al5570
04-14-2007, 07:38:43 PM
To marks71BB
someone told me to ask you about motor mounts.....i am getting close to putting my 454 in and the motor mount issue has come up. its a pretty mild build, nothing too crazy. so whats going to work best for me would you think, rubber, solid, or poly. ive read up on what i can, but cnt really tell if one is better than the other. thanks
andy
What year? I guess I coulds looked in your profile but I allready hit the reply button.
There was a signifigant change in design circa 73. Prior years had the saddle on tower similar to the first gen. They had problems with the torque (sb and Bb) and tearing the driver side rubber. GM hadnt counted on the powerful lift on that side of the motror. as for BB vs SB mounts go they are interchangeable providing you have a correct pair. There were two diffrent sets one set had the towers about 5/8" lower. My suspisions were they were used both on the bb to lower the engine for hood clearance AND they were used in the Z/28 for a lower center of gravity.
I was talking to a fellow enthusiast just yesterday (David Pozzi very knowledgeable) and he indicated the BB mm shifted the engine to the passenger side. that could explain why I had to add washers between the saddle mount and the block to get clearance for my fat headers.
Anyway as for the tearing of the motor mounts the aftermarket came up (and oem replacement) with tabs on the upper mount to restrict upper motion of the engine. They worked for either side so they were the standard replacement for the left or right side allthough only realy needed on the driver side (except maybee in a four speed who down shifts real hard).
To solve this problem GM switched to the clamshell style motor mount in the middle of the 73 model year where as the isolation is done on the frame side instead of the engine side. Those are prety straight forward. I prefer the towers but it tepends on the year if it will have the holes in the frame for them.
Bottom line is the BB and SB share a common dimension center to center on the motor mount through bolts and for the most part (other than a slight position shift (which can affect the fan/shroud clearances and headers)) they are largely interchangeable.
Make this a post for me if ya want I love being quoted;)
Cheers,
Mark
someone told me to ask you about motor mounts.....i am getting close to putting my 454 in and the motor mount issue has come up. its a pretty mild build, nothing too crazy. so whats going to work best for me would you think, rubber, solid, or poly. ive read up on what i can, but cnt really tell if one is better than the other. thanks
andy
What year? I guess I coulds looked in your profile but I allready hit the reply button.
There was a signifigant change in design circa 73. Prior years had the saddle on tower similar to the first gen. They had problems with the torque (sb and Bb) and tearing the driver side rubber. GM hadnt counted on the powerful lift on that side of the motror. as for BB vs SB mounts go they are interchangeable providing you have a correct pair. There were two diffrent sets one set had the towers about 5/8" lower. My suspisions were they were used both on the bb to lower the engine for hood clearance AND they were used in the Z/28 for a lower center of gravity.
I was talking to a fellow enthusiast just yesterday (David Pozzi very knowledgeable) and he indicated the BB mm shifted the engine to the passenger side. that could explain why I had to add washers between the saddle mount and the block to get clearance for my fat headers.
Anyway as for the tearing of the motor mounts the aftermarket came up (and oem replacement) with tabs on the upper mount to restrict upper motion of the engine. They worked for either side so they were the standard replacement for the left or right side allthough only realy needed on the driver side (except maybee in a four speed who down shifts real hard).
To solve this problem GM switched to the clamshell style motor mount in the middle of the 73 model year where as the isolation is done on the frame side instead of the engine side. Those are prety straight forward. I prefer the towers but it tepends on the year if it will have the holes in the frame for them.
Bottom line is the BB and SB share a common dimension center to center on the motor mount through bolts and for the most part (other than a slight position shift (which can affect the fan/shroud clearances and headers)) they are largely interchangeable.
Make this a post for me if ya want I love being quoted;)
Cheers,
Mark