94-96 Roadmaster Engine

[Guest]

Hello All. I have a 92 Roadmaster Limited whose engine just failed. I need to put a new engine in this vehicle. I know that the 94+ Roadmasters came with a much higher performance engine (LT1) than the 92,93 5.7L. Does anyone know what is involved in installing this newer engine? Better yet, would anyone know of a Southern California contact for getting this done? Thanks!

[NTX5467]

The earlier engines were the normal, 210 horsepower Throttle Body Injected 5.7L V-8, if I recall correctly. Not a bad running engine at all AND not subject to some of the expensive problem areas of the LT1 engines as they age.

If you do find a useable LT1 engine, you will most probably need the complete engine wiring harness AND computer. The later engines are most probably OBD II compliant and that's a whole bunch of other stuff too. In OBD I, there was basically one oxygen sensor in the exhaust system to monitor and adjust the fuel mixture. With OBD II, you get an engine monitoring sensor AND a catalyst monitoring sensor. Quite a bit of difference in the two systems!

PLUS, if you put a "newer engine in an earlier model chassis", then your vehicle will most probably need to also meet the newer total engine's exhaust/evaporative emissions standards, regardless of the year (unless there is an exemption that your vehicle is not old enough to be able to use).

Many of the LT1 Roadmasters came with factory dual exhaust, which did help their performance some, even with the smallish tube diameter of the exhaust pipes.

One of the expensive areas to repair of the LT1 engine is the OptiSpark distributor for the ignition system. The orientation is a neat one, but when the seals get oil past them, it can be nearly $500.00 to replace it. The spark plug wires only come as a "harness" and are quite expensive to replace too. The water pump is run by a splined shaft that attaches to the camshaft, which is kind of neat too. End result, a good many maintenance and wear items that are unique to that motor setup and not the cheapest thing in the world to repair/replace.

In short, you might be better off keeping or repairing the 5.7L Chevrolet engine you currently have in the car. As for improving the performance of the stock engine, Edlebrock makes an intake that is basically their aftermarket 4bbl intake but with a mounting pad to accept the throttle body fuel injection unit. They might even have a larger throttle body unit too.

Then you can address the exhaust system. Doing a dual exhaust system similar to the LT1 Roadmaster setup might help, especially with a low restriction and quiet muffler setup. On the factory dual exhaust LT1 cars, for left hand pipe clearance, they used a really trick aluminum spacer to mount a PF52 oil filter instead of the PF25 or PF35 filter that was normally used. The plug also moved the filter from the center of the plug to one side of it, moving the filter closer in toward the engine block in the process. Something a street rod person with tight exhaust clearances on their street rod could really appreciate!

In other words, with a few add-on items, you could approximate the extra power output of the newer model LT1 engine without all of the hassles involved in swapping one into your vehicle. Sure, it would bolt in, but it's all of those side issues that would be the pains (time and money) to deal with.

If you do decide to swap in an LT1, then you will need BOTH cars side by side to swap EVERYTHING over from the donor vehicle to your vehicle. When done, they you can let the donor vehicle head to the salvage yard.

Just some thoughts,

NTX5467