Chevy 350.
11-19-2003, 01:52 PM
#1
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Chevy 350.
Lets say I wanted to build a Chevy 350 with equlivelent longivity to the Porsche GTS engine. And power too.
So I can get the 345 hp easily enough from intake, heads, cams, exauste, and so forth.
What do I have to fix to make it hold up over time?
Lets see, NiCal coatings on the cylinders instead of nitrated cast iorn or steel.
Better valve stem seals.
The ignition and EFI is almost the same now, so no worrys there. The valve train has hydrolic lifters, probably roller, so no worrys there.
What else goes bye bye on a Chevy?
So I can get the 345 hp easily enough from intake, heads, cams, exauste, and so forth.
What do I have to fix to make it hold up over time?
Lets see, NiCal coatings on the cylinders instead of nitrated cast iorn or steel.
Better valve stem seals.
The ignition and EFI is almost the same now, so no worrys there. The valve train has hydrolic lifters, probably roller, so no worrys there.
What else goes bye bye on a Chevy?
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11-19-2003, 03:31 PM
#9
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I doubt you could do it, though fuel injection would be a requirement if you are going to come close. The bottom ends on 350s are plenty strong, even the two bolt mains.
I'm going to disagree with the lowering compression suggestion. Up to a point (say 10:1), more compression is a reliable way of adding power, more reliable than spinning the motor faster.
The real problem is the valvetrain, more specifically, the valvetrain mass. At 350 HP, you need a lot of airflow, which means both RPMs and lift. Unless you work on pulling mass out of the valvetrain, you will need lots of spring pressure, which is antithetical to long life. OHC engines have a huge advantage in this area...
I'm going to disagree with the lowering compression suggestion. Up to a point (say 10:1), more compression is a reliable way of adding power, more reliable than spinning the motor faster.
The real problem is the valvetrain, more specifically, the valvetrain mass. At 350 HP, you need a lot of airflow, which means both RPMs and lift. Unless you work on pulling mass out of the valvetrain, you will need lots of spring pressure, which is antithetical to long life. OHC engines have a huge advantage in this area...
11-19-2003, 03:39 PM
#10
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High quality parts cost money.
So if you want really durable pistons, crank, cams, lifters, etc, they will end up costing a lot of $$$.
The main appeal of a SBC, is that if it starts showing signs of age, you can pull the engine,
and drop in a new crate engine, or rebuild it completely, for very little money.
You don't have to use a specialty shop. Many people know how to rebuild them,
and many machine shops know them inside and out. It's really cheap to just
order another *new* crate engine, that is ready to run, for the price of a *used* 928 engine...
So if you want really durable pistons, crank, cams, lifters, etc, they will end up costing a lot of $$$.
The main appeal of a SBC, is that if it starts showing signs of age, you can pull the engine,
and drop in a new crate engine, or rebuild it completely, for very little money.
You don't have to use a specialty shop. Many people know how to rebuild them,
and many machine shops know them inside and out. It's really cheap to just
order another *new* crate engine, that is ready to run, for the price of a *used* 928 engine...
11-19-2003, 03:46 PM
#11
Burning Brakes
I'm not convinced that a small block chevy can be built to last as long as a 928 engine. You know what though, who cares? You can easily build it to run 400-450hp for 50-60k miles. Then you can throw it away and replace it with another for $5k. 50k miles is a long time for most of us and 5k is only a couple years worth of maint on a 928. Of course not all of that is engine related but a convincing case can be made
If you change up to the new design LS-1 smallblock, I bet you can easily crank out 400hp for 100-150k miles. That is what a stock Z06 runs.
Of course I didn't buy a Porsche to power it with a Chevy. In fact when I bought a muscle car I avoided Chevy's and bought a Buick. There is something cheap and simple about Chevy, everything else is a step up. That is where I want to be, a step up.
If you change up to the new design LS-1 smallblock, I bet you can easily crank out 400hp for 100-150k miles. That is what a stock Z06 runs.
Of course I didn't buy a Porsche to power it with a Chevy. In fact when I bought a muscle car I avoided Chevy's and bought a Buick. There is something cheap and simple about Chevy, everything else is a step up. That is where I want to be, a step up.
11-19-2003, 03:58 PM
#12
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When I say lower compression is more reliable im talking in the range of 10:1 or 11:1 compression. I have had hot rod motors with 12:1 and 13:1 with hot cams. That type of stuff makes the car idle rough. Its a fact that higher compression results in higher stress on rods, pistons, bearings, etc..
Thats why keeping it a lower compression motor, say under 11:1 will result in better daily driveablity and longer life. It also depends on your driving style as well.
And yes, headwork is very critical in producing good hp numbers. Go with the lightweight titanium stuff and a good set of aluminum heads. Roller cam and lifters are also good but add quite a bit of money over a standard cam and lifters.
Thats why keeping it a lower compression motor, say under 11:1 will result in better daily driveablity and longer life. It also depends on your driving style as well.
And yes, headwork is very critical in producing good hp numbers. Go with the lightweight titanium stuff and a good set of aluminum heads. Roller cam and lifters are also good but add quite a bit of money over a standard cam and lifters.
11-19-2003, 04:02 PM
#13
Administrator - "Tyson"
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Buy a stock LS6 and drop it in = 350bhp
I know a few C5 owners at 100K+ for miles with no issues.
Or, go for broke and order a C5-R crate motor.
I know a few C5 owners at 100K+ for miles with no issues.
Or, go for broke and order a C5-R crate motor.
11-19-2003, 04:33 PM
#15
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Buy a 405HP LS1 motor, lower the redline and tune it conservatively for 50 less HP or so and it'll last 200K miles easily. Alternatively get an LT1 and squeeze a few more HP out of it, or an LT4 and leave it more or less stock.
Weren't there some failures with the GTS engine? I always thought the S4 motor was the long-lived lump.
The SBC motor is pretty great, and really makes you wonder what the 928 motor would be like if it had lived as long and been developed as much. I liken the SBC to the old air-cooled 911 motor. Despite it's shortcomings it really makes a lot of power reliably.
Also consider that Chevy had the 32v LT5 and the Northstar family of OHC engines but still chose the pushrod motor for the Z06 'vette.
-Joel.
Weren't there some failures with the GTS engine? I always thought the S4 motor was the long-lived lump.
The SBC motor is pretty great, and really makes you wonder what the 928 motor would be like if it had lived as long and been developed as much. I liken the SBC to the old air-cooled 911 motor. Despite it's shortcomings it really makes a lot of power reliably.
Also consider that Chevy had the 32v LT5 and the Northstar family of OHC engines but still chose the pushrod motor for the Z06 'vette.
-Joel.