Rutger34

Hello everyone,

I am planning on overhauling the 455 2bbl in my '68 Delmont. I am already booked to change the single exhaust to duals. I know that I need to change the carb and manifold. I am curious what you recommend for both. What about pistons, cam, rods, valves etc. What about engine oil pan? Gaskets sets? How about ignition etc? I don't want my Delmont to be annoying but I would like it to be quite a bit meaner.

Thanks for your help!

455man

What's your budget? How much power you want? Is it going to be a street car? Daily driver?

Rutger34

I know it sounds weird but I don't really have a budget. I would like to keep in to a few thousand. I am a Service Manager at a dealership so labor is cheap for me. My Delmont is my Summer driver when it is not raining here (Calgary, Alberta, Canada). I will only be putting on a few thousand kilometers every year.

(edit) I would like to have enough power to keep those kids with the annoying cans on their civics in my rear view mirror.

442much

Oh, you mean the "grapefruit launchers".

Rutger34

You bet. Very annoying!!!

ThePackRat

What is the current condition of the motor now ?.

You should have no issues keeping those things in your rear view mirror on a stock motor.

bdub217

Well if he comes across a Nissan G-T-R he's in for a run....... They come stock with Twin Turbo V6 running 545hp. But if youre wanting to blow out the little wannabe rice mobiles with 240-340hp, you should be able to do that already with the motor you have. I think your stock 455 has 310hp. I believe the 4bbl model has 365hp.

Rutger34

The motor is in reasonable shape. I don't have much problem with a lot of cars and trucks with what I have. I just figure that if I am going to fix some oil leaks etc. I might as well go nuts. I love "sleepers" and I think the old girl will make a great one. I would love to pull up to one of those GTR-S's and roast him!

bdub217

bigger cam, 4bbl carb, performance intake, bore out the cylinder walls, add root supercharger...... lots of stuff you can do all depends on money.

and you can keep the exhaust whisper quiet all day and still be pushing out tire shredding HP

ihengineer76

I know you said that you don't have a set budget, but you do need to decide what you want from this motor. Do you want to have to run premium, or do you want to be able to run regular? Low end torque, or more hp in the upper RPMs? Wild or mild? All these things should be decided before you start because all the components need to balance and work with each other to get the full potential out of the motor. Too many time you see cars all set up with "go fast" parts that perform terribly because none of them are really compatible with each other. Set up some definite "wants, and many of the guys here can help with the specifics. You can also get many of the parts for the build from these guys at probably a better price than you get from parts suppliers. Have fun!

bdub217

Another thing to consider would be changing the Differential Gear Ratio. If it's a tall gear atm, you could go a bit shorter to gain a lil off the line.

Rutger34

Thanks for the advice everyone. I am looking to get my car to sound lumpier, quicker off the line, premium fuel does not bother me if I have to use it, this is my toy. I am not interested in super chargers or blowers. For a budget, say $2500.00 for starters.

Any help now?

ah64pilot

X2, I couldn't have said it any better myself.

You are going to be hard pressed to rebuild the engine for $2500. Plan on $1800 just for the bottom end - bore, hone, new pistons, rings, cam bearings, bearings, line hone, surface block, balancing, assembly...these are all things you might need or consider doing when you do it.

Now add the new intake, carb, cam, lifters, pushrods, rocker arms...we haven't even touched the heads yet and you're well over your $2500 budget. Either increase your budget or take shortcuts...I suggest increasing your budget or you might waste your money if something breaks.

m371961

If you are looking where to start, run a compression test. If compression and oil pressure is ok, just start with intake, 4 barrel and dual exhaust then save up your money and see how far you wanna go. Fast costs money, how fast do you want to go?

droptopron

Your car is heavy so I would favor building for low end torque over high horsepower. I would look at a dual plane intake and a cam with a power band to match. Most def take a look at the rear end. I am not sure but I think you car has a larger type o that will be hard to get parts for so you may need to swap for a set up out of a Chevy. Biggest performance gain i've seen in my car is swapping from a 2.56 to a 3.23, and 3.23 is still mild and great for the highway.

Eddie Hansen

I know you said you don't have a set "goal" and you mentioned 2500 as a ball park figure, I think seeing what you have and what condition it's in is a great idea, compression test, it would be worth doing a plastigauge check on your bearings and see if you can get away with a freshening instead of a whole rebuild. even a 2 bbl 455 will probably have a compression ratio of 9-9.5 to 1 which is about as High as you want to go,with the quality of gas and no additives. Without additional work a stock 4bbl manifold with a quality built q-jet would be fine, get the right exhaust manifolds for a true dual exhaust, you could perhaps upgrade the cam, lifters etc. I would think you have the small valve heads which will probably be ok on your build, basically I am saying make the best with what you have, if your tranny is good perhaps a shift kit, improved ignition etc.

some parts ideas I purchased a milodon stock pan, which actually holds 1 quart more oil this was a good investment IMHO, quality cam and lifters, perhaps with a spring kit and have the heads looked at. you do need to watch for "mission creep" also known as "might as wells" or the dreaded MAW. If your goal is to have a nice cruiser in my opinion a freshening up of a healthy motor is the way I would go. I got caught up in the might as wells for my cutlass 455 build, eagle rods, forged pistons, harlan sharps, restrictors, better oil pump, roller chain, etc etc etc and all I want is a nice cruiser LOL.... my cost was about 5500 with all the parts and machining, and I was looking for an honest 400 HP..

I think you can do a lot with a little but you need to see what you have first, I think a junkyard dog kind of build will be fine for the kind of use you are talking about as long as the vitals on the engine are within spec. That is where you need to start.

Rutger34

Thanks for the input everyone. I spoke to the guys at work as well and they had the same sentiments. I am going to get a new carb and intake, new cam and dual exhaust to start. I am looking into a new set of rear gears as well. I will go from there.

I love this place!

bdub217

The cheapest would be to start with the rear gear change, honestly i think this will blow you away at how zippy the car will be after say throwing in a 8.5" with 3.23's or 3.42's even. Don't forget you'll need the Speedo adjusted accordingly.

Rutger34

Will do. This is right up at the top of my list.

47 Convertible

I would add a limited slip rear carrier along with 3.42 gears and go to 8 inch rear wheel and tires if they will fit inside the fender. All will help with hook up when you get on the gas. An open rear end will just sit and spin. Have the transmission set up for a firmer shift and save enough at the end for a good wheel-dyno tune. You might find 10 or more HP just in that.

I would stick to exterior engine mods if the internals are in OK shape. Used dual plane Edelbrock Performers are around on the Internet as are headers. Rebuilt or new 4bbl around 800 cfm and the 74 and newer point-less distributor.

Just my nickel's worth of advice.
Jerry

oldsmobiledave

Exactly where will he source an 8.5" rear end that will bolt into the Delmont body? Please explain.

The early Delta speedos runs off the front wheel. I presume the Delmont is the same. So there is no need to change or adjust anything since a gear change in the diff has no effect on the speedo accuracy.

droptopron

I wouldn't call setting up or swapping a rear end cheap either.
IDK the answer but if you source a 12 Bolt from a F/S chevy does it use the same internals as one from a Chevelle?

oldsmobiledave

No. Big car Chevy 12 bolt & A body 12 bolt internals are different.

Stevec

I recently did some work to my 400 rebuilt heads,roller cam,roller lifters,timing chain,oil pump,intake,carb and electric ignition. It runs good but something tells me the 43 year old bottom end is not gonna make it,I don't beat the crap out of it but I do drive it hard.

I am now in the early stages of building a 455, I wish I just did it from the the beginning.
It doesn't take much to wake up a 455 but it does take a little $ to make it last, for me I will never rebuild the top half of an engine without working on the bottom end I'm convinced it won't last especially if you want to smoke some of those civics. Imho.

As mentioned earlier fast cost money especially when your building an Oldsmobile!

ThePackRat

Since you say the motor seems to be in decent shape ...
(may want to confirm with a compression check)

I think I'd concentrate on eliminating the leaks & just make what you already have more "efficient" in getting it's power to the rear wheels.

This is where I'd start if it were my car .....

Engine :

New timing chain & gears.
4bbl intake & carb swap & make sure the carb is built/set up right.
A decent dual exhaust setup.
And HEI set up & re-curved for that motor.

Transmission & Gearing - (3) choices ... pick (1) :

1 - Swap to a 65-67 "Switch Pitch" type setup & torque converter with some 3.23's to improve things out of the hole.

2 - Keep your current TH400 ... & get a better torque converter (something with @ 2400 stall) with some 3.23's to improve things out of the hole.

Or ...

3 - If you really want to go all out & throw some 3.73-4.10's in it with a built 200R4 with @ 2400 stall TC.

Now 4.10's might seem excessive even with an OD trans ...

But it is a big car that needs a taller tire to fill up the wheel wells.
(which means the effective axle ratio to the ground is less)

I'd also think about a trans cooler regardless of which choice you pick.

Doing the above should make the car feel like it shed quite a few pounds & give it some more punch off the line as well as feel more responsive all around.

Perhaps that would be enough for now or awhile ?.

If it's not & you still find yourself wanting "more" out of it & decide to put a cam in it down the road .....

As long as you kept it fairly mild (strong emphasis on mild) which would still improve on 40+ year old cam technology if chosen correctly .....

I don't feel those TC stall speeds would really hurt you.

bdub217

I never said anything about a direct bolt in. It would take some work to achieve, but could be done.
Ah nice to know =) That makes things easier.

oldsmobiledave

Well with that logic he might as well put a Ford 9" in it....Now I am not saying anything about a direct bolt in....It TOO would take some work to achieve, but could be done....

My442

500+ HP in an Olds 455 will cost $12k from any of the top engine builders.

G Money

I have bought a 455 olds 1968 Fa block and am looking to build it wanted to do a few things like hon and bore over 30 what i would like to no whats the best pistons to go with am also wanting to run a cam big as i can go without having to change heads heads are c heads and i will be spending around $700 up to 800 on building them