Pro's Con's of vehicle emission system

[85 Cutlass Brougham]

Well, they used a larger catalytic converter on the HO models than the regular ones, at least on the MC and Turbo Regal models they did. The normal V8's had a 2.25 in cat on them, but the HO models used a oval inlet that basically is a slightly squeezed down 3 in pipe and it flows more. It is the same cat used on Corvettes and high performance F bodies (L-69, some TPI) of the period. Some aftermarket exhausts for our cars suck though as the Y pipe coming off the HO cat is quite restrictive and necks down to a 2.5 in pipe. The Dynomax exhaust specifically comes to mind in this regard. The better ones basically have 2 pipes that come off the cat flange and flow quite better. I have the unfortunate Dynomax exhaust on mine and plan to either change out this section of piping, or do away with it all together and get true duals as I feel it is a cork holding my engine back as it sits.

 

[devious]

start with a tuneup.

Next time you come into a thread with a serious question please be prepared to have a serious answer I am not some car n00b just a beginner trying to gather infromation and further my knowledge

As for the rest of the post's I apreciate all the input. Im new to the whole olds/buick thing my knowledge really goes no further then chevy. I kinda figured it would be more trouble and do more harm then good thats why i figured Id ask. I am planning on doing a motor build but if you think a re-built 307 couldnt offer much in the performance category then I might have to upgrade and i really don't want to put a chevy motor in a buick. Really as far as my plans with this car goes is to build it to just cruise I don't want anything real high performance as I have another car for that, I just want to build this one to be able to get into it start it and just drive and have decent gas mileage but on the other side I also want it to be able to pass someone on the highway and not act like it's going to die when I hit 55. Everything is stock on it the only thing that has been changed is the radio so basically im starting from step one, I think the first major thing I will do since it is running is start with the exhaust any tips for that? what about getting rid of the cat?

and another question if i do re-build an olds motor what parts are diff from a chevy one? (probably dumb question)

Thanks for everything

 

[joe_padavano]

and another question if i do re-build an olds motor what parts are diff from a chevy one? (probably dumb question)

Thanks for everything

All of them. The only thing the Olds and Chevy motors have in common is the distributor cap. The folks who said to change the gearing were right on target. Many of these mid-80s cars came with 2.14 or 2.56 gears. A 3.42 or 3.73 will really wake this car up.

If you do plan to build an Olds motor, start with a 350 or 403. Either is a direct bolt in for the 307.

 

[dan2286]

Here is a good site that has a lot of info about doing the swap with an Olds. You can even keep the computer if you keep the engine mild enough.

http://www.robertpowersmotorsports.com/Technical_Info.html

 

[shotgun]

No Olds expert, but there are factory tube type shorty exhaust manifolds out there.

We swapped a 307 into a S10 using exhaust manifolds from a Olds powered Cadillac. I don't recall the year but the manifolds were tubular vs cast.

Also on exhaust, I would suggest a nice mandrel bent 2.5" single if you plan on staying close to stock. It will support 250hp. Add a nice aftermarket crossflow muffler (dynomax) in the stock location and you have a well matched exhaust.

If you plan on stepping up, a single 3" will support 300 hp ( think SLP Fbody), again with a crossflow (maybe even for a fbody) muffler.

Going "single" weighs less and gets rid of crossmember fitment issues also.

 

[joe_padavano]

No Olds expert, but there are factory tube type shorty exhaust manifolds out there.

The only factory "tube type" exhaust manifolds for an Olds are the welded tubular log manifolds used on the 86-90 307 motors. They suck from a flow standpoint. The ports are significantly smaller than those on all other Olds motors.

 

[dan2286]

No Olds expert, but there are factory tube type shorty exhaust manifolds out there.

We swapped a 307 into a S10 using exhaust manifolds from a Olds powered Cadillac. I don't recall the year but the manifolds were tubular vs cast.

I believe they might use them on the HO 307s, but I am not positive.

 

[devious]

anyone have a link to info on re-building an olds 350? and also a good place to buy parts


again thanks for all the help