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Old 02-24-2003, 04:20 PM   #1
Brett

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Default What are some good Olds 307 mods?

I have an '85 Delta 88, with the 307. I've only had it for two months now, and from my research, it seems as though this engine is considered worthless and unresponsive to modifications.

What do you all think?

Is there anything worth doing to this engine? I would like to give it a bit more pep, but I would rather not spend the money if it is a lost cause.

Also, my carburetor keeps flooding in this cold, and I have to manually jack it open quite often. Any suggestions?

Thanks a lot.




Brett
 
Old 02-24-2003, 05:01 PM   #2
Ryan Michelotti
 
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It's a lost cause, don't spend the money.

Drop-kick the 307, and install ANYTHING bigger. 330-350-403-425-455

As long as you stay with Olds, they all bolt right in.

Ryan
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Old 02-24-2003, 08:07 PM   #3
Rob

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307's come with either 5A or 7A coded heads. The one you have should have 7A heads. 5A's are more preferred because they have larger ports, while the 7A's have tiny ports. There's really not a whole lot you can do with the 7A's. They don't breathe very well because of the ports and you can't get an aftermarket intake. You're stuck with the factory one. It will also have a roller cam. Getting an aftermarket cam means=big money. Bottom line is the 307 is a good reliable engine for everyday use but far from the best choice for mods and buildups.

Not sure on the flooding problem without more info. It sounds like either the float or the needle/seat inside the carb is bad. It might have something to do with the computer but I doubt it.
 
Old 02-24-2003, 08:22 PM   #4
Brett

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Thanks for the info guys. That is pretty much the same exact story I have heard elsewhere. I think I would rather keep the car reliable and fuel efficient, as it is a money saver car in the first place. I was just wondering if there were some quick little things I could do to gain 10-20 hp for very cheap.

As for the carb, the choke gets cold and won't open up, so then it floods, so I have to manually do it. It's not a big deal, I just thought others had probably experienced the same thing, and wondered if they knew any tricks to help it out a bit.



Brett
 
Old 02-24-2003, 08:29 PM   #5
Rob

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You may have a bad choke unit. On the side of the carb is a black looking piece with a wire running to it. That will be the choke spring unit. It is electronically controlled. You could try replacing it. It should run you inside $20, although you have to drill out the rivots that hold it in and either rivot it back in or try some tiny nuts and bolts.

By the way, it never hurts to upgrade your exhaust to help performance.
 
Old 02-24-2003, 08:50 PM   #6
Rob

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Quote:
Originally posted by Kevin
Oldsmobile never had electric chokes, so there is no wire.
My mistake. Olds always had that hot air tube running through the crossover.
 
Old 02-25-2003, 03:57 AM   #7
jesusworks

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http://performanceolds307.tripod.com/

thats chris's site he has basic hit a brick wall with the 307 proformance wise. you can deffenetly make that 307 holds its own. a5 heads, vin 9 cam, better reargears, better exhaust, get more "colder" air coming down the intake. check out christopher in tampas site you'll see!
 
Old 02-25-2003, 03:59 AM   #8
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Kevins right, your choke is your problem, There is a vacume diaphram on the front passinger side of the carb that has a rod that connects to the secondary air valve (four barrel for non carb speaking people) First make sure that this diaphram is still good and not leaking, if you look at that diaphram you will notice that there is a phillips screw located on the diaphram itself, that screw is what adjusts the pull off of your choke, what you want to do is adjust this so that when the diaphram receives vacume (anytime engine is running) it will crack open the choke flap further then it already does so that you will have less choke once the engine starts, this will fix your problem.
as for cheap mods well there ant much that can be done to 7A heads, 307s with the 5A heads have better performance and can be modified much easier with more success but it doesnt hurt to get the best out of what you have as long as you dont dump too much money into it, your 307 will respond best to drivetrain improvments and the best part is these changes will be there for your next engine, check out my site for some cheap mods that can improve your 307s performance if you like http://performanceolds307.tripod.com
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Last edited by Christopher In Tampa : 02-25-2003 at 04:03 AM.
 
Old 02-25-2003, 07:22 AM   #9
shortymac83

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5A heads, and an Edelbrock intake should get you some easy HP. The intake is probably the best bet.
 
Old 02-25-2003, 11:52 AM   #10
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Yeah them 5A heads and intake will drop your 0-60 by 2 seconds at worst but maybe more then 2 seconds if your lucky, Usaly a completely bone stock 307 Y with gearing in the 2.** runs 0-60 anywere from low 11 seconds to 13 seconds, 5A heads will drop you a good 2 seconds just like that and from there you can gain lower 0-60 times with better drivetrain and simple stuff like electronic cooling fans, exhuast and induction
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Old 02-25-2003, 02:40 PM   #11
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Check the head # at the left front corner of the driver's side head-if yours is a very early 85, then you may already have 5A heads.

Probably the best thing you can do for relatively cheap is upgrade to what everyone calls "VIN 9' specs. The Hursts and 442 models got a version of the 307 that was up 30 HP over the stock 307.The engine code in the VIN # was 9 instead of Y, hence the nickname.


The VIN 9 307 had a different balancer, cam and carburetor. The balancer and cam are still available from GM to the best of my knowledge, and the main difference in the carb was that the secondary air doors opened up fully(also to the best of my knowledge).

By this time most 307's could use a new timing chain and water pump, so changing the cam wouldn't be much more trouble.

If you have a 7A 307, then you can really only change the above mentioned items, since the ports on 7A heads are about half the size of 5A 307 heads. The 5A heads aren't interchangeble with(replaced with) better 350 heads because the bore on the 307 is too small.However, things like intakes and headers will bolt right on to the 5A.

Seeing how a 5A 442 was rated at 180hp, it should be possible to get a solid 200hp out of a 307 by doing some tricks and tuning.

Most Delta's should have had a 4 spd automatic by '85. Your car would LOVE gears, and with OD, it's perfectly livable. I think 3.73's are a good choice, and it will seem like your car gained 40 hp(my Mustang dropped 1 full second in the quarter just by swapping from 2.73's to 3.73's).

Good Luck!
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Old 02-25-2003, 02:53 PM   #12
Brett

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Thanks again. My car does have the 4 speed, but it has the Y VIN #.

How much would it be to swap the gears?



Brett
 
Old 02-25-2003, 04:37 PM   #13
GBH

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Actually, I would half-expect his 85 to have 6A heads. My grandma's 85 LeSabre has 'em. Stainless manifolds, too.

Swapping gears is a PITA for a newbie; it may be better to have it done. Since you have the OD, anywhere from 3.23-3.73s would be perfect. S10 pickups are good boneyard candidates for deeper gears for the 7.5" axle. If you can find a deeper gearset in an axle from the same body style, an axle swap is easy money. Make sure before you pull it that it has the same bolt pattern as your current rear. A brake line, two shocks, two e-brake cables, four bolts, then you're done. Have a buddy to help you wrestle it, though I've changed mine myself more than once. They are heavy.

-Glen
 
Old 02-25-2003, 05:13 PM   #14
GBH

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Whatever 307 you have will respond favorably to tweaking. Tune it up, tweak the secondaries, bump the initial timing up a couple degrees, and put some good dual exhaust on it. If you're restricted by emissions checks, at least put on a hi-flow cat and dual cat-back exhaust. You don't need a kit, just a good muffler shop. Walker exhaust made all GMs OEM stuff back then, so new pipes are cheap and readily available. Otherwise the shop can just bend 'em up. If you can at least keep the stock outside air duct in place, the cooler air will help reduce the engines octane sensitivity, making it less likely to ping, even with more timing advance.
Then swap in a set of 3.42/3.73 gears and put a shift kit in your 200-4R. You'll think it's a beast.

Try these links:
http://www.ptsnctb.com/mcartfree/pro...p?intProdID=88
^Bruce Toelle is the official man for these trannys
http://www.thirdgen.org/newdesign/tech/
http://www.thirdgen.org/newdesign/tech/rods.shtml
http://www.thirdgen.org/newdesign/tech/quadrajet.shtml
http://www.thirdgen.org/newdesign/te...lsnorkel.shtml
 
Old 02-26-2003, 06:59 AM   #15
shortymac83

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A Bit OT, but where should I look for a set of 3.73's?
 
Old 02-26-2003, 12:35 PM   #16
ez112

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Give me like four months and I'll tell you how they all are...
 
 


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