malibujames said:
i was reading in a different forum about adapting an ls engine to a th 350 but my question is does anyone make anything to adapt an old small block to a 4l60e or any electronic trans or would it be easier to throw a 700r4 in it for overdrive. and whats the difference it gear setups it is for a street car so not much hp or tq is there.
A 4L60E as well as the 4L80E will readily bolt up to a first generation small block engine. No adapters are required. As was previously stated by another member, an aftermarket electronic controller will be required for the 4L60E to function properly in a retro-fit application. The only advantage of retro-fitting a 4L60E is the increased tunability you have with the electronically controlled transmission and aftermarket controller. You can fine tune line pressure, shift firmness, shift speed, and switch between automatic and full manual modes with a properly designed controller. However, the cost associated with this conversion is typically not justified for most street car owners that are simply looking for the advantage of an overdrive transmission.
All gear ratios are identical between the 700R-4, 4L60, 4L60E, 4L65E, and 4L70E. However, many 4L65E and all 4L70E transmissions feature stronger 5-pinion planetary gear sets. These gear sets will retro-fit into an earlier 700R-4, 4L60, or 4L60E transmission for those people that are looking to help maximize the durability of an earlier transmission in a higher horsepower and/or higher torque application. However, this gear set swap would be entirely unnecessary in a basic low-to-medium horsepower street car. The normal 4-pinion gear sets are more than sufficient for basic cruising and moderate performance use. The 4L60 family of transmissions does offer a 3.06 first gear ratio which can be advantageous for a person that is wanting to increase low gear torque multiplication and performance without having to change rear axle ratios. Of course, this increase in first gear ratio results in a larger RPM drop on the 1-2 shift as compared to the remaining gear changes. This isn't really problem in a street car, but does provide for a different feel in terms of drivability as acceleration is not as linear upon each gear change as compared to other transmissions that have a more balanced spread in gear ratios such as the 200-4R, which features a 2.74 first gear ratio (still an improvement over any 3-speed auto trans first gear ratio).