Goofy

I've been looking online about the olds 350, lots of people are saying they are not worth it. Cost too much bla bla bla. Well chevy 350's are a dime a dozen yet an olds 350 rocket are hard to come by. To me I prefer the olds over the chevy. My question is when I rebuild the olds 350(400 HP) is there any difference than a 400 hp chevy,so which is better?

80_cutlass

At that level of performance, either one is going to cost you. Is there a reason you are hung up on that number?

sb

Goofy

nope just want it around there. Want her to move. with 400 can still run pump gas

70 cutlass s

If you want that level of power you would be better off going with a 455.

One its easier to get more power out of a larger engine.
Two if you plan on driving it on the street. A 350 built at that level is going to require more gear, stall conv., and not going to the very street friendly.

If you want to go with a 350 Olds. Building a nice engine with plenty of torque is what you want to do. If you want to run pump gas 9.5 to 1 compression is all you need. You don't need more then 10 to 1.

The reason people a lot of people use the Chevy is because you can buy it already to go and drop it in.

Goofy

I was always kinda stayed away from a big block cause of it can't take the RPM. Now is this true

Oldsguy

It's really a function of math. A larger engine has more rotating mass, this usually limits the maximum safe rpm attainable compared to a smaller engine. However, a larger engine (in our case a BBO) generates more torque and that torque is apparent at a lower rpm. Horsepower is a function of torque multiplied by time, so if either is greater you have more horsepower. Big blocks generate more torque over a flatter curve that starts earlier and ends earlier (rotating mass) than the small block. But the small block will spin higher. Of course, with enough money any one of those two variables can be overcome. With the same amount of money to spend it is just easier to get more horsepower out of a BBO. There are people that like big blocks, and people that like small blocks and they all have their reasons. You could be in either camp and be right...........................as long as it's an Oldsmobile .

Goofy

Well first thing where would you find an engine and 2 what are they worth now a days. They are getting rare to find so I imagine they are costing more money

olds425

I have a mild '74 350 in my '42 Chevy and it is pretty fast as is. I took one of my old car buddies for a ride a couple years ago and he was amazed at how quick my car is. He actually said I thought Olds motors were slow but this thing really gets it on. I also have a Chevy 350 gathering dust while I am saving to swap out my Olds 350 with a 455 I am going to build for it.

joe_padavano

Lots of people on the internet are clueless idiots...

The Olds 350 has a larger bore and smaller stroke than the Chevy 350, which should make it a BETTER performance motor. The biggest problem with Olds motors is the heads. Unlike Chevy motors, aftermarket Olds heads are limited in selection.

cutlassefi

x2!!!!!!

olds425

I sure like my Olds 350 than any Chevy 350 I have ran.

67 Cutlass Freak

The 350 Olds engines are probably the easiest to find. Finding a 1972 or earlier, with better heads is a little more challenging. If you are willing to run a mix of racing fuel you can bump up the compression to 12:1 and make 400 HP fairly easy. As stated before the heads are a limiting factor. You should do some research on aftermarket heads or at least consider porting the cast iron ones. You should keep the rotating assembly as light as possible and deffinitely have it balanced if your gonna spin it past 6000 RPM. The best advice I can give you is talk to a reputable OLDS engine builder.

Olds64

Oldsmobile engines are better than Chevy engines because Oldsmobile engines are made out of iron and Chevy engines are made out of congealed toothpaste. That is why Chevy engines need 16 bolt mains to stay together.

80_cutlass

What do you have right now? What sort of car is it in? How much ($$$$$) do you want to spend? What do you want to do with the car when you are finished?

These are all important questions.

sb

Warhead

X2 on what 80_Cutlass said.

Do not get hung up over a "number". Everyone says they make 400, 500, blah blah blah. 300 would scare them.

It takes 360 or so HP at the rear wheels with gears, and a 3500 converter, to run in the upper 11's. Most cars are not very streetable at that power level, unless they are on nitrous. Chevy, or not.

What do you want it to run-
How much can you afford?
Do you have another car to drive to work?

Jim

cutlassefi

You don't need 12.0:1 to get 400hp, especially with ported heads. And please balance it whether you're going to spin it 6000 or not.

I agree with Warhead and 80 Cutlass on most everything. Get a plan and budget and go from there. That might dictate alot.

Goofy

I was talking to performance shop about the olds engine to him what I wanted to get out of the 350, said about 6 G's what I was figuring it would cost. Doesn't sound like a problem to get that much power either

Goofy

This is a car that my dad bought new in 76, so I want to restore it and have some kick. All this car is to go out on a night cruse,some car shows and take it down the drag strip once in a while

80_cutlass

6 grand? Let's hear what sort of build that would be.

sb

Goofy

Can't do it for 6?

olds425

I think it may be possible to do it for less? Are they doing all the engine assembly?

72 cutlass455

What transmission and rear end is in it. These have a lot to do with giving it some kick. Seems to me for 6 grand the engine could be overhauled ported blueprinted have a new roller top end installed and a nos unit. A good posi unit with better gears would increase off the line kick.

Goofy

For 6 G's, she is ripped apart, punched out, flat or dome pistons, high cam with roller lifters, new Edlebrock aluminum heads and intake and carb, headers with dual exhaust and dynoed

Goofy

Stock trans and rear end, looks like will have to beef it up, what should I do with that

olds425

I think a good limited slip with upgraded axles would stand up to the power.

Warhead

For primarily a street runner without an overdrive transmission(Turbo 350), I would go for a 3.23-3.55 gear. Any more than that will kill your mileage, and cause the engine to run more rpm than you want at 60+miles per hour.

If you have an overdrive 2004R transmission, I would shoot for a 3.73-4.33 gear.

I would do the gear modifications before the engine swap, just to see what the improvement will be without anything else. You WILL be happy with the shot in the arm this will give.

Tuning will find far more power than you could believe.

You should be able to make that power number for a little more than half that cash wad.
$4500 max, with the gears, and posi installed.

JMO
Jim

80_cutlass

I guess Warhead and some others have beaten me to what I was alluding to in my original response about the $$$$.

Right off the bat I would ditch the edelbrock heads. There are better options if you just want to throw a wad of cash at heads for the small block in any case.

sb

71 Cutlass

Everything he said...I would just add that the car would probably not be streetable/street friendly at all if it was built to 400 HP.

Goofy

Why wouldn't you use edelbrock heads. What would you use????

70vert455

I am finding this all very interesting as I am wondering what to do with a motor. I have a very rare w-31 alum intake and the #6 1970 heads that many talk about. Bought 35 years ago and just hung onto them hoping to build an engine some day. Do I get a mid 70's 350 block and put them on it or a 403 or sell them and take the money and buy a 455?

Kyle's 77 Cutlass

I would keep them and use,I am a small block fan so i would keep them. Others will say different, that aluminium intake would be worth a bit.That it's self would be a gem on an engine.

dre

I've got a 72 350 rocket for sale if anyone is interested $200. This includes block, heads, alll pulleys, water pump, and a set of Edelbrock valve covers. Iv also got a set of 350 hoker heads for $100. No rust holes, just needs blasted and painted. Pm if you need pics

tonycpe

there you go, sounds like a good deal.

If I had 6 grand I would do the edelbrock head build that you mentioned. the heads would need the right amount milled to get the compression needed.
I think you would have more power than you might expect and would run pump gas.
Just my opinion
Also I have 1400 in my #5 heads , Sometimes I wish I would have just put that money towards a set of edelbrocks.

cutlassefi

Same here!

Oldwolf

X2 1400 here to, but it´s iron

Kyle's 77 Cutlass

Than what is better to use than the olds heads or edelbrock and what would last longer

80_cutlass

So, to use the E-brocks on a small block, I would have to use a proprietary intake, mill for combustion chamber size, and use an electric fuel pump.

No thanks, at least not for a build that can be accomplished with iron heads for less than the $$$ you guys have into your iron heads.

I still say save the ~$1200 bucks, put it toward your heads or some 6s or 5s or 7s and have money left over for upgrading the rear end.

sb

dre

By the way I forgot to mention it has 7a heads.

jag1886

The 350 Olds is the only engine I couldn't kill in my young/dumb years and I went through a lot of cars. I had a 68 Cutlass conv that I beat for about ten years and was still running when I sold it, I'd probably still have it if the body hadn't rusted to the ground.

Kyle's 77 Cutlass

Another silly question I have, lets say we have to 350's we build.Lets say for ****'s and giggle's we put the CR 10 to 1 on both engines. One engine we put #5 heads which is a 64cc chamber. On the other one we put #8 heads which have a 79 chamber. Port and polish and put the same size of valves in them. So my question is would there be a difference in performance between both engines