CUTLASS casting no. finally

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MrSony

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Nov 15, 2014
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Much like a 305 chevy, the 307 was just there to make the car "go", and it did. Eventually.
Swap in an early 70s 350, or the late 70s 403 as said above, everything will swap over. You could even build a tame 305 or 403, and put all the computer stuffs back on. Might have to jet up the carb to compensate, not too familiar with the computer stuff, but it's been done. iirc some guy did it with a 455. But, all you'd really need for the swap would literally just be the engine, non computer qjet and distributor. Everything else bolts up.
 

MrSony

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Nov 15, 2014
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Oct 14, 2008
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All that 75 motor needs to perform is flat top pistons, would give around 9 to 1 compression, an upgraded cam, 2" or 2.07" intake valve with the bowls opened, the bowls opened on the exhaust side, headers and dual exhaust, there is a lip under the exhaust valves. The computer carb on the 85 and later were designed for a 8 to 1 307 with 60 degrees of part throttle timing. It would run OK on the stock 75 350 but forget the mods mentioned above. Get the Street Demon carb and a vacuum advance distributor if you want better performance. If the stock distributor and 800 cfm carb come with, they can be used. The 75 carb has that weird extra power piston but a carb builder like Everyday Performance can modify and tune to any upgrades over stock. The mid 70's Qjet's are very good but very lean from the factory.
 

DRIVEN

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Apr 25, 2009
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so the 86 307 is not a high speed motor but it has good torque on the bottom end just not a lot of hp? so should i stick with it for daily driving or get a 350 out of a 70's and rebuild it ?
All depends on what your end goal is with the car. For a cruiser, the 307 is great. You'll probably never be satisfied with the performance though as they were intended to get good gas mileage and last a long time while meeting emissions requirements. Keep in mind, these were used in Cadillacs for years because they were "clean" enough and had enough torque to fill that need. I've got no gripe against the 307, but it was never intended to be a performance engine.
If going fast is your primary focus then all of the 350/403/455 swap advice is valid. Just remember that Olds was always good at torque which translates to transmission and rearend upgrades.
 
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fleming442

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Dec 26, 2013
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All depends on what your end goal is with the car. For a cruiser, the 307 is great. You'll probably never be satisfied with the performance though as they were intended to get good gas mileage and last a long time while meeting emissions requirements. Keep in mind, these were used in Cadillacs for years because they were "clean" enough and had enough torque to fill that need. I've got no gripe against the 307, but it was never intended to be a performance engine.
If going fast is your primary focus then all of the 350/403/455 swap advice is valid. Just remember that Olds was always good at torque which translates to transmission and rearend upgrades.
....and Torque Face!o_O
:D
 
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oldolds

Greasemonkey
May 17, 2017
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it should be easy to put a 350 engine in because there is no computer it is the last year (1980) without a computer. the previous engine was a 307 but someone put a 307 out of an 85 apparently but messed up on the vacuum and electrical it runs but just because I mickey mouse the electrical and capped off the vacuum lines just to get it out of the guy's yard. I got it home and looked a little more and found out there are no fusible links off of the starter so I disconnected the battery and now I am trying to fix the electrical like the headlight switch was melted and the part that screws into as well. those plastic parts are hard to find in the wrecking yards so it is a little at a time.I have a shop manual which helps but there are a few pages in the back missing. so it is a little at a time. the motor that is in there only has a few thousand miles on it, and it was free so it will come alive soon, then on to the interior, new headliner and carpet needed, and fix the electric seats, all on a budget as I can afford it. is this an abody or a gbody? it is a 1980 olds cutlass Calais with t tops and electric seats.
 
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