CRG Discussion Forum

Camaro Research Group Discussion => General Discussion => Topic started by: SS396 on March 06, 2009, 12:23:07 PM

Title: BB 396 sits to low in 68 Camaro
Post by: SS396 on March 06, 2009, 12:23:07 PM
I've put a 396 engine into a 68 Camaro using repo engine frame mounts purchased from classic industries. They are stamped with numbers 3912597L and 3912598R which are supposed to be correct. I'm using new original motor mounts 6258154 so I assumed everything was right. The problem is the motor sits way to low, the fan hits the bottom of the shroud and the front section of the sump nearly rests on the subframe. Has anybody got any ideas as it's driving me crazy. Something is wrong somewhere and I can't figure out why.
Title: Re: BB 396 sits to low in 68 Camaro
Post by: william on March 06, 2009, 04:45:31 PM
I believe you have 69 and later motor mounts. They are wider and thinner than the earlier style and will fit earlier frame brackets. If the mounts were an easy fit on the frame brackets and there is a gap you have the wrong mounts. Mounts are supposed to be a tight fit on the bracket.

I assume you have a correct BB frame crossmember.
Title: Re: BB 396 sits to low in 68 Camaro
Post by: SS396 on March 07, 2009, 03:38:25 AM
These are the correct part numbers for the frame mounts and motor mounts for a 68 camaro with BB as per the following site. That's why I can't work out why motor sits so low in subframe. http://www.pozziracing.com/camaro_engine.htm
Title: Re: BB 396 sits to low in 68 Camaro
Post by: william on March 07, 2009, 02:27:49 PM
With all due respect to Mr Pozzi I still believe you have the wrong mounts. His info could have been incorrect. For years everyone thought they all interchanged. I had exactly the same problem with a '69 Z/28 many years ago and that was the solution. With the correct motor mounts you can put a bb on sb frame brackets-that's what Yenko/Nickey/Bill Thomas did in converting '67 427 Camaros.

I assume the 396 has a 4 quart pan. If it is the truck/B body/Corvette 5 quart it will not work.

Title: Re: BB 396 sits to low in 68 Camaro
Post by: L78 steve on March 07, 2009, 03:51:20 PM
I have a 396 in a Nova with all the correct pieces and the sump is barely off the frame and the shroud needed to be pulled back at the lower side with a wire tie until the plastic set in the proper shape .
Title: Re: BB 396 sits to low in 68 Camaro
Post by: SS396 on March 08, 2009, 04:19:29 AM
William, the motor mounts I'm using are genuine GM 6258154 and the instructions inside say that they are correct for a 68 Camaro with 396. There are no gaps when fitted to frame mounts. I've tried to fit 69 motor mounts to my frame mounts but the 69 motor mounts are too narrow and wont fit over the frame mounts. Does anybody have the base to centre of hole dimensions of their frame mounts LH and RH side in a 68 Camaro with 396 in which the motor sits correctly.
Title: Re: BB 396 sits to low in 68 Camaro
Post by: william on March 08, 2009, 03:13:01 PM
Are the frame brackets different heights? The LH BB bracket is taller than the RH to offset the engine to the right. Neither bracket is the same as SB.

Title: Re: BB 396 sits to low in 68 Camaro
Post by: SS396 on March 09, 2009, 03:37:41 AM
William, yeah the brackets are different heights. As I said in the first post I bought these at classic industries and according to their books these are the correct ones for a 68 with BB. Maybe I'm wrong but it just seems to be too low to me, the carby does not sit level, it's low at the front.
Title: Re: BB 396 sits to low in 68 Camaro
Post by: Marty on March 10, 2009, 06:03:35 PM
What transmission and how is it mounted? Is it mounted too high in the back? I have a 68 BB with the Classic Industries frame mounts and it fits fine. Martin
Title: Re: BB 396 sits to low in 68 Camaro
Post by: SS396 on March 10, 2009, 10:55:23 PM
Marty, the car was originally a small block. The tranny is a turbo 350 with the original crossmember. It's always been in the back of my mind that this could be the problem as you stated, that the tranny is too high and is therefore lifting the front of the motor down to much. Does anybody know if this the cause of the problem for sure and if so how do I solve it? Has anyone done this engine swap with a turbo 350 and found the same problem?
Title: Re: BB 396 sits to low in 68 Camaro
Post by: hotrod68 on March 11, 2009, 04:11:43 AM
The Turbo 350 and 4-speed mounts are all the same--I can't see the transmission mount being the problem unless you used a urethane transmission mount. I've had problems with urethane mounts being too tall and causing transmission tunnel clearance problems, but never so bad that they tilted the engine that far downward in the front. You'd notice a misalignment in the driveshaft/rear axle angle if it was that bad. A bud and I once swapped a 396 into a '69 307 Camaro and used the original 307 frame and engine mounts with no problems whatsoever. I believe that by some glitch you have the wrong frame mounts, whether via wrong part# or a bad repro parts run. Do the repro frame mounts appear taller than the original mounts? I'd check the mount through-bolt height and go from there. This is a strange problem indeed. Good luck!
Title: Re: BB 396 sits to low in 68 Camaro
Post by: Hatman on March 11, 2009, 01:17:49 PM
Since when were the turbo 350 & the B.B. crossmembers the same?
Title: Re: BB 396 sits to low in 68 Camaro
Post by: SS396 on March 11, 2009, 01:44:11 PM
As I was saying in my earlier posts if I could get the correct measurement from base of frame mount to the centre of the bolt holes on both the RH and LH side this would stop all the guess work. Maybe my repo frame mounts are the result of a bad batch run and aren't right. If any members have an original 396 engined camaro and could take some measurements for me that would be greatly appreciated. As I also said the engine mounts are genuine GM and correct for a 68 camaro with 396 so the problem has to be with the frame mounts or tranny crossmember.
Title: Re: BB 396 sits to low in 68 Camaro
Post by: Marty on March 11, 2009, 10:58:57 PM
I still have my original GM frame mounts. I put them on a table and measured to the center of the bolt hole.

3912597, 2 5/16"
3912598, 1 7/8"

These are eyeball measurements but are pretty close.

Martin
Title: Re: BB 396 sits to low in 68 Camaro
Post by: SS396 on March 13, 2009, 02:30:21 AM
Thanks for that Marty. I can compare my frame mounts with your measurements and take it from there.
Title: Re: BB 396 sits to low in 68 Camaro
Post by: Hatman on March 13, 2009, 12:48:03 PM
Let us know what you find out.
Title: Re: BB 396 sits to low in 68 Camaro
Post by: SS396 on March 14, 2009, 07:36:08 AM
Measured the height of my frame mounts and they are very close to the measurements that Marty posted. Looks like now that the problem may be with the gearbox crossmember and mount so I shall have to do some more homework.