallel to the main cross member. Also the transmission mount from the gear box is positioned forward of the transmission cross member by about an inch

This leads me to assume the engine (with the current 69 mounts installed) is sitting too far forward on the frame

So my question is, does the 67/68 BB mounts position the engine further back on the frame?
Regards Gavin

[bbbentley]

Gavin, I would like to give you a definitive answer, if only I could? I am not sure I will be able to help, but will tell you what I do know. I have no real 67 bb experience, I have, though, messed with several 68 & 9 bb Camaros. The cross member is the same whether manual or TH400 for an 68 & 69. This would tell me that the mount positions would (should) be the same. The main difference as I understand (and I'll be corrected if wrong) is the 67-8 mount is narrower for a different engine mount than the 69. I also understand that the 67-8 driveshaft is a little longer than the 69? I never quite understood exactly where that length was achieved , but I never questioned it either, I just accepted the fact? But since the cross members are the same and subframes interchange, I have to assume that the driveshaft length difference is due to the rear and where the springs are positioned on the frame rails, because the rails are different between the years? Regardless, irrespective of the engine date ( you said you have a 69 engine) I would use the mount called out for that year of car that it is supposed to have, i.e. Use the 67-8 mounts on your 67.

[plum67]

67 & 68 396 frame mounts move the motor about 1 " forward. That's why they have a longer driveshaft. You said you have a 67 l78 already so the frame mounts should be correct. the correct bb frame mounts just hang over the back edge of the frame while sb's hang over an inch or so. Just buy 67 302, 350 or 396 motor mounts and the motor will set correctly. Sounds like you also have a small block crossmember. If the crossmember has an oval opening where the bolts are then its a small block one.

[bbbentley]

"67 & 68 396 frame mounts move the motor about 1 " forward. That's why they have a longer driveshaft".
Curious? Do they have a 1 in. offset tranny mount? Because the trans. cross member is the same and in the same place on all bb.s, right?

[plum67]

yes big block is a different cross member than small block

[L78steve]

Its possible the 67 and 8's are 1 inch forward. Just have to use the second set of holes in the frame for the cross member. Being that the shorty water pump is used the engine has the room to move forward. The other benefit is not having to crunch the valve cover on the driver side as in 69.

[L78Kiwi]

Hello, Thanks for all the responses. The sub frame is a small block frame.

Let me give you a little history. The Camaro is a genuine 4K car it has not been on the road since 1970. The first owner had an accident which destroyed the front end. The second owner used the car for parts and the third owner began restoration. The third owner used the frame and front sheet metal from a 327 car.

I am the forth owner. I am trying to restore to the car as close to factory as possible....the 427 was the closest I could get to the original (rare as rocking horse s&*t) 396 engine.

So if I am correct the summary of the above would be that I need to take Plum67 advice to get a suitable fit?

I just want to clarify, when you say the cross member for a BB car is different from a small block car, are you talking about the front subframe assembly (as inclusive of front suspension etc) or the cross member for the gear box?

So just to really make you all roll your eyes.....and think what the!

Because of the engine change I also decided to use a Tremec 5 speed. This was supplied with a gearbox cross member. Ordered for a 67 BB car

So as I originally said, with the current 69 motor and frame mounts the engine is sitting forward on the frame to the point where there is not enough clearance between the back of the frame cross member and the sump to allow the steering arm to fit between. The gearbox cross member is also sitting behind the isolator mount on the gear box by about an inch. In summary it looks like if I can shift the engine back on the sub frame by about an inch I will get the engine to fit with enough clearance for the steering and line the isolator up with the gearbox cross member. Given this it seems logical to assume the engine mounts are the problem

But given the additional information will Plum67 solution still work? If so is there any other possible clearance problems I need to be aware of such as engine to firewall or engine to radiator ? (I do have a short water pump)

Thanks again for all the advice so far and I look forward to your further generous assistance

Regards Gavin

[plum67]

you need to start from the beginning and that means installing 67 68 frame mounts because not only do they move the motor forward they also move it over the right. The orig. big block trans cross member does the same thing too. So big block cars have the motor and trans off center for clearance around the steering boxes. That's why the clutch Z bar on these cars is longer too. Nothing will fit right if you don't start with the correct set up to begin with. After you get all these parts get installed then if the sump ( I think you meat oil pan ) should fit unless you have something wrong there too