These frame stands are readily available in the aftermarket as reproductions.
Most LS engine adapters position the engine closer to the radiator, which is fine, because most of them do not run mechanical fans.
Short/Wide Mounts
Chevrolet used a different set of frame stands for the 307 than the 350 engine when installed in A-Body cars. The 307 frame stands are 1/2 inch taller than frame stands for the 350 engine. The width of the pad (where the two mounts come together) is also different. The 307 mounts are wider and measure 2⅝ inches on both the frame stand and the engine block mount. However, the block mount measures 1¾ inch tall and therefore is shorter than the 350 version.
These are the most commonly sold mounts at the parts store, so it pays to know the difference.
The type of mount you need depends on your vehicle and the accessory drive and oil pan you use. That being said, the best solution is to use the 350 version. These raise the engine a little higher than the 307, which provides better clearance for the oil pan and steering linkage. In most cases, you still need to raise the engine a little more to clear the steering linkage. About 1/2 inch usually works, depending on your oil pan and the angle of the engine/transmission. Most adapter plates require the 350 version.
Most A-Body cars have an interference issue with the inner tie-rod ends. The Mast oil pan for A-Body swaps has the best clearance, but you may need to raise the engine to get adequate clearance. The Hooker kit (shown) and similar kits have complementary parts that work as a complete system, and include mounts, pan, and headers.
Even with the right parts, some inner tie-rods are simply larger than others, which could result in light scrubbing, such as this on the bottom of the pan. This occurs at the extreme end of the turn radius.
With the mounts on the block, the engine can be lowered into the car for a test fit. It is a good idea to test fit your engine before finalizing the details.
Energy Suspension’s correct tall/narrow mounts provide adequate clearance using the Trans-dapt adapters and Mast oil pan. The inner tie-rods just barely touch at full lock.
For the 1969 Chevelle project featured in this book, the 350 mounts were used with a set of Energy Suspension 31117G motor mounts and a Mast oil pan. The driver-side inner tie-rod cleared, but the passenger’s side hit the pan. I raised the engine with an additional spacer block between the engine and the mount, which allowed everything to clear. The Energy Suspension mounts come with one spacer; I used two.
Hooker offers another LS swap solution for A-Body vehicles, particularly for non-Chevrolet brands that don’t have factory Chevy small-block frame stands. Instead of searching for Chevy small-block stands, you can use these pieces along with a fourth-generation Camaro LS motor mount to place the engine in the correct position. These are available in both “stock” position and in the 2-inch-forward position.
Using an aftermarket stand is an alternative to sourcing original Chevy small-block frame stands. Several versions are available with the most common being the Hooker (Holley Performance) mounts. These fabricated steel mounts bolt to the 1968–1972 frames in the factory-drilled forward Chevy small-block position. The stands are designed to fit Gen-IV F-Body (1998–2002 Camaro) block mounts. The two versions of this mount are stock engine position and forward position.
Under the hood of the 1971 Buick GS lies this 400-hp Buick 350. Although the engine is in great shape, it is time for something new. The latest generation of GM horsepower, the LT1, will do nicely.
Even though the Buick shares most of the chassis components with the rest of the A-Body platform, the frame stands are not compatible. Only Chevy small-block mounts work for LS swap adapters, so the Chevy small-block mounts need to be installed. The Buick mounts shown here are set back way too far and too wide.
Accessing the bolts is tricky; you need a combination of wrenches and sockets to get to each of the nuts and bolts through access holes in the frame. The bolts pass through from the backside of the frame member.
Position A, or the forward position, is designed to reduce floor-pan modifications for T56 6-speed transmissions and allows bolt-in installation of Turbo-Hydramatic 350, Turbo-Hydramatic 400, 2004R, 700R4, and 4L60/70 automatic transmissions. Position B, or stock engine position for a Gen I Chevy small-block, allows a TH350, TH400, or 2004R to mount to the engine using the stock crossmember without floor modifications. These mounts require extension floorpan mods with late-model transmissions and a custom transmission crossmember.
BRP offers a replacement mount that uses its proprietary Muscle Rods engine block mounts. This complete system includes a transmission crossmember and is designed to fit with Hedman Muscle Rod LS swap headers as well.
Chevelle small-block 350 stands replaced the Buick stands and, indeed, it makes a difference. The Chevy 307 stands are different from the big-block stands. For the install, I bolted them in place using the forward holes in the frame. All 1968–1972 A-Body frames are drilled for all types of frame stands. I also used new Grade-8 bolts.
Earlier A-Body cars use a variety of adapters. Chevrolet models are easy, as Chevy small-block adapters are the standard. If you are swapping into a BOP A-Body car, you need to swap out the original mount for the Chevy small-block-type mounts. Although the non-Chevrolet mounts look as if they are the same or similar, they have different dimensions that are not compatible for completing a swap.
Another issue is that BOP frame stands are often in a different position than Chevrolet versions, similar to the later 1968–1972 frames. The most common solution is to use the 1964–1967 Chevelle 350 mounts for these early A-Body swaps.
Unlike the 1968–1972 models, the 1967-and-earlier frames use a single bolt pattern for all GM makes, three bolts in a triangular pattern. The frame stands themselves are different. This means that you must install Chevy small-block engine stands into the frame. Some swappers weld the engine stands to the frame, which demands a serious commitment to the placement of the engine. You must be 100-percent sure that the location is correct.
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