Increasing my 455's horsepower

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I have a 74 cutty with an olds 455..

I don't know that much about cars I must admit, but I was wondering what would be the best engine mods that could boost my horsepower a bit?

Also where can I find information on this motor at? Like stock horsepower etc.

thanks alot

posted by  mrfreshnklean

uhm, 4-barrel carb, low-restriction exhaust. that's actually all I can think of besides blower. but that's a real problem with fuel economy.

posted by  Satty101

First I'll assume you mean a Cutlass, a "Cutty" is a sailing ship, a spoon, a pipe or an Irish whore.

You'll have to be just a little bit more specific than that. What kind of condition is it currently in? Is it the original engine or is it something that's been dropped in? Define "a bit". Why do you think you need to boost your horsepower, are you sure it's not torque you're after? How capable are you of doing the work yourself? What is your budget? Define "best".

Only three ways to increase power? Why don't we get some facts before jumping to conclusions?

posted by  vwhobo

an irish whore....interesting.... :laughing: :doh:

posted by  SuperJew

those where just the ways I could think of off the top of my head (which is amazing there's anything there in the first place) And I have done some research in the past because one of my friends has a 72 Olds Cutlass and I wanted to see some of the horse power upgrades as well as torque. those 3 were the only I could think of at the time and wasn't about to go look them up at 11:30PM. Too tired for that. I'm not trying to argue with you, I just wish you would take into consideration some of the other possible reasons I would give that answer.

Ohh yeah, btw, my friends Cutlass has a 350 Rocket so are there more modifications for it than the 455? Or are they really around the same? (I know, really general question but got curious)

posted by  Satty101

Unlike Chevy, Ford, and Mopar, an Olds V8 is an Olds V8, there is no small-block or big-block. Being as the architecture is the same they will both respond to the same modifications. Keep in mind the 350, having smaller and lighter rotating and reciprocating components will accept more rpm than the 455. The other side of that is the 455 has larger crank journals making it stronger and has space for larger valves allowing more airflow.

So to answer your question, yes they are very close to being the same. That being said you can get more power for the same price with the 455 AND it'll bolt right in place of the 350. Is that enough info?

posted by  vwhobo

plenty. thank you.

posted by  Satty101

ITs the stock olds 455 in there... runs great.. Previous owner put a high flow K&N and thats it :). I dont think I need torque, the tires smoke for about 75 feet as it is.

The real problem is the wheels I have on there... 285/30/20's.. (Sorry) I basicaly want it to be as fast as it was when I had the cragers on it.

posted by  mrfreshnklean

Well gee whiz, I think you may have just answered your own question. And just think, with some old Cragers on it the car will look better to boot.

posted by  vwhobo

Would changing the rear end gears improve this any?

posted by  mrfreshnklean

Changing your "rear gears" will in no way effect your horsepower production. First you need to determine what your question actually is, then you need to answer the questions I posed to you earlier in this thread.

posted by  vwhobo

when i refered to rear gears i meant is there a better gear ratio to use when you have bigger rims.

1) condition is great.. functions perfectly. Motor is bare, just the fan and the alternator (Should I bother with an electric fan?)

2) stock olds 455 w/ TH400 automatic

3) I just want it to be a little faster. Comparable to when it was on the cragers. Its not going to be a drag race car, its a show car... Just wondering what little mods are to boost my HP by 50 or so.

4) I've got connections.. Would rather not replace the cam though.. Something I can do at home with a tool box.

5) budget is $500-1000

posted by  mrfreshnklean

This would be the perfect time for you to go to the Gearhead Garage and read the latest article (also an excellent time for me to plug it).

Fifty horsepower is going to be a tough job with bolt-ons on that engine, because of the low compression and the smog heads. Without replacing the cam you're seriously limiting yourself, and even with a cam swap it'll be tough. About all you have left is the intake, carb, headers and exhaust. That right there will use a good portion of your $1k and get you maybe 30 or so hp.

If it's only for occasional use you might be money and labor ahead to go with a low budget, low hp, plate nitrous system. As long as you run small pills you won't do any damage to the engine or drivetrain. In my opinion the best and most cost effective way is to get rid of the dubs. The car will go, stop and turn better plus think of all the money you'll have to put into performance upgrades.

For those of you who have no idea what kind of car we're talking about;

posted by  vwhobo

Is there a specific nitrous system / HP you would recommend?

It just killed me when my friend passed me in his stock crx

posted by  mrfreshnklean

personaly, I think NOS is over-rated thanks to The Slow and The Curious. The way I see it, either ZEX or Nitrous Express are the 2 to consider. But this is all my opinion. VWhobo may see hings differently and I impatiantly await his response.

posted by  Satty101

Honestly, for your application I would have to go shopping. Nitrous Oxide Systems (NOS), ZEX, Nitrous Express, Holley, etc all make good systems. Your best bet would be to call some tech lines and see what their recommendations are for your car, how complete the kits are, pricing and so on. You might even scam a deal on e-Bay or check your local dragstrip.

posted by  vwhobo

NOS is a crock of shit in the real world....short bursts arent worth a damn on the highway. its all about turbo/blower/big engines. :guns:

posted by  SuperJew


posted by  mrfreshnklean

Not when your "racing" from light to in the "real" world.

posted by  BavarianWheels

hey man, i just got my hands on a 1970 olds 455. im dropping it into a 72 cutlass.. i bought it from a friend of mine who runs his own shop. Its dynoed at 415 hp \ 480tq. it cost me 2000 cdn. and the guy gave me a deal.. i'd recomend a new set of heads.. 74 was a brutal year, the cam would help too.. anything form mondello performance.. new grinds KILL the old ones. umm bigger carb? i got a 850 deamon.. so yea theres tons of stuff out there

posted by  Cutlass455

I have a 1976 Buick Electra 225 Limited 4dr Hardtop with Vinyl and it is totally stock. I have the GM big block 455 V-8 with a Rochester Quadrajet. Now, being a 1976 455, it is de-tuned from the older late 60's and possibly early 70's and made to run on 87 octane. Lower compression, etc. The engine probably has no more than 220 hp or so stock, but it fairs well with torque. I recently took it to a guy 200 miles away that I know who does excellent custom exhaust work and I had him install custom "true" duals for me. He took off the pancake catalytic converter and ran 2" stainless pipes all the way from the flanged manifold bolt-ups to the rear bumper with polished stainless slant-cut tips and painted welds. I have NO catalytic and I have two high performance Flowmaster 40's welded in racing style equi-distance from the driveshaft and rear differential under the rear seating floor-pan. The sounds is spectacular and the power gains were noticable by no question. Someone was talking about Low resistance exhaust....well I've done it and it works. I would say I probably gained 15-20 horses easy and no telling about torque...AND it is a stock V-8 455 with no other mods. I get a hard-on every time I fire the engine and she sits there and loupes like a 396/SS with a cam. It's amazing what 500 bucks gets ya. Nevermind what you hear when you depress the pedal. :laughing: Who the **** needs a woman when you've got a big block with a HOT exhaust system? :clap:

posted by  cmeseadoin

And what are you doing with the "hot" exhaust system that you apparently also do with a woman? :doh: :banghead:

posted by  BavarianWheels

With the HOT exhaust system......get your sick mind outta the gutter. :screwy: I LOVE listening to it. As for the women, not a thing with them either. :laughing: Made your head hurt didn't I? :thumbs: :thumbs:

posted by  cmeseadoin

i hate you... first you call it nos then when talking about brand names you say zex and nitrous... WTF nitrous is the chemical and NOS IS THE BRAND.@#%@#J!#@^@!#

posted by  Arthur


There are several options for INCREASING HORSEPOWER, however most will put a giant sized crimp in your wallet; just ask any INDY and NASCAR team owner.

One popular option on the market is "the chip." Unfortuanately, the computer chip has several monumental draw backs:

1) The chip will set you back $400-500 for a mere couple percentage points increase in horsepower.
2) It will immediately VOID your warranty, so adding the chip to a new car can end up costing a lot more than the purchase price.
3) Finally, there's only a minimal increase in horsepower.

Now here's an option that gives you a very hefty bang for the buck and double digit increase on RPM without breaking your bank on a mechanic. Infact, in the long run you will actually save money by additionally increasing your miles per gallon.

Check out MPG Technologies,

Racing teams have used a variety of MPG Technologies products! Approved by the Federal Aviation Administration for use in aircraft, MPG Technologies products have been tested by the US Department of Energy, Franklin Research Group, NASA and Consumer Digest.

"We were skeptical at first, but it turns out that the product does exactly what the manufacturer claims."
Consumer Digest

The engine treatment has been tested worldwide by universities, military, government and independent test facilities have shown an average 17.5% increase in horsepower.

Official Test Results
Reduced Friction 12.6%
Improved Horsepower 15.5%
Increased MPG 17.5%

MPG Technologies backs up their claims with testing and offers some revealing information on other products on the market

As the primary sponsor of the Long Beach Gran Prix under the LubraLon label their treatment set the pace for the industry. Emissions and fuel treatment significantly reduces toxic emissions. The transmission and gear box treatment can save thousands of dollars on rebuilds.

They have products for Car & Truck, Boat, Plane, Small Engine, Motorcycle, Heavy Equipment, Compressors and a variety of other mechanical engines.

posted by  LetsGoRodeo

I think your exhaust man screwed you on pipe size. You should be running no less than 2.25" duals and 2.5" duals would be acceptable. If you had a true dual system of 2.5" I think you would have been much happier.

Just to give you an idea...your 455 is running no cats and dual 2" pipes all the 302 is running a 2.5" h-pipe(no cats)with dumps directly after the mufflers(DynoMax Super Turbo). I can't tell you how much hp and tq I picked up when I put that system on (versus the previous system-no cats, 2" mufflers with tail pipes). I can tell you it was so much of a difference it's just plain silly. I opted against installing tail-pipes on my current system so low-end torque suffered slightly but it made huge gains in the 3000-5500rpm range. My engine is rated at 225hp and is probably putting out much more now...I designed my exhaust system with 2 things in mind...keeping it quiet and having the ability to run up to 400hp before needing to bump up in pipe size.

posted by  Sick88Tbird

F*cking junk, that's twice in one night.

posted by  vwhobo

ATTENTION ALL MODERATORS. Here is an example of the trash you shold be getting rid of instead of active conversational threads. This individual was brought to the attention of an unnamed mod by yours truly. Unfortunately they only had tim to delete one of his posts instead of all five as requested. These perpetrators are extremely easy to find and identify with just a modicum of effort. If you have any questions I will be happy to explain how... If you have the time.

posted by  vwhobo

I would first get a catalog and tech manual from Mr. Oldsmobile himself... Joe Mondello. I believe he helped Edelbrock
develop these heads...
Who is also building some awesome manifolds now...
And some excellent carbs... check out the 1910...
And the catalog is free...
I would look into ignition, exhaust upgrades, and the above items at...
Both of which offer free catalogs.

Bore centers from smallblocks to bigblocks are the same, as are the bolt paterns. SB heads will bolt to BB cylinder blocks etc. But causes some problems with port alignment/size. I think some aftermarket heads for SB's had ports nearly the size of BB,s etc... Big blocks are about 1 inch taller, and 1.5 inches wider... So the big manifold is wider, before the selection of BB manifolds got so good, spacers were used on big block engines/heads and, more plentifull, small block intake manifolds. Not a big item any more...

This all just leaves alot open to a hot rodder on a budjet, who isn't afraid to play with the combo.

Oldsmobile "C" castings, from the late 60's are about the best flowing heads around. There are better, but much more rare. Definately use a HEI dist., if you haven't already done so. New, modern cams go a long way to improve performance, but watch out for the non-adjustable valve train. Stick to a hyd cam, from a bigger name, don't get a cheap re-grind, the reduced base circle will cause valve train problems.

You could get 50 hp easialy, A good HEI dist., wires, fresh plugs, aftermarket intake, new/well tuned carburetor, headers, and duel exhaust with free flowing mufflers.

Still, no matter what, get Mondello's catalog! Olds had an oiling problems I found out after I spun a rod bearing in my '71 455 (doing do-nutz at the mall, 6,000 RPM sounds sooo goood, but it'll never last!) When I was researching my rebuild, I got Mondello's catalog, 19 years ago!
He explains the interchageability, weaknesses, and strengths of the Olds.
The catalog I had even went into the 350 olds diesel, how to build a 440 drag SMALL block out of it, 425 BB crank drop in, and thick cyl walls to bore out! Put a 350 rocket air cleaner on it, and go street racing! Who would know?

If you do the research, you will find tech articals, check the news stands every week, Car Craft is a good one for Olds performance articles.
Also, go to the public library, and do a periodical search for Oldsmobile, some, and many librarys are cool enough to keep decades of car mags!
I photocopied lots of vintage tech for 3-4 bucks!

Do your homework! you'll find what you need!


My first car was that '71 Olds...I've owned too many GM's to count.
Got 8 SB chevys in the garage, along with a '76 Vette, 3 Chevy's in the driveway, one in the boat, and a Buick 455 on the way!

posted by  Wildman-Dan

I like modello for parts, they havent messed anything up on my in shipping or sending the wrong part, and for olds parts they arent too pricey.

i have a '70 455 in my 64 442 and i have it bored .060 over, blueprinted, and im not sure, but if you can get an X-Force Exhuast for your year olds, but if you can highly recommend them.

i have 2 olds right now and i have grown up with them all my life, you wont be disappointed with the power you can get, the specialty parts may be a little harder to find then for a chevy, but its worth it.

posted by  Rocket442

Where did you get your connecting rods for that engine?? X.X

posted by  Leuthesius

My last musclecar was a 1970 442 W-30. These engines were good for approximately 440hp stock. My suggestion for more power in a '74 Olds 455 is to consider replacing the heads as others have mentioned. My F casting '70 W-30 heads were great heads but good luck finding some now. The C castings are also very good, but getting rare too. I am considering building another Olds 455 and would be using the Edelbrock aluminum castings. Car Craft did an article on the Olds 455 using these heads, a Torker intake, 750 demon carb, comp cams XE274H camshaft and hooker headers. Results were 496 hp and 559 ft lbs. New heads are somewhat pricey, but you'll never get big power out of the stock '74 smog heads.


posted by  DPelletier

Oh, and if you ever find a '68 - '72 455 Toronado engine, they have the big valves, too (same as the W-30's). Oldsmobile definitely has big blocks and small blocks although the blocks are physically the same size except for the taller deck height of the big blocks (and correspondingly wider intake manifolds). 307/330/350/403's are small blocks and 400's (both 39 degree and 45 degree bank angle engines), 425's and 455's are big blocks. Pontiac 350's on the other hand are big blocks.


posted by  DPelletier

Since this thread is talking about enhancing Olds 455's, I am looking for some tips/advice on fitting this big block motor in a rusted 1979 Chevy Scottsdale 10. My dad has two of these old monster motors (From two '76 olds 98's), and I have been told that the bell housing and the motor mounts are WAY different from the Chevy 350 and 454. Does anyone have any advice on a CHEAP way to make things fit? My Scottsdale is a rusty piece, and will never see a license plate again (It's is just an old farm truck).


My dad wants to put the other 455 (in much better shape) into a 1967 Chevrolet two ton, which is registered and used for hauling cattle/grain/lumber on a regular basis. Under the hood there is enough space to sleep beside the straight-six motor :screwy: , yet our local mechanic still says the bell housing won't fit :ohcrap: .

Are there any mounts that could be made/bought to make it match the frame, and PLEASE, how can the chassis fit the tranny withought saws all on both the trucks mentioned? I also hear the oil pan shapes differ between the Buick and Olds 455, and the Chev 454 :doh: . Can I use the motors that I have?

Thanks :thumbs: :


posted by  Chopper_262

Well there is a way and yes the belhousing and motormounts are different on an Olds and a Chevy. I'm not sure why you'd want to spend the time on a rusty truck that will never be licenced, but.............

early 80's GM trucks with the 5.7l diesel utilize an Oldsmobile 350 conversion. These trucks have the appropriate tranny, motormounts, etc. Since both big block and small block Oldsmobile engines share the same motormounts and bellhousings, substituting a 455 in place of a 5.7 diesel is very easy. These trucks are getting harder to find these days, but since the 5.7 diesel is generally considered the worst diesel ever to be installed in a light truck, they aren't exactly "in demand". You would need to find a whole parts truck or you could find the correct transmission and buy the factory diesel motormounts.


posted by  DPelletier

I am building a olds 455 and im running a howards 4/7 swap cam with a 581 lift. Is this to much cam for this motor i will also run a set of edelbrock aluminum heads, but my question is what kind of temp will it run with the A/C on?

Mr. olds   13 Nov 2012 05:57

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