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 455 in place of a 307?

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Posts : 107
Join date : 2014-09-20
Age : 67
Location : Venice Floriduh

PostSubject: 455 in place of a 307?   Sat Jun 16, 2018 8:04 pm

I just had a complete 455 Olds engine (carb to pan) land on my door step. How much trouble can I expect to run into if I try to replace the 307 in my '89 le sabre estate wagon? Tranny work? gear swap ? Buy or fab motor mounts?

The carb is pretty rough, will the quadraflush from the 307 work? what about the little computer box on the passenger side foot well?

Will the 2004R OD trans stand the extra power?

I only tow occasionally, will this swap be worthwhile? ie more low RPM pulling power?, better mileage?, lower cruise RPM? any engine mods I can/should do while the engine is on a stand?

OK, that's enough silly questions for now, thanks in advance, Paul
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Join date : 2008-11-05
Age : 69
Location : Littleton, NH & St. Simons, GA

PostSubject: Re: 455 in place of a 307?   Sat Jun 16, 2018 8:20 pm

Hi Paul

I owned a 72 Buick Electra that I bought when it was a year old.  It had a 455 Buick engine in it, 250 hp.  I believe it is different than the Olds 455, but not 100% sure.  It was a DOG with capital letters, not great gas mileage either.  

Hopefully the Olds 455 was a different animal.

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Fred Kiehl

Fred Kiehl

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Join date : 2009-11-13
Age : 70
Location : Largo, FL 33774

PostSubject: Re: 455 in place of a 307?   Sat Jun 16, 2018 10:57 pm

It depends on the state of build of the 455. If you have a stock 455, it may be just fine. You could step up to a TH400. It will probably bolt in, except for the computerized part of the carb, or if you change tranmissions. You may need a different crossmember for a TH400.

You should use a carb that will satisfy the needs of the engine. You can run a non computer carb, and ignore the dash warning lights. I do not know if it is possible to program the computer for the larger engine.

You could put a stand alone 4 barrel TBI on it and hook up whatever sensors your car wants. If you decide to change the cam, you can reprogram the computer/change injectors on the TBI to work with the new cam. Some of the TBIs will control a 4L60E, or 4L80E. A 4L60 is also possible, but you must make sure the cable is properly articulated, and adjusted.

As far as gears, we do not know what you have, so can not recommend any changes. It also makes a difference, depending on what you are going to do with the car.
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Posts : 42
Join date : 2016-01-05

PostSubject: Re: 455 in place of a 307?   Sun Jun 17, 2018 9:04 pm

ive done this half a dozen times at least.a 350 or 403 would be easier but a 455 is super easy too.all the 307 brackets & accessories bolt on to the 455,you will need a spacer between the alt & ps bracket & another on a/c bracket.motor mounts from 307 bolt on to 455,you might need longer belts.forget the 700r4 or 60e theyre junk get your 200r4 built by a good builder that way you don't have to mess with driveshaft length.get the rad for a 350 diesel or a real good 4core rad.the diesel rad is huge use it if you can find the shroud for it.my wifes 89 caprice has a462 olds in it ,I have a howe racing aluminum rad in it using a stock 307 shroud it never goes over190 f even after constant beatings at the drags or in traffic.the exhaust manifolds are the biggest problem,the 307 manifolds are too restrictive even for a stock 455 & the 455 manifolds (the passenger side mainly)hit the fire wall.use sanderson headers # 0351 they work perfect ,you may need to trim upper control arm mount bolts on r side to make them fit & on some cars ive had to move steering column a little to the out side(easy just have to slot lower mount plate & push column over).I have used the sandersons on my 92 occ with a 403 olds too.message me if you need pics or any more info.disabling the c3 system if the car has it is easy too.you will love the power & a couple of people ive done these swaps for claim they get better mileage too
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phantom 309

phantom 309

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PostSubject: Re: 455 in place of a 307?   Sun Jun 17, 2018 11:11 pm

In answer to your question what should i do to the engine while it is on the stand,..

In my opinion,.. alot would depend on what year the 455 is,.
Things i would do,.steel cam gear and new chain, plug the ehaust crossovers to the intake,. And definitely find an old edelbrock torker intake. Or better still an offy 360 intake,. Put some umbrella seals on the valves,. Buy an edelbrock 750 vacuum carb,. definitely use headers.
Any ither mods would depend on the year of the motor.
You'll end up with over 500lbs of torque,. Definitely will tow.
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Join date : 2010-06-23
Age : 44
Location : Round Rock Texas

PostSubject: Re: 455 in place of a 307?   Mon Jun 18, 2018 11:33 am

I did the Olds 307-to-Olds 350 swap on my 88 Cutlass, and I never could make the stock computer-controlled-carb work correctly on the 350...I did try for a week or so before getting frustrated and changing plans.  

I ended up removing the entire computer, harness, and pulling the Check Engine bulb, and going with an Edelbrock 650 carb and Performer Olds 350 intake from Summit Racing, an aftermarket distributor, and installed the aftermarket lockup kit for the stock 200R4 trans.  I also removed ALL the smog-related vacuum hoses, smog pump, and EGR nonsense.   That solved EVERYTHING and the Cutlass ran like a scalded dog after that!

I re-used all the stock brackets, but did locate a set of Olds 403 exhaust manifolds and Y-pipe from a 77-79 Trans Am which are both larger and do not have the AIR line emissions bungs.   Even the Cruise Control bolted right up and worked fine!

If you live in the land of emissions, you SHOULD be able to keep your cat converter for visual inspections, but I would knock the guts out of it, and then just remove everything else emission-wise.    You will be shocked at how well it runs, how clean the underhood looks, and how easy to service the car will be.

OH and just to share, the 455 is just a bit larger externally than the 307 and 403, so I've been told you may have to notch the a/c evap box case to clear it.   The 307-350-403 are all the same size, but the 455 larger I believe.  

Good Luck!

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PostSubject: Re: 455 in place of a 307?   Mon Jun 18, 2018 8:35 pm

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Posts : 42
Join date : 2016-01-05

PostSubject: Re: 455 in place of a 307?   Mon Jun 18, 2018 8:41 pm

some pics of olds 462 in 89 caprice, not sure what I did to get multiple pics of same shot .sorry still trying to figure this picture posting out.a/c box is not cut,havent had to do that yet.i made brackets to adapt the chev serp drive to the olds engine.
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