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Your friend's Mustang project sounds interesting - as 347 strokers usually are. Remind your friend Mike that the 4-cylinder Mustang had smaller brakes and a weaker differential than the factory V-8 -equipped Mustangs - so those components, among others, must be upgraded, along with the suspension, in order to safely handle the extra power of the 347. What is Mike's choice of transmission for the '89? I only ask because the stock trans very likely has to be replaced, anyway.
I can't speak for anyone else here but I respect Oldsmobiles. Back in the early 50's, I understand that
they were considered 'musclecars' by the 'hot rodders' of the day. Quick cars...even with the weight and automatic transmissions most Oldsmobiles came with. The Olds 303 and 347 cubic inch OHV V-8's (manufactured between 1949 and 1963) were also very valued by 'GM guys' looking for a V-8 to put into their gasping, six-cylinder Chevrolet grocery-getters in order to challenge the many Ford flathead V-8's (then in Model A's and later Ford's) on the street racing scene. Yes, I've seen
'American Graffiti' too).
The mid-60's-era Olds
442 was a great idea (Oldsmobile's version of the GTO) but like it's better-known 'cousin', the Pontiac GTO, it quickly got 'fat' and was eventually killed off (in '74) by increasingly strict federal emissions requirements on the fabeled 400 cubic-inch and later, the 455 c.i. V-8's that powered the later '442'.
I am not as impressed with the late-model ('80's and '90's) Oldsmobiles for a variety of reasons. As a model that was not especially interesting in it's later years and that has been discontinued by the manufacturer, it is interesting to see anyone use the Oldsmobile as a project car. It must be a challenge. Good luck with it, all the same.