Bbc sbc mounting points

[blake sheets]

I have a bare 454 bbc bolted onto the TH400 i will be using in my car and i have it mocked up so i can fabricate my crossmember for the trans and weld on my motor mounts to the frame. i will be running a sbc 400 in this car and i want to know if using the bbc for mock up with change the location of my trans crossmember or my motor mounts. as far as i know bbc and sbc mounts are all pretty much standard and are the same, but i want to clarify before i start this process.

 

[dr78442]

BBC and SBC have the same mounting location. The frame is predrilled so the mounts can be bolted in

 

[565bbchevy]

Agreed, the mounts are the same even though the BBC is longer the extra length go towards the radiator.
And as stated there are holes to bolt them in but the factory Gbody frame mount contains the rubber that helps isolate engine vibrations and this part can break so you would not want to weld it the frame but if you feel the need to weld mounts to the frame then go with a solid frame mount that accepts the upper clamshell engine mount or with something like Mororso solid mounts that give extra clearance for headers.
https://www.summitracing.com/parts/upi-0051/overview/year/1982/make/chevrolet/model/monte-carlo

 

[Texas82GP]

Here are a couple of pics that show where to bolt the mounts for SBC/BBC. One corner hangs over the crossmember and only three bolts are used. Totally normal.

 

[lilbowtie]

I would advise to bolt the mounts in - I found there are two different heights for the frame mounts and not that bbc & sbc can't share the same mount but I found it is critical for header fitment between the two.

 

[blake sheets]

I bought the umi solid motor mounts for the frame and for the block and i couldnt find 4 holes that match up... and the solids have a different bolt pattern than factory mounts. this is also going into a 84 grand prix, idk if they didnt drill holes for the sbc or not but its kind of puzzling... when i get home from work ill check and see if i can get 3 bolts in them.

 

[54BBChevy]

I would advise to bolt the mounts in - I found there are two different heights for the frame mounts and not that bbc & sbc can't share the same mount but I found it is critical for header fitment between the two.

[REPLY=Newbie 54BBChevy, post:] How do you identify the taller frame mounts at the parts store (part #, or vehicle & year)? I am trying to put a 454 into a 1980 G Body chassis. Thank you for your help.

 

[L67ss]

No need to fab up a th400 cross member. You just need a factory 2004r cross member. Direct bolt in

 

[L67ss]

There's where ya wanna locate the mounts

 

[pontiacgp]

Here are a couple of pics that show where to bolt the mounts for SBC/BBC. One corner hangs over the crossmember and only three bolts are used. Totally normal.
View attachment 57603
View attachment 57604

I used serrated flanged grade 8 bolts and nuts for my engine mounts. With the serrated flanges once the flange touches the metal you don't have to hold the nut to torque them making the install easy. I also used some locktite on them. This info from the vaults of the proud lazy man...😎