403 Olds or 400 sbc?

[G-Body_Vet]

Which would you pick for a cruiser if torque was your objective? I'm not considering big blocks because I want to keep the weight down. The car already has a SBC in it, but switching to Olds won't be a big deal. There's no exhaust on the car either so that's not a factor right now.

I have a good lead on both engines and some #7 Olds heads. I can get the 403 for $150 less though. I'd go with vortec heads if I got the 400. The car will be getting 3.73's and a 200-4R as well.

Let me hear some opinions and reasons. I'm more concerned with reliability than anything else. I've had plenty of Chevys but never owned an Olds for a long period of time.

 

[kornball426]

Big block olds should only weigh about 60 lbs more than a small block olds. It's not like SBC to BBC which is more like 120 lbs difference.

 

[G-Body_Vet]

I think the Olds 455 weighs around 605lbs. Is there an alternative A/C bracket that works with the g-body's radial compressor or is something going to have to be fabbed?

 

[Peter]

i love my sbo but honestly if you have the engine mounts for the chevy already, i would say go for the 400. the sbo will make more torque stock but i think picking between the sbc and sbo is just a matter of how unique you want to be.

 

[RockSS]

I am a HUGE chevy fan thru n thru but i can appreciate others, I am planning on 400 sbc for monte ss . That being said an olds 403 would be great and its tru stock it would have more torque but just the pure uniqueness of it all I'd go olds ...

 

[joe_padavano]

Big block olds should only weigh about 60 lbs more than a small block olds. It's not like SBC to BBC which is more like 120 lbs difference.

Just so we're all clear, a 403 is a SMALL BLOCK Olds. The 403 uses the same short deck height and 3.385" stroke as the 307 and 350 Olds motors. If the car came with a 307, the 403 is a bolt-in and has the added advantage that it's NOT a belly button SBC.

 

[stomis]

I'm not olds motor savvy on prices, availability etc. I can tell you for a fact that the 400sbc really should have an aftermarket rotating assembly in it because the short rods are just a bad idea for performance oriented engines whether theyre a cruiser or balls out racer.

The chevy parts are definitely going to be cheaper than the olds parts. Hell SBC parts are cheaper than any motor platform.

Heres somethings I would consider:

Are you looking for nostalgia or have any brand loyalty?

Make sure that 400 chevy block isnt bored over already.

Does mileage matter? Cause you'll get much better mileage with a q jet, and the olds motor.

 

[G-Body_Vet]

I'd really like to step up to an LSX engine, but with kids and impatience it's not gonna happen any time soon. Nostalgia isn't much of a factor. It's a Grand Prix with a sbc so it's already a b*st*rd car from the jump :lol:

I'm not much of a cookie-cutter guy either. I lean towards eccentricity or something different. I'm a huge fan of a properly running Q-Jet too. Mileage isn't a major concern but who doesn't like better mileage? I'd have to bump up the compression in either engine and would probably run premium depending on how far I went with the CR.

The appeal of a Chevy is part's prices, but maintenance on an Olds is a breeze. I almost like changing the plugs on them!
I had a Poncho 400 in a Regal before and I'd love to put that or a 455 in the GP, but there's more involved. Finding the right block, locating 301 mounts, heavy engine, good heads are expensive and the blocks are getting harder to come by.

In a nutshell, I guess I don't know what the hell I want to do! I'm really leaning towards Olds, possibly a 455 because I haven't really owned one. I know an Olds won't be as cheap as an sbc, but it won't break the bank either.

 

[stomis]

I'd really like to step up to an LSX engine, but with kids and impatience it's not gonna happen any time soon. Nostalgia isn't much of a factor. It's a Grand Prix with a sbc so it's already a b*st*rd car from the jump :lol:

I'm not much of a cookie-cutter guy either. I lean towards eccentricity or something different. I'm a huge fan of a properly running Q-Jet too. Mileage isn't a major concern but who doesn't like better mileage? I'd have to bump up the compression in either engine and would probably run premium depending on how far I went with the CR.

The appeal of a Chevy is part's prices, but maintenance on an Olds is a breeze. I almost like changing the plugs on them!
I had a Poncho 400 in a Regal before and I'd love to put that or a 455 in the GP, but there's more involved. Finding the right block, locating 301 mounts, heavy engine, good heads are expensive and the blocks are getting harder to come by.

In a nutshell, I guess I don't know what the hell I want to do! I'm really leaning towards Olds, possibly a 455 because I haven't really owned one. I know an Olds won't be as cheap as an sbc, but it won't break the bank either.

Excuse me while I sway you towards an LS series motor.

DO IT!

Get a carbd manifold and an MSD dizzy simulator until your read to tackle the fuel injection. Make two projects out of it and it wont seem like such a hill to climb.

LS1 core shortblocks go for as cheap as $500.

 

[83hurst-olds]

I'm not olds motor savvy on prices, availability etc. I can tell you for a fact that the 400sbc really should have an aftermarket rotating assembly in it because the short rods are just a bad idea for performance oriented engines whether theyre a cruiser or balls out racer.


Make sure that 400 chevy block isnt bored over already.

Those considerations should the reviewed for both engines in the subject line. I have had both and I dyno'd my 400 SBC at 425hp but never did my 403 so I am not sure they compare apples to apples. However, just my "seat of the pants" comparison is that the 403 is snappier but the 400 pulled harder and was faster overall. The 403 was just a street toy whereas the 400 for me was to pull my 20' boat (which it did VERY well for 6 years until the car was totalled out). I don't know if you have compared the prices for a 400 SBC to the Olds but they aren't off as far as you might think (especially if you compare them to the 305 or 350 SBC).