All V8 cranks use the same bolt pattern (except the late hemi which has an eight bolt flange) and flex plates will interchange, but some converters have different bolt patterns, so you have to use the flex plate that fits the bolt pattern on the converter you use. I used a small block flex plate to drive the ten inch converter in my big-block bracket racer, back in the early eighties. The only "unbalanced" flex plates available for externally balanced cast cranks are typically made by the aftermarket (such as B&M, and others) for custom installations, from the factory, all the balancing is done with a weight on the converter itself. It's almost impossible to purchase a rebuilt converter these days without the weight on it, when I need one for a forged crank I just knock the weight off and install it, works just fine. The part-throttle kick down feature brought out in the seventies didn't require a different converter, most likely any changes that were made to the converter, were to increase the stall speed to help offset the lower engine performance brought about by the emissions-related "detuning" the factory was being forced to do. Mike At 09:27 AM 4/8/2004 -0700, Robert Merritt wrote: >Gloria, >The swap you are asking about won't work because the bolt pattern on the >small-block series engines, 273, 318, 340, and 360 is different from the >big-blocks, 361, 383, 426, 440. Therefore, even though both series engines >use the 727 transmission, it takes a different transmission case to fit >the different engines. Otherwise, pickup and car transmissions from >similar years and engine sizes will bolt in interchangably >Another thing to watch for, even if both the years mentioned were to fit >the same engine, the engines built in 1971 and earlier had a forged steel >crankshaft and in 1972 or 1973 they were phased out and started using a >cast crank, which required external balance weight added to both the >harmonic balancer on the front of the crankshaft and the transmission >torque converter. >Also, starting in the later 1970s, the transmissions had part-throttle >downshift, which required a different converter. >Best to find the correct transmission. >Good Luck, Okie Bob ------------------------ Yahoo! Groups Sponsor ---------------------~--> Yahoo! Autos. Everything you need to know about buying or selling a car. FREE Quotes, 360° Tours, Research, Blue Book, Compare Vehicles, Buy Used http://us.click.yahoo.com/kEZsdA/bwnGAA/YiGOAA/8LmulB/TM ---------------------------------------------------------------------~-> To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/