Turbo 307 idea
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My brother's Buick 455, with a 2 barrel carb, gets around 24 to 28 MPG with mixed city/hwy driving...
Just keep a small cam, 900rpm stall converter, 2 barrel carb, tall rear-end (2.23:1 rear gear), and a good breathing system (intake/exhaust), and you'd be amazed at the mileage you get.
Just keep a small cam, 900rpm stall converter, 2 barrel carb, tall rear-end (2.23:1 rear gear), and a good breathing system (intake/exhaust), and you'd be amazed at the mileage you get.
85Supreme said:
Gas mileage is more a function of vehicle weight and driving habits than displacement. You're going to go through all the trouble of installing a turbo, then you're going to not put your foot in it? YEAAAAH, I believe that.
A 455 with a Qjet will deliver the mileage you want so long as you keep your foot out of the secondaries. The increased low-end torque will actually help around town by not requiring large throttle openings. The problem is when people do stupid builds with mismatched parts. They use an overly aggressive cam because somebody told them to and they use an 800 CFM double pumper because the magazine test said so, then they complain because they get 7 MPG. Use a reasonable cam matched to the axle ratio and driving style, use a spreadbore carb and a dual plane intake, and don't drive stupidly.
If you want to do ANYTHING to that 307... scrap it and take the $15 cash... if you cannot afford to build an Olds motor for it, drop in a small block chevy 350, (anyone who gets pissed by this can screw off. chevys are cheaper, easier, and more easy to find. besides, an Olds motor can replace a chevy just as easy as a chevy and olds.) Just by pulling a small block 305 out of a mid 80s chevy truck, you will notice a huge difference in power. the 307 is not a performance motor and it never will be. just ask Minion. it was built to be reliable, (and when takin care of, they were. my dad got 276k out of his 87 Cutlass Supreme and all he had to do to it was change the intake gasket once.) and they were built to have torque for pulling boats like the Cadillac Brougham/Fleetwood. The 307 is only a good motor when left STOCK and given the appropriate expectations. You would be much better off trying to build a Buick 3.8.
http://www.streetfire.net/video/71192mph_162017.htm
http://www.streetfire.net/video/73-letting-off-at-the-1000ft-mark_162025.htm
http://www.streetfire.net/video/71192mph_162017.htm
http://www.streetfire.net/video/73-letting-off-at-the-1000ft-mark_162025.htm
jeez,another one of these "soupe up a 307 thread". 
Anyway, yes it would be a cool, unique idea like everyone said,but olds motors arent designed for sustained high rpm use, limiting the turbo idea there. Second, all 307s have whats called windowed main webbing, meaning gm wanted to cut back on costs so they lightened the blocks right where the main caps go making them even weaker than the average 2 bolt main. Third, man its oldsmobile, not only would the turbo 307 idea be expensive, but just saying thats its olds makes it worse.
I have a olds 350 laying around if you want it for $150. I say build up a 350 olds for the cutlass, slap a set of edel heads on it,a qjet,upgrade the ignition to hei,throw a mild cam in it and you'll be much happier.
BTW anyone reading this saying in their heads "what about a supercharger on a 307" dream on. Streetable superchargers for 455 olds go for around $4k!
Anyway, yes it would be a cool, unique idea like everyone said,but olds motors arent designed for sustained high rpm use, limiting the turbo idea there. Second, all 307s have whats called windowed main webbing, meaning gm wanted to cut back on costs so they lightened the blocks right where the main caps go making them even weaker than the average 2 bolt main. Third, man its oldsmobile, not only would the turbo 307 idea be expensive, but just saying thats its olds makes it worse.
I have a olds 350 laying around if you want it for $150. I say build up a 350 olds for the cutlass, slap a set of edel heads on it,a qjet,upgrade the ignition to hei,throw a mild cam in it and you'll be much happier.
BTW anyone reading this saying in their heads "what about a supercharger on a 307" dream on. Streetable superchargers for 455 olds go for around $4k!
yea,i'm unfortunate enough to have a real high performance version of the 307! Bored .40 over,port matched heads,with a cracked and epoxied e-q-jet,DUI igniton and running threw a pair of tubular exhaust manifolds making 200 horsepower! 
Yes,the last owner of my cutlass did this to the 307,spent around $4k doing all that and for only 50 more horsepower?!
Worst part is, Its a good,clean engine thats never been abused and for $200 no one actaully wants it.It'd be a waste to take it to the scraper.
Yes,the last owner of my cutlass did this to the 307,spent around $4k doing all that and for only 50 more horsepower?!Worst part is, Its a good,clean engine thats never been abused and for $200 no one actaully wants it.It'd be a waste to take it to the scraper.
2fit661ca said:
joe_padavano said:
You're absolutely right I did find a couple 455's on CL for $500 or less, we weren't looking to build one though. My dad wanted a 403 and well we just got it. I think they're sought after because of the Trans Ams, but oh well it is what it is.
I'm a Pontiac guy and get the same flack for my 301's. I was around when the 301, 305, 307 were first produced and I can tell you they were not performance oriented at all. Mileage and emissions ruled and they filled the bill quite nicely. If anything, old 1950's style hot rod tricks work best. Like a little more cam, timing, a 4 barrel carb, rear gears, and dual exhausts work wonders until you bump up against the inherent design constraints of poor heads and weak reciprocating assemblies. Even a Turbo 301 is weak by 60's- 70's standards. A bigger motor just makes more power without even trying hard. I stuck with my 301 for mileage and I got it to perform pretty nicely with the above modifications, but it will never be a 400.
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