View Full Version : Big Block Engine mounts
L78Kiwi
05-21-2017, 08:15 AM
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
05-21-2017, 10:32 PM
This should help you:
http://www.camaros.org/engine.shtml#EngineMounting
L78Kiwi
05-22-2017, 07:51 AM
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
05-22-2017, 11:14 AM
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
05-22-2017, 01:47 PM
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
05-22-2017, 03:46 PM
"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
05-22-2017, 06:19 PM
yes big block is a different cross member than small block
L78steve
05-22-2017, 07:10 PM
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
05-22-2017, 08:38 PM
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
05-22-2017, 09:24 PM
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
bbbentley
05-22-2017, 09:30 PM
Gavin-no such thing as a "small block" frame. There is a web site, camaros.org that will give you the education (without tuition) you need so that you may learn what will give you an accurate restoration.
(rear)crossmember- as in the piece that unbolts from the rear of the subframe and holds up the transmission.
Good luck
Lee Stewart
05-22-2017, 09:34 PM
http://s21.postimg.org/eoecda71z/trans_xmember_sb_bb1.jpg (http://postimage.org/)
[/url]
SB (Top) vs BB (Bottom) Cross Member 67-68 Camaro
http://s8.postimg.org/6sgxilzyt/1051y_1.jpg (http://postimage.org/)
[url=http://postimage.org/]
L78Kiwi
05-22-2017, 09:59 PM
Thanks again for your help. I will order a set of 67-68 frame and engine mounts and then progress through the other required parts.
From the advice I think I need to take a closer look at the oil pan. From what I can make out there should be no difference between a 427 L72 and a 396 L78 oil pan? Unless the oil pan has been modified......would anyone know of any common modification which would affect the clearance of the oil pan to the cross member?
Regards Gavin
Lee Stewart
05-22-2017, 10:23 PM
http://s7.postimg.org/757ygodh7/EP_173.jpg (http://postimage.org/)
[/url]
AFAIK this is the oil pan you should be using - BB Camaro. Does yours look like this? Or does it look like the one below?
http://s11.postimg.org/8zfqv6adv/large_egp_1516.jpg (http://postimage.org/)
[url=http://postimage.org/app.php]
L78Kiwi
05-22-2017, 11:53 PM
Thanks Lee, from what I can see the oil pan I have looks like the first image. But the drain plug on mine is at the back. I suspect it had been moved as when it was stripped it had been brazed in the new position
Lee Stewart
05-23-2017, 12:32 AM
http://s24.postimg.org/ltiptaph1/vvv.jpg (http://postimage.org/)
[/url]
http://s9.postimg.org/ogbqhymtb/image.jpg (http://postimage.org/app.php)
http://s9.postimg.org/6ex6xwi67/ddd.jpg (http://postimage.org/app.php)
[url=http://postimage.org/app.php]
1967 396 Camaro SS with 4 speed
plum67
05-23-2017, 12:52 AM
That's a small block cross member installed backwards
Lee Stewart
05-23-2017, 02:25 AM
That's a small block cross member installed backwards
Is that right? Oops!
How about this one - supposed to be an L78 396 4 speed in a 1968 Camaro:
http://s26.postimg.org/7ynxzrjah/1qa.jpg (http://postimage.org/)
[/url]
http://s26.postimg.org/fsojl5r3d/werf.jpg (http://postimage.org/)
http://s26.postimg.org/oc7xiwzft/bbbb.jpg (http://postimage.org/)
[url=http://postimage.org/]
bigsixman
05-23-2017, 02:39 AM
Second set of photos is mounted ok.
L78Kiwi
05-23-2017, 08:55 AM
Hello here is some images. I think in comparison to the images posted the oil pan might be over sized?
L78Kiwi
05-23-2017, 09:36 AM
this is probably a corvette oil pan
L78steve
05-23-2017, 12:18 PM
It is a Vette pan. Wont fit.
cook_dw
05-23-2017, 01:00 PM
My preservation thread on my 68 L78 but the pan is the same.
http://www.yenko.net/forum/showthread.php?t=133473
http://i1310.photobucket.com/albums/s649/cook_dw/1968%20Rallye%20Green%20L78%20Camaro/IMG_4759_zpsknpbuk5n.jpg
http://i1310.photobucket.com/albums/s649/cook_dw/1968%20Rallye%20Green%20L78%20Camaro/IMG_4764_zpsw4vogv3k.jpg
L78Kiwi
05-24-2017, 08:01 AM
I guess I now have 2 problem identified
1. engine mounts
2. Oil pan (or sump for us outside the US)
The only problem left to solve is the gearbox cross member. Anyone have any ideas on this?
Lee Stewart
05-24-2017, 10:37 AM
I guess I now have 2 problem identified
1. engine mounts
2. Oil pan (or sump for us outside the US)
The only problem left to solve is the gearbox cross member. Anyone have any ideas on this?
You might want to get in touch with Tremec seeing as how you are going to use one of their gearboxes
Here is their website - they have a CONTACT US "button"
http://www.tremec.com/
L78Kiwi
05-25-2017, 08:01 AM
thanks Lee, will do
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