Bernhard

Dose the small block Olds make HP and TQ more efficiently than a 455,HP/TQ ratio?

Ring seal SBO V BBO 350 V 455 is one better than the other?

At what point dose ring seal and over bore become a problem in a 350 and 455 .030,.060 above .o60?

Over heating problems 350 V 455?

Rpm 350 V 455?

Cost 350 V 455?

Builder skill level 350 V 455?

Hp loss do to friction 350 V 455?

$$ v HP/Tq 350 V 455 ?

What engine will live longer 350 V 455

What engine would be more NOS friendly 350 V 455

MPG 350 V 455 at $6.00 a gallon for the good stuff it is a factor


Above questions are based on a street engine.

Budget $5000 long block

Thoughts?

headers/starter/carb/etc are not part of build budget
Street engine no block filling /engine plates/etc

If there was a 3.75 to 4.00 crank on the market that cost around $400 to $500 would that tip the scale toward the 350 over a 455?

pogo69

go with the cubic inches...the 455 is the way to go... jmho

380 Racer

joe_padavano

Yeah, for a street engine, why do you care about making HP and torque "more efficiently", and exactly what does that mean anyway?

Look, for a STREET engine on a limited budget, starting the the largest displacement engine is the cheapest way to go. Again, a drag motor operates under a very specific set of conditions and you can maximize performance by matching gears/suspension/tires to the engine's power curve. Street driving requires the maximum flexibility possible - you don't always launch the car at 5000 RPM from every stoplight. You also don't want to have to constantly run the motor above 4 grand to stay in the power band. The larger motor will be more flexible and more fun to drive ON THE STREET.

Seff

What he means is does he get more power per cc of fuel.

I agree that the easiest way to have a fun driver with power is to up the displacement.

380 Racer

Like I said, my answers are My Personal Opinions. If more cubic inches is better, we should all build 496s. My car came with a 350 and I kept working with it. I bet most of you that preach BBs have never driven a warmed over SB.
First day out one season I dropped a valve.......total destruction! Borrowed a friends 461, around 9:1, used my cam, Torquer, and a 750 Holley. Car had too deep of gears and over converted but we were running 1/8 mile. I have an oil pressure warning lite that tells me when the engine hits 15 psi. That came on enroute back to the pits when it got hot.
When my engine was getting transferred from the gas block over to the DX, a friend asked if we could test his 496 ahead of different gears & converters.......sure! Again the OP didn't impress me going thru the traps and the performance (9.98 best) didn't either.
My 425 SB ran a 9.96 first day out, great oil pressure and shifting 200 rpms lower than the BB.
I'm sure somebody will come back and try to tell me mine is not a streeter.......well DUH. The principles and laws of physics are the same....X amount of HP to move X amount of pounds in X amount of time. Yada.....yada how about torque? Well you need torque to make HP, but if you only have torque, you won't get there very fast. An example my 425 produces 730 HP but it also has to produce 580 foot pounds of torque. Which is why it stands on the rear wheels on the launch but goes 1320 feet in less than ten seconds.
I'll say iy again........I really like my small blocks!!

oldcutlass

I agree with 380's and Joe's explanation on all the above, it's all about the total pkg. For the car show guys, that never race, nothing looks better under the hood than a BB.

z11375ss

Here's a video of my car. It has a SB in the beginning of it and a BB in the end of it. Day, SB. Night, BB. Butt dyno says the BB is the way to go for all around street car.

joe_padavano

Again, it's a STREET car, not a dedicated quarter mile car.

Oh, by the way, what's the displacement of your "small" block?

pogo69

smokey yunik used to say ''there's no substitute for cubic inches'' hate to argue with smokey

pogo69

nice video...makes me want to cruise

380 Racer

Well Joe do you expect me to run where I want to with a 307? I guess I want to go fast without having to worry about low oil pressure. Didn't have to install a main girdle. It's too bad that that is the answer for everything from you. I don't preach using a SB to everyone, whatever floats their boat. I sure do see many more BB having their self destruct buttons pushed rather than SBs.

Yes Joe my bullet displaces 425 cubes, but produced 730 HP with 580 lbs of torque. 1.71 HP per cube and 1.36 lbs torque per cube. Personally I'm very impressed with that performance. Who cares if it's not a street motor.

In other words "it's only a Street Car"

Octania

Does the small block Olds make HP and TQ more efficiently than a 455,HP/TQ ratio?
============
What is your goal? What final drive ratio are you going to use?

Over heating problems 350 V 455?
=============
Not if done right.

Cost 350 V 455?
Builder skill level 350 V 455?
===========
Meh, about the same.


$$ v HP/Tq 350 V 455 ?
===============
Pretty sure you get more power/$ from a BB. SB's can make power, but more extreme measures are required, and, again, if you did all that to a BB, you'd still be ahead.


What engine will live longer 350 V 455
What engine would be more NOS friendly 350 V 455
=============
Don't rule out the 330 and 425.


MPG 350 V 455 at $6.00 a gallon for the good stuff it is a factor
=============
Probably similarly dismal, but a lot depends on your final drive ratio. One option is the Turnpike Cruiser pkg- hiway gears, like 2.56, compression and high octane fuel for power and torque, and a cam that emphasises the lower end of the RPM spectrum. Top it off with a 2-bbl carb and you get superb streetability backed up by a pretty good punch when opened up.



If there was a 3.75 to 4.00 crank on the market that cost around $400 to $500 would that tip the scale toward the 350 over a 455?
============
For that kind of money you can get the 455 FORGED STEEL CRANK, or a 425 or 330 to start on- both of which sport forged steel cranks.

Nitrous? Get the strongest stuff you can get- forged pistons, etc.

Bernhard

[QUOTE=joe_padavano;493711]Yeah, for a street engine, why do you care about making HP and torque "more efficiently", and exactly what does that mean anyway?

A. 350 olds engine that makes 310hp .886 hp per cu

B. 455 engine that makes 350hp .769 hp per cu

Engine A makes more hp per cu thus more efficently hp per cu
Engine B made more hp

There are a lot of factors
455 bearing problems there are a lot of builders that have had problems
455 block weight width height only two header options
Rpm limit

It does not mean I will not build a 455 I just like to look at all my options,my brother and a good friend as well as my self are all looking at building Olds engines the more I can learn from others the better.I started a 403 build but after looking at all the negative results I have changed my mind.
Form a performance build or track only build from what I have read the DX is the smart choice.I have learned a lot from others that have been very good about what has worked for them and what has not.Will this make my build smarter and last longer I think it will. Thank you to all that have posted.Its like when I was in the trade best advice I got leaving trade school, shut you mouth and look and listen to the old guys they have a lot to offer. I did just that and thay made me a better bodyman and some made me a better person.

joe_padavano

Well, the O.P. for one. He's asking about a street motor. Your build is impressive as hell, but I wouldn't put it in a street car - at least not one I was driving regularly in traffic. You certainly understand the need to match the engine build with the gearing, tires, and use of the vehicle. Many less experienced do not and assume that what works in the strip is what they should run on the street. I don't know how many times I've seen questions about how high a stall speed converter they should run on the street, or thinking they should run a Powerglide on the street because that's what the drag cars run, etc, etc. This is a system engineering problem that you've obviously nailed but most people don't understand.

stressed1

You can build a small block all you want, just remember - it's only going to flow as many cubes as it is. Look at your motor as a giant air pump, because essentially that's all it is. Having a massive tall air filter, 1050cfm carb, and 3" or more exhaust isn't going to matter when you only have 3xx cubic inches. You will be limited. And my advice, build a pump gas motor. Paying $6.00+ will get real old real quick. You can make more power for pump gas on a big block.

captjim

My 9 to 1 355 ran 13.9 with a 3.42 gear in a 3800 lb car. It was dead nuts reliable, ran cool, fun to drive, and got 16-18 mpg. The same amount of $ and attention to detail in a BBO would probably result in high 12s.

But, there are advantages to a 350. It is smaller, which combined with smaller tube headers can easier to work on, especially in a G-body. The 350 in stock form is a better candidate for a little (key word, "little) spray. In some areas the cores are much easier fo acquire. Also, the drivetrain will take less abuse.

But from a bang-for-the-buck perspective, all other costs being relatively equal and performance being the primary goal, it is hard to beat the cubes.
Also, I agree with Stressed, a 9.5 to 1 468 will give you all you need, no reason to crank up the compression.

Bernhard

If I had deep pockets I would build a DX for the street no need for block filling/girdrle.Big inch in a small block package.I just don't think this is a straight forward build.
From past experience the 350 is more forgiving when being abused it might not make as much hp/tq as a big block. I'm with Captjim it has advantages over the 455.

I would love to see a 4.00 inch stroker crank that is set up to use off the self small block chevy rods.

captjim

Where do you guys keep coming up with this 4" stroked SBO crank????

Bernhard

After market crank there maybe one that still that makes it to market but looks to be well over $400.I have time so I'm going to wait and see if it does make it to market.I would love to have a square gas block 426 cu small block.Time will tell.

captjim

I have NEVER heard of anyone talking about introducing a 4.00" stroke SBO crank. Mark has a 3 year old post regarding a 3.75 crank, hasn't happenned and isn't going to, IMHO.

"I would love to have a square gas block 426 cu small block"

What in the world does this mean?

stressed1

lol

Bernhard

Bernhard

Gas block not Dx or Nascar block 1968 to 1975/76 gas block
Bore 4.117 stoke 4.00 square if you want to be picky very close to square
If my calculations are right 419 to 426 cu with a .030 to .060 over bore
I talked with one vender and there may be one that makes it to market, time will tell.
Talked = email in the last few days.

Bernhard

Are you a follower?

olds 307 and 403

Cool, I like the 4" idea over the 3.75". Time will tell. There was supposed to be direct fit SBO rods coming, never happened. I am doing my 350 with Procomp heads for now, then slowly doing the 403 stroker with girdle. I love the SBO, doubt a 455 would have out lasted my cheap 403 turning 5500 rpms. Of course the 403 didn't like it either in the end.

Bernhard

If the cranks make it to market there might be a 3.75 or 4.00 or both time will tell. They won't be cheep but if I can build a 4.00 inch stroke 350 that would = 419 cu/426cu gas small block. I don't mind parting with the extra $$. For the cost I would not buy a 3.75 crank, I would just stroke my 330 steel crank as I said before they are not going to be cheep.

Good luck with the build. I look forward to hearing about your procomp headed 350.

joe_padavano

So again, other than an inch of deck height (and the extra cost for custom crank pistons, and machine work - oh and smaller intake ports) what would be the difference between a 426 SBO with a 4" stroke and a 425 BBO with a 3.98" stroke? OK, fine, bearing diameter. Are you going to regularly run a street motor at high enough RPMs to care about this. Of course, you can build this SBO today with a DX block and a 425 crank, but again, for the STREET, why spend the extra money for the same bore and stroke?

captjim

^^^^^^^^^^ Good points. Also, what is the advanrage of a "square" engine on the street? The 350 Buick is square and certainly is no beast. The 455 Olds is undersquare yet runs pretty good. The 403 is grossly oversquare and yet makes a bunch of torque.

380 Racer

You keep talking STREET, so what are you going to do on the street? It's going to be a compromise if you want it tame enough to go get the groceries. Maybe you just want to smolder the tires? Or maybe long distance speed? Or maybe street racing? Street racing.....used to do it.......lost too many friends to it.........stopped many years ago.

As far as a 425 crank......why would I want to put a 40+ year old crank in my other wise new engine? My billet crank has 2.5 mains and 2.0 rods for less bearing speed. Joe it's guys like you that think the factory is still the best game in town so new parts will not exsist. I'm done with this thread.

Run to Rund

The BBO also has longer runners in the intake manifold for more torque. So long as the power level isn't so high that the block main saddle support is marginal, there is no need for all the cost and work to use a diesel block. I have a bunch of those 45+ year old cranks, and none of the metal has evaporated off them yet, lol. I believe they are plenty strong yet, especially for a street build, or even tens in the quarter. . .sure the bearings are big and the crank is heavy at 76 lb so there are better combinations for racing. For street, or street-strip, I see a lot of advantages in cost and ease of building the combination to using a BBO.

joe_padavano

What I'm doing is responding to the original post that started this thread:

I don't argue that a build like yours is a very impressive drag motor. That's not what the O.P. was asking about. Believe it or not, street motors rarely see more than 5000 RPM. Mid-range flexibility is far more important than peak HP and torque numbers. And sorry, but bolting together factory parts will be less expensive than custom aftermarket parts for this application. I wouldn't advocate building a drag motor using all factory parts. I have no problem building a long-life, fun-to-drive street motor that way. These are very different problems and require different solutions.

Bernhard

For me street car = street strip weekends only,summer only,
After I over rev my engine heating up my tires I don't want a pile of metal bits going through my engine.There are lots of 455 builds that live and make big hp/tq numbers, there builds work and they are doing somthing right.I have spun rod bearings in big blocks my self there are just to many home built big blocks that fail as well as from engine shops.There seams to be many machine shops that do not know how to turn a 455 crank,or poor grade of gas that takes the bearings out of these engines. There is nothing wrong with building any big or small block Olds engine. I just wan't to look at all options.

I have time so I'm going to see if this 4.00 stroke crank makes it to market
As far as cost the 455 is cheeper only if you get the oiling, clearances and what ever else right the first time.

captjim

How is that different from any other engine? Use good machining practices and stick to the .001 of clearance for every inch of journal and it should be fine. IMO, the 455 will cost a tad more to build, it probably won't be cheaper.

J-(Chicago)

I think people have gotten too caught up in frankensteining the living **** out of Oldsmobiles lately. Mix n match this shiny crap with this other misc shiny crap, and create a conversation piece comprised of parts from all 9 levels of hell.

We are talking street/strip here are we not?

Stock or eagle rods, and forged flat tops will get pretty much any street/strip goal achieved in my opinion. With an iron intake and heads to boot. The aluminums will save you some elbow grease if you like.
If you want 600 horse, it's not a friggin street car.
You would grease radial tires down to the rims anywhere you went with a 350 horse olds.

Bernhard

Why are there so many 455 that fail? When I see engines that fail with few miles on them because the crank was .0005 to tight or from low grade fuel or no oil etc it makes me think twice.

HP/TQ per dollar the 455 is cheeper
You can use off the self piston,rods and stock stroke crank and still make
good hp/tq

If I go with a 350 gas block it will have a stroker crank and custom pistons thats why it will cost more than a 455 build. If I build this engine it will cost more than $5000 I'm okay with that.

captjim

This makes no sense to me. How can the crank be .005 "too" tight when .0030-.0035 is acceptable?

IMO, more 455s fail because more are build and beat on. What is the ratio of racers running 455s vs 350s? Also, many guys cheap out on machine work resulting in engines that are too tight.

Any engine that detontes may fail, Olds, Chebby, Ford, whatever. Using crappy gas with high compression and the wrong cam will cause detonation.

Bernhard

If you look I fixed my post before you posted this post so I caught my own misprint. It was to read .0005 not .005

Some OLDS engine builders run tighter some run looser when the engine fails its becuase it was not built right with there clearances or it was bad gas/low zinc oil /stock rods/rpm over5000/heavy pistons/heavy rods /stock engine mounts were used=should of used a plate, machine shop was ****/ chevy specs, wrong cam,two much comp,not enough comp,wrong bearings,wrong balancer,wrong pan,wrong oil pump,restrictors yes/ no ,etc.

Just saying

captjim

You keep saying the same thing. ANY engine will fail if tolerances are incorrect, inferior machining practices are used, and a poor combination of parts is used.

captjim

Not true or my "quote" of you would have been .0005, not .005. Also, I find it hard to believe the the reason an engine lives or dies is a half-tenth of bearing clearance.