427 engines, etc.
#1
10-14-2006, 04:26 PM
Join Date: Jul 2005
Location: Central North Carolina
Posts: 2,105
427 engines, etc.
The Mallet thread elsewhere and a couple of other threads have all discussed upgraded engines, particularly 427s. I thought I would share my experience.
427 cubic inch engines
There is nothing special about 427 cubic inches except: it is exactly seven liters, and the first 427s, back in the mid 60s, were among the most legendary Chevy engines.
There are three different 427s for Corvettes, depending on the vintage:
1) The original big-block from 1966 that was available as 396, 427, or 454 cubic inches in various versions. Sometimes called the Porcupine (for that way the valve stems poked up in different angles under the rocker covers) or the "Rat" (as opposed to the small-block “Mouse.” All but a very rare few were iron block, many had iron heads although many had aluminum heads – big wide and heavy engines, but strong. All stock engines were carbureted.
These fit in C3s and most 60s and 70s Camaros, Novas, etc. Certain crate engine versions of it are available up to 572-630 cubes cubic inches. With enough money you can do anything, but non one would really want to put one of these in a C4, C5, or C6 – too big, too heavy, no advantage over newer engines.
2) Small block 427s. This was never offered by Chevy, but there are 427 cubic inch crate engines available that are stroked and bored versions of small block (LT-vintage engines. Most are carbureted engines although I imagine you could rig up fuel injection. They will fit in C2 through C4 cars (might fit C1s, I expect): a not too expensive way to get big block cubes into a small block car. Lots of torque, but not for serious racing – the small block is just too weak for racing that many cubes.
3) C5R and LS7.
C5R (Corvette 5th-generation, Racing). The only way you could or can get one of these is to buy the C5R block from GMHP division, then build the engine yourself with aftermarket parts. The GM "C5R" block comes from the factory labeled "LS1- 7 liters" and is essentially hand-cast with steel liners for a true 4 inch bore and stronger webbing around the crankshaft bearings than a stock LS1, 2, or 6 engine, but otherwise had the same dimensions (everything from an LS1 would fit, heads, oil pumps, etc.)
C5R engines, as either crate or complete and installed, were available from about 1999 on from various tuners like Lingenfelter, MTI, Mallet, etc. The most “original” you could buy was from Katech -- they built the C5R race engines for GM's Lemanss team, as well as other weird LS engines (the doubled, 12-liter LS1 “V16” in a show Cadillac, etc.).
By the time a C5R engine was in the car and everything correct and ready to go, total cost from a good tuner was about $24,000 - $28,000 depending on the quality of the aftermarket crankshaft, rods, pistons, etc. Normally aspirated RWHP was right around 500, or, with an aggresive cam and tune, the type that gives a rough idle, up to 535.
The LS7 is essentially a production version of the C5R, and is the engine in the C6 ZO6. One big difference with the C5R: most C5Rs on the street have a wet sump (oil pan and filter like other LS engines), although the actual racing C5R, and the LS7, use a dry sump (oil is contained in a tank to the side of the engine).
LS7 crate engines are now available for around $13k now -- I imagine someone is offering stock LS7s retro-fitted into C5s or C4s from about $20K total, but I don’t know details. The LS7 puts out about 450 RWHP stock and with headers and cam, about 500 to 550. It can do slightly better than a wet-sump C5R if pushed hard because the dry sump gains it about 15 HP.
Some important points for anyone who is going to go with a C5R or LS7: the stock LS7 is a good strong engine but not bulletproof – if you plan on increasing it much past 575 RWHP do not use the stock bottom end -- spend money on super-grade aftermarket crank, pistons, and rods. And don’t forget the upper end (valves, rockers, etc.) – if the LS7 has a weakness, it is weak there.
With either engine, one strong recommendation: replace the stock radiator with a dual core one – the bigger engine needs more cooling. Install an engine oil cooler. Upgrade to a replaceable element oil filter. Tub the rear wheel wells and get serious rubber on the rear: 12 or 13 inch wide wheels with 335 or winder tires: I run 13 inch wide Fikse's with 345 wide drag radials – max traction but they only last 5000 miles per set.
Supercharging or putting turbos on a C5R or LS7 427 is the route of choice for all the tuners when they want big HP numbers. Most tuners offer C5R or LS7 based engines with mild boost (5-6 lbs) and a claimed 650 or so HP (575 RW) for around $50K (that includes the C5R or LS7 engine). For more money they will run the boost and the power on up, the additional money pays for stronger internals, drive-train, and more cooling, etc.: more than 900 at the RW is possible – it’s just money.
These most powerful ‘vettes are famous for shreadding the rear differential – it tends to wear out quickly, or just explode if the clutch is dropped with too much power.
I believe the ‘vette chassis can really handle only about 650 HP at the rear wheels, although next month my shop will try to coax 700 RWHP out of mine. 600+ HP is a lot of power to put through just two tires, no matter how big: more than that really needs 4-wheel drive, in my opinion.
I have not driven mine with more than 603 RWHP. That amount of power is scary. It can only be applied in a straight line and then carefully. First gear is nothing but wheelspin and fishtailing, no matter how you try to feather the clutch: flooring the throttle at any RPM just snaps the rear tires loose. Second gear is not much better and the car will occasionally break the tires loose as it nears the torque peak in 3rd.
One automotive dream, among many I have is to eventually have three generations of Chevy 427, a 68 or 69 427 C3, a C4 around a '94, with a 427 small block, and my present C5 with a 427 LS engine. Where I would keep them, I have no idea, but it would be fun.
427 cubic inch engines
There is nothing special about 427 cubic inches except: it is exactly seven liters, and the first 427s, back in the mid 60s, were among the most legendary Chevy engines.
There are three different 427s for Corvettes, depending on the vintage:
1) The original big-block from 1966 that was available as 396, 427, or 454 cubic inches in various versions. Sometimes called the Porcupine (for that way the valve stems poked up in different angles under the rocker covers) or the "Rat" (as opposed to the small-block “Mouse.” All but a very rare few were iron block, many had iron heads although many had aluminum heads – big wide and heavy engines, but strong. All stock engines were carbureted.
These fit in C3s and most 60s and 70s Camaros, Novas, etc. Certain crate engine versions of it are available up to 572-630 cubes cubic inches. With enough money you can do anything, but non one would really want to put one of these in a C4, C5, or C6 – too big, too heavy, no advantage over newer engines.
2) Small block 427s. This was never offered by Chevy, but there are 427 cubic inch crate engines available that are stroked and bored versions of small block (LT-vintage engines. Most are carbureted engines although I imagine you could rig up fuel injection. They will fit in C2 through C4 cars (might fit C1s, I expect): a not too expensive way to get big block cubes into a small block car. Lots of torque, but not for serious racing – the small block is just too weak for racing that many cubes.
3) C5R and LS7.
C5R (Corvette 5th-generation, Racing). The only way you could or can get one of these is to buy the C5R block from GMHP division, then build the engine yourself with aftermarket parts. The GM "C5R" block comes from the factory labeled "LS1- 7 liters" and is essentially hand-cast with steel liners for a true 4 inch bore and stronger webbing around the crankshaft bearings than a stock LS1, 2, or 6 engine, but otherwise had the same dimensions (everything from an LS1 would fit, heads, oil pumps, etc.)
C5R engines, as either crate or complete and installed, were available from about 1999 on from various tuners like Lingenfelter, MTI, Mallet, etc. The most “original” you could buy was from Katech -- they built the C5R race engines for GM's Lemanss team, as well as other weird LS engines (the doubled, 12-liter LS1 “V16” in a show Cadillac, etc.).
By the time a C5R engine was in the car and everything correct and ready to go, total cost from a good tuner was about $24,000 - $28,000 depending on the quality of the aftermarket crankshaft, rods, pistons, etc. Normally aspirated RWHP was right around 500, or, with an aggresive cam and tune, the type that gives a rough idle, up to 535.
The LS7 is essentially a production version of the C5R, and is the engine in the C6 ZO6. One big difference with the C5R: most C5Rs on the street have a wet sump (oil pan and filter like other LS engines), although the actual racing C5R, and the LS7, use a dry sump (oil is contained in a tank to the side of the engine).
LS7 crate engines are now available for around $13k now -- I imagine someone is offering stock LS7s retro-fitted into C5s or C4s from about $20K total, but I don’t know details. The LS7 puts out about 450 RWHP stock and with headers and cam, about 500 to 550. It can do slightly better than a wet-sump C5R if pushed hard because the dry sump gains it about 15 HP.
Some important points for anyone who is going to go with a C5R or LS7: the stock LS7 is a good strong engine but not bulletproof – if you plan on increasing it much past 575 RWHP do not use the stock bottom end -- spend money on super-grade aftermarket crank, pistons, and rods. And don’t forget the upper end (valves, rockers, etc.) – if the LS7 has a weakness, it is weak there.
With either engine, one strong recommendation: replace the stock radiator with a dual core one – the bigger engine needs more cooling. Install an engine oil cooler. Upgrade to a replaceable element oil filter. Tub the rear wheel wells and get serious rubber on the rear: 12 or 13 inch wide wheels with 335 or winder tires: I run 13 inch wide Fikse's with 345 wide drag radials – max traction but they only last 5000 miles per set.
Supercharging or putting turbos on a C5R or LS7 427 is the route of choice for all the tuners when they want big HP numbers. Most tuners offer C5R or LS7 based engines with mild boost (5-6 lbs) and a claimed 650 or so HP (575 RW) for around $50K (that includes the C5R or LS7 engine). For more money they will run the boost and the power on up, the additional money pays for stronger internals, drive-train, and more cooling, etc.: more than 900 at the RW is possible – it’s just money.
These most powerful ‘vettes are famous for shreadding the rear differential – it tends to wear out quickly, or just explode if the clutch is dropped with too much power.
I believe the ‘vette chassis can really handle only about 650 HP at the rear wheels, although next month my shop will try to coax 700 RWHP out of mine. 600+ HP is a lot of power to put through just two tires, no matter how big: more than that really needs 4-wheel drive, in my opinion.
I have not driven mine with more than 603 RWHP. That amount of power is scary. It can only be applied in a straight line and then carefully. First gear is nothing but wheelspin and fishtailing, no matter how you try to feather the clutch: flooring the throttle at any RPM just snaps the rear tires loose. Second gear is not much better and the car will occasionally break the tires loose as it nears the torque peak in 3rd.
One automotive dream, among many I have is to eventually have three generations of Chevy 427, a 68 or 69 427 C3, a C4 around a '94, with a 427 small block, and my present C5 with a 427 LS engine. Where I would keep them, I have no idea, but it would be fun.
#3
10-15-2006, 11:57 AM
RE: 427 engines, etc.
And my dream is to put an LS7 into my C3.
Something tells me that 510 ft-lbs of torque might just cause a little havoc between the trans and the wheels. 
http://www.turnkeyenginesupply.com/street_70540.htm
At $18,900, the wife won't let me dream about it too much, but the $6,300 for an LQ9 might fit the "toy cars" budget a little better. Of course, I would put the LS1 style covers on it to make it at least look scary vette-ish.
http://www.turnkeyenginesupply.com/street_60390.htm
bill.
#4
10-15-2006, 01:47 PM
Join Date: Jul 2005
Location: Central North Carolina
Posts: 2,105
RE: 427 engines, etc.
Dressed up with lots of chrome, the LQ9 would look quite good in its own right, and very correct for a C3.
#5
10-15-2006, 08:15 PM
RE: 427 engines, etc.
Does that mean that you'll help convince my wife that this is not a wish, but belongs on the "absolutely must have or the earth will stop rotating" list?
Turnkey switched websites recently, but their gallery used to have some great shots of peoples' "dressing" of their engines. They make injector rail covers that look alot like stock valve covers, so basically the LS1/LS6/LQ9 end up looking like a ram-air 350. They have color matched covers (kinda Foose-ish), carbon fibre, chrome, in all shapes and degrees of "hiding what's underneath".I'm in lust with this idea... An LQ9, a modern trans with overdrive... talk about a sleeper to race to the next redlight with the ricer boys.
bill.
#6
10-15-2006, 10:23 PM
RE: 427 engines, etc.
Hey guys, figured I might post a site up here that I found while looking through a Chevy Performance magazine. The site is www.speedomotive.com . From what I can see, they look like a safe site to buy from. Most of the motors they offer come with a Turn Key Dyno Tested option and the prices look very reasonable to me. Anyway, just figured I would throw that in there. Some day, I hope to buy a 454 and put it in a 69 Camaro. But I have to rob a few banks first. 
Matt
Matt
#7
10-17-2006, 01:37 PM
RE: 427 engines, etc.
ORIGINAL: Lee Willis
One automotive dream, among many I have is to eventually have three generations of Chevy 427, a 68 or 69 427 C3, a C4 around a '94, with a 427 small block, and my present C5 with a 427 LS engine. Where I would keep them, I have no idea,....
One automotive dream, among many I have is to eventually have three generations of Chevy 427, a 68 or 69 427 C3, a C4 around a '94, with a 427 small block, and my present C5 with a 427 LS engine. Where I would keep them, I have no idea,....
#8
10-17-2006, 03:28 PM
RE: 427 engines, etc.
Hi Lee Willis, great post! I was at a Vette show in early spiring and on both sides of me were two 427's with just headers. They each cranked up there cars to show who had the best sound, they nearly vebrated the buildings down. Theres nothing like the sound of a killer big block.PG
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