Thread: Engine Upgrade
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Old 10-05-2012, 01:32 PM
Gen1dak Gen1dak is offline
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Vehicle: 1990 RamCharger
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Engine: 1988-1991 318ci (5.2L) LA V8 140hp
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The 42, aka, the A500, is an outgrowth of the 904-series Torqueflite. While the 904 was originally developed as the 3-speed automatic for 6-cylinder engines, it became standard equipment in Chrysler B-bodies (Charger, Satellite, Coronet) behind the 318 V-8 in 1969. Those are 2 ton cars. The 900-series Torqueflite was further developed into V8 car and truck models (998 and 999). The fact of the matter is that the 900-series is more than capable of handling anything a street smallblock V8 can dish out. Specially prepped 904 guts are even used behind Super Stock 426 Hemi Darts. These cars run low-10's in the quarter all day. The 900-series was used behind 318's and 360's in 2WD Ramchargers all day long. V8 torque, 5,000lb trucks. The problem with the 42's, as well as the 46's, is the common overdrive unit they share. It was originally developed to handle 400 ft-lbs input torque. Any of you guys kickin' out 400 lbs torque with your smallblock? Not many. The OD was an add-on, and coolant is critical. It comes down to this, keep the OD cool (and it tends to run hot), and the
transmission will live. My '89 Shelby Dak was the first with a factory V8 (318-only 270 lbs torque) and had the A500 - later redesignated as the 42RH, then 42RE. Six times it burned up and I never even towed anything. Just runnin' up and down I-10. Every time it was the OD. The original design of the "front three" that came from the 904 was always fine. The egghead-designed OD was what failed. Failures were much higher in the A500 because of the smaller coolant passages....something that was fixed in later models by Mopar, but leave it to the aftermarket to solve the problems and it did. Get an aftermarket valvebody kit and it'll be great. The valvebody kits make a huge improvement in lube and overall performance.
Not designed for? The 42 is more than strong enough. Wanna haul a horse trailer, get a 46. In HD everyday situations, the bigger clutches will take the abuse even longer, but it's the OD that's gonna be the weak link, and it's the same unit on the 42 and the 46.

Last edited by Gen1dak; 10-06-2012 at 03:44 AM.
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