I have been reading BBC install threads and was wondering if anyone has tried moving the engine and transmission a little to the right away from the steering box. The reason I ask is when Chevrolet put a BBC in the first generation Camaro the left exhaust manifold interfered with the steering box just like it does in a Tri-five. To solve this problem the engineers used asymmetric frame brackets and an offset transmission cross member to move the engine (and transmission) a good half inch to the right of the center line of the car.
I have read many posts about moving the engine forward for clearance but haven't seen anything about moving the engine and transmission to the right. I figure if it was good enough for the 396 Camaro it's good enough for a Tri-five Chevy. A little extra space between the steering box and the hot exhaust is worth a slightly off center engine.
In order to gain engine compartment clearance, big block (BB) engines were offset 1/2 inch to the right (towards the passenger side) by means of asymmetric brackets. 1967-68 BB frame mount brackets are 2-1/2 inches wide (but not the same as SB) and use the same engine mounts as 67-68 302ci and 350ci. For 69, BB frame mount brackets were redesigned to use the new thicker, narrower, engine mount also used by 302ci and 350ci. BBC bracket pairs are easily spotted because the left bracket is noticeably taller than the right in order to achieve the engine offset.
offsetting the motor is not a problem as long as the trans mount is offset by the same amount so crank is parallel to pinion shaft in the diff.
i have done it up to three quarters of an inch in cases due to starter motor/ steering rack issues with right hand drive cars here in australia.
I have been reading BBC install threads and was wondering if anyone has tried moving the engine and transmission a little to the right away from the steering box. The reason I ask is when Chevrolet put a BBC in the first generation Camaro the left exhaust manifold interfered with the steering box just like it does in a Tri-five. To solve this problem the engineers used asymmetric frame brackets and an offset transmission cross member to move the engine (and transmission) a good half inch to the right of the center line of the car.
I have read many posts about moving the engine forward for clearance but haven't seen anything about moving the engine and transmission to the right. I figure if it was good enough for the 396 Camaro it's good enough for a Tri-five Chevy. A little extra space between the steering box and the hot exhaust is worth a slightly off center engine.
No issue with the driveline as stated above.
Check the pass side header clearance though, mine is fairly tight on that side also. No interference on the steering box with a stock box, no interferences either side.
Pushing the engine sideways, you also need to consider the K Frame positioning, the engine height may also be affected, the radiator set up with the fan positioned to one side may affect cooling, and you`ll need to consider getting the pinion angle/transmission tail shaft all lined up.
Pushing the engine sideways, you also need to consider the K Frame positioning, the engine height may also be affected, the radiator set up with the fan positioned to one side may affect cooling, and you`ll need to consider getting the pinion angle/transmission tail shaft all lined up.
the only thing that happens when you shift the engine sideways some is the pass header gets real tight. there is no affect to the cooling system and no affect on the frame.
Doesn't Earl Williams have a nice mount that allows for side to side?
Those Earle Williams motor mounts look really good. The new style mounts have the option of mounting the engine in the standard position or ¾ inch forward and also has slots to shift the engine side to side.
Another thing to consider on a big block installation is crossmember sag. Crossmember sag is common in Tri-five Chevy's. Not only does it cause wheel alignment issues but it also causes the top of steering box to tilt inward toward the center of the car. This is exactly what you don't want when installing a big block. This inward tilt is worse at the top because the frame where the box bolts up is no longer plumb. I believe frame sag is why some cars have more of a problem with steering box clearance than others.
The weight of the car is constantly trying to push the frame rails together. Think of the control arms as levers and the narrow stock engine mounts as the fulcrum. The strength of the front crossmember is all there is keeping everything in position. When you hit a pothole these forces on the crossmember are amplified. The weight of the engine is pushing down and the upper control arms are pushing in. Over the years the front crossmember bends and the top of the frame rails move closer together. On my car my frame rails had moved 3/8 of an inch closer together (3/16" per side). I had a body shop pull my frame back into specs. Actually they pulled it an additional 1/4 inch wider which is 1/8 inch per side.
I wonder if side motor mounts will brace the frame rails and help prevent the crossmember from bending. What do you think?
I think they might help because the forces due to the engine weight are moved outboard.
But, I'm a bigger believer in collision damage causing frame sag as opposed to wear and tear. Potholes and curbs are in the collision damage category too.
Moving engine away from steering box
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