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Actuly truth be told any other division's engines were better than the pos chevy. Only morons lining their pockets in the board room think the piece of s#!+ no power no gas milage chevy engine was ok. Now back to topic at hand;
The 403 in completely stock form wasn't much on power (but still spanked the chevy engines of the day). But replace the stock no duration no lift cam with even a stock cam from the late 60's, 3 angle valve job, early pre-egr intake, and it made great power. I've made ver 550 hp with a 403 and yes, it lived. I've never heard of the 403 having any overheating issues in normal applications. You do not want to ever add nitrous to one though. That will takeout the open webbed mains. The 4.350" bore was a great way to go up from the 350's size but still use the same 350 crank casting. FCR (I believe they are in Omaha, NE possibly) has built even more power from the 403, but I am noyt sure short of welding in supports for the main webbing what they did to the block.
Only morons lining their pockets in the board room think the piece of s#!+ no power no gas milage chevy engine was ok.
To Quote Larry the Cable Guy, " now that's funny, I don't care who you are"
Is there any engine you haven't built and made over 550hp or more with?
In the mid-80's, I was in charge of a fleet of 455" Olds engines used in industrial applications. They ran huge water pumps out in the field, and ran 24/7/365, under a very heavy load. They were hooked to a natural gas pipe, so they never needed fueling.
Oldsmobile gave me a couple of these engines to try and see how they would work for that application. I could duplicate, in a few months, the use an engine would get in automotive use in a few years., so they used me for a test bed.
They couldn't begin to replace the 455 for Industrial use. As soon as they wore out, we dumped them.
They might fair better for hi-performance use, but I would have my doubts...
I'm not surprised. That Olds 455 was a pretty ballsy engine.
Actuly truth be told any other division's engines were better than the pos chevy. Only morons lining their pockets in the board room think the piece of s#!+ no power no gas milage chevy engine was ok. Now back to topic at hand;
The 403 in completely stock form wasn't much on power (but still spanked the chevy engines of the day). But replace the stock no duration no lift cam with even a stock cam from the late 60's, 3 angle valve job, early pre-egr intake, and it made great power. I've made ver 550 hp with a 403 and yes, it lived. I've never heard of the 403 having any overheating issues in normal applications. You do not want to ever add nitrous to one though. That will takeout the open webbed mains. The 4.350" bore was a great way to go up from the 350's size but still use the same 350 crank casting. FCR (I believe they are in Omaha, NE possibly) has built even more power from the 403, but I am noyt sure short of welding in supports for the main webbing what they did to the block.
The design does have some limitations due to the siamesed cylinders and windowed webs. You must insure the cooling system is large enough and in good order. I would not recommend one for an ultimate dragstrip build up, and I would avoid doing anything that greatly raised the compression especially if the block was overbored. Head gaskets blowing would be the concern here.
Big pistons and a short stroke are an excellent combination for a high-RPM engine, but here the other inherent 403 weakness comes into play: Windowed main webs, and to a lesser extent, siamesed cylinders. The bottom end of this block is not suitable for extended use at high rpm with very high cylinder pressure.
Getting back to the original question, unless somebody gave you a 403, if you want a big-cube small block, I think you get a 377 by putting a 350 crank in a 400 SBC block, this gives pretty big displacement with a shorter stroke, you can put whatever heads, cam, intake, and exhaust on that you want/can afford...
Not sure what was going on with that weak, hollowed out bottom end on the 403. Probably a cost-saving measure, GM is infamous for cutting corners like that.
Posted by GTOLOVER;
The design does have some limitations due to the siamesed cylinders and windowed webs. You must insure the cooling system is large enough and in good order. I would not recommend one for an ultimate dragstrip build up, and I would avoid doing anything that greatly raised the compression especially if the block was overbored. Head gaskets blowing would be the concern here.
The head gaskets are not a concern because of deck design is better. The siamesed cylinder blocks are the ones you want to build on. They are stronger than non siamesed cylinder blocks. A running engine has many torisional twists, harmonic "waves" both front to rear and side to side, even in a diagonal cross pattern. The siamesed blocks regardless of brand will always hold up better and actuly make more power. I've seen a freshed up rotating asembly changed from a non siamesed block to an aftermarket siamesed block and gain 35 hp. some of it was no doubt the new rings, but the rest I am sure was due to the better block. I too would not go over 11.5 to 1 compression, and if on pump gas, thne 10.5 to 1 compression max with alum. heads. Iron heads I'd drop it down to 9.5 to 1.
The strongest small block you are going to build with factory blocks is the Olds Diesel block combo with the forged 425 crank in it with the rod journals turned down to a large journal sbc dia. This also allows you to give some extra stroke when turning the crank. Use the Rocket Racing heads on it, or bullydogs, and you'll enjoy smoking the stroker sbc's. I've built serveral 434"-440" combo's using the diesel block. Toughest mass production line block you'll ever get. If you get one of the siamesed diesel blocks, all the better. 4.390" bore capible with a 4.100 stroke, in a short deck combo, it'll be quick. Now if we get the time and chance to develope the CV head for the Olds engine........
Getting back to the original question, unless somebody gave you a 403, if you want a big-cube small block, I think you get a 377 by putting a 350 crank in a 400 SBC block, this gives pretty big displacement with a shorter stroke, you can put whatever heads, cam, intake, and exhaust on that you want/can afford...
Not sure what was going on with that weak, hollowed out bottom end on the 403. Probably a cost-saving measure, GM is infamous for cutting corners like that.
To me, it is a waste of time and money to build a stroker sbc when you can start with a 400 sbc. Cost vs what you get powerwise in return in sbc's, nothing beats the 400sbc. Now if you want a 400 cube Olds engine, there are serveral options including the factory 400's, and 403's.
Actuly truth be told any other division's engines were better than the pos chevy. Only morons lining their pockets in the board room think the piece of s#!+ no power no gas milage chevy engine was ok.
Some people never learn. Must have a bad taste left in your mouth after getting beat by one too many Chevy engines, otherwise why all the hate?
Some people never learn. Must have a bad taste left in your mouth after getting beat by one too many Chevy engines, otherwise why all the hate?
Why the hate for the most over rated engine ever built? I've built and raced plenty of them. I've even set a couple class records with them, but they are still the biggest pos over rated engine to ever be stuck under the hood. Funny thing is everything I ever did with the sbc, I ran even quicker with other brand engines!
Now let's get back to the topic of this thread; the better than a sbc 403 Olds engine.
Why the hate for the most over rated engine ever built? I've built and raced plenty of them. I've even set a couple class records with them, but they are still the biggest pos over rated engine to ever be stuck under the hood. Funny thing is everything I ever did with the sbc, I ran even quicker with other brand engines!
Because the other brand engines were set up more for low rpm torque from the factory which is what moves you...most sbcs with the exception of maybe the 400 were not all that torquey from the factory. Of course I keep seeing you mention 305's in your posts so it comes as no surprise why you wonder why an economy engine isn't a performer. Overrated? Maybe but the SBC is far from a pos otherwise no one would be building them.
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Use the Rocket Racing heads on it, or bullydogs, and you'll enjoy smoking the stroker sbc's. I've built serveral 434"-440" combo's using the diesel block. Toughest mass production line block you'll ever get.
If you get one of the siamesed diesel blocks, all the better. 4.390" bore capible with a 4.100 stroke, in a short deck combo, it'll be quick. Now if we get the time and chance to develope the CV head for the Olds engine........
Some people never learn. Must have a bad taste left in your mouth after getting beat by one too many Chevy engines, otherwise why all the hate? 
