Iron Block 427 ? ?
10-03-2008, 06:22 PM
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Iron Block 427 ? ? 2004 CHEVY 1/2 TRUCK
I HAVE A 6.0 BLOCK THAT I HAVE TURNED INTO A FORGED 408 CI IT WAS A GOOD RUNING MOTOR .... BUT I NEED MORE
NOW HERE IS WHAT I M THINKING ABOUT DOING...
BOREING IT 4.125 AND MAKEING IT A 427 N/A MOTOR
I WILL HAVE PAT G SPEC. ME A CAM
MAYBE USE MY AFR 225/65 NOT SHURE IF THAT WILL WORK OR NOT ??
FAST 90/90
42LBS INJECTORS WITH STOCK FUEL PUMP
DOES THIS SOND LIKE A GOOD COMBO ? I WILL BE RUNNING THIS TRUCK ON THE ROAD.. AND GOOD CHANCE I WILL PUT NOS TO IT...
I DONT WANT IT OVER HEATING AND GIVEING ALOT OF PROBLEMS...
10-03-2008, 07:02 PM
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You cant punch an Fe block out that far. The most I've ever seen is 4.060 with a sonic test. The only way to get that CI out of that block is to get a 4.125" crank.
10-03-2008, 07:17 PM
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a 4.060 bore with a 4.125 crank is a 427.
Have you thought of building an LS7 blocked motor? You would be able to keep pretty much everything except for the pistons. You would also loose a good bit of weight. When everything is all said and done you would be close in price vs trying to make the Fe block a 427.
Have you thought of building an LS7 blocked motor? You would be able to keep pretty much everything except for the pistons. You would also loose a good bit of weight. When everything is all said and done you would be close in price vs trying to make the Fe block a 427.
10-03-2008, 07:27 PM
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In my opinion, 408 is about the safe limit for an iron block. I also think that going to 427 CID will not really gain you very much in terms of performance over a 408 with the weight of a truck.
If you want bigger cubes, I'd do something like get an LSX block and bore it as desired. Buy appropriate pistons and reuse your crank, rods and other pieces (including your heads and cam). Then see where you are. I had my block sonic checked before it was bored to 4.030" and that's all it can be safely bored.
I researched this topic in detail a couple of years ago and found that most LQ4/9 blocks won't go beyond 4.030". A handful, perhaps 5%, are suitable to be bored to 4.060"
Steve
If you want bigger cubes, I'd do something like get an LSX block and bore it as desired. Buy appropriate pistons and reuse your crank, rods and other pieces (including your heads and cam). Then see where you are. I had my block sonic checked before it was bored to 4.030" and that's all it can be safely bored.
I researched this topic in detail a couple of years ago and found that most LQ4/9 blocks won't go beyond 4.030". A handful, perhaps 5%, are suitable to be bored to 4.060"
Steve
10-03-2008, 07:30 PM
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THAT WOULD BE BAD ***... THATS A GOOD IDEA BUT ... I THINK MY CRANK HAS 24X RELUCTOR RING AND I THINK THE CRANK SENOSOR IS DIFF. SPOT ON THE BLOCK... ?
a 4.060 bore with a 4.125 crank is a 427.
Have you thought of building an LS7 blocked motor? You would be able to keep pretty much everything except for the pistons. You would also loose a good bit of weight. When everything is all said and done you would be close in price vs trying to make the Fe block a 427.
Have you thought of building an LS7 blocked motor? You would be able to keep pretty much everything except for the pistons. You would also loose a good bit of weight. When everything is all said and done you would be close in price vs trying to make the Fe block a 427.
10-03-2008, 07:38 PM
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IN YOUR OPINION WITH MY HEAVY TRUCK.. WOULD I BE BETTER TO TAKE MY 408 AND TURBO OR SUPERCHARGER IT TO GET MORE POWER OUT IF HER?
OR SHOULD I JUST FORGET THE 408... AND GET A LSX BLOCK.... OR MAYBE A BIG BLOCK?
OR SHOULD I JUST FORGET THE 408... AND GET A LSX BLOCK.... OR MAYBE A BIG BLOCK?
In my opinion, 408 is about the safe limit for an iron block. I also think that going to 427 CID will not really gain you very much in terms of performance over a 408 with the weight of a truck.
If you want bigger cubes, I'd do something like get an LSX block and bore it as desired. Buy appropriate pistons and reuse your crank, rods and other pieces (including your heads and cam). Then see where you are. I had my block sonic checked before it was bored to 4.030" and that's all it can be safely bored.
I researched this topic in detail a couple of years ago and found that most LQ4/9 blocks won't go beyond 4.030". A handful, perhaps 5%, are suitable to be bored to 4.060"
Steve
If you want bigger cubes, I'd do something like get an LSX block and bore it as desired. Buy appropriate pistons and reuse your crank, rods and other pieces (including your heads and cam). Then see where you are. I had my block sonic checked before it was bored to 4.030" and that's all it can be safely bored.
I researched this topic in detail a couple of years ago and found that most LQ4/9 blocks won't go beyond 4.030". A handful, perhaps 5%, are suitable to be bored to 4.060"
Steve
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10-03-2008, 07:49 PM
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I had an iron block LQ4 that was sonic tested and bored out to 4.115 with and 4.000 crank it was a 426 ci.. never had a problem with it and its still running to this day
10-04-2008, 12:52 AM
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redchevytruck,
I'd probably supercharge it with a RADIX if I wanted more performance. Notice that I didn't say power. If you have a heavy vehicle, torque is your biggest friend, not HP.
If you want to stay NA, you probably have over-cammed your truck currently (too much duration) and it may be a dog until about 3,500 RPMs. If so, something like the Comp 54-451-11 cam (208/212 @ .050") but on about a 112 LSA might be a good starting place.
I'd probably supercharge it with a RADIX if I wanted more performance. Notice that I didn't say power. If you have a heavy vehicle, torque is your biggest friend, not HP.
If you want to stay NA, you probably have over-cammed your truck currently (too much duration) and it may be a dog until about 3,500 RPMs. If so, something like the Comp 54-451-11 cam (208/212 @ .050") but on about a 112 LSA might be a good starting place.
10-04-2008, 12:54 AM
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CougarL92,
What were the results of your sonic test. Do you have the test sheet? I have to think that you have some really thin spots on your cylinder walls at 4.115" bore.
Steve
What were the results of your sonic test. Do you have the test sheet? I have to think that you have some really thin spots on your cylinder walls at 4.115" bore.
Steve
10-04-2008, 06:56 AM
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I second the over cammed part, especially considering the cams that a lot of people are using for the heavier GTO, you just can't run an F-body cam with that heavy body. I have a 220/224 with a 110+1 lsa and it never runs out of TQ, still pulls hard up to 6000. You might really consider an LSX block as that would give you all sorts of possibilities including massive boost if you ever want to go FI in the future
Nate
Nate
10-04-2008, 08:47 AM
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If its a 408 you step up to a 421 thats only 13 ci. if you figure 1 hp per ci that 13 hp yank yank. even if it were 2 hp per ci yank. stick with the 408. It is more reliable as far as piston rock goes.
10-04-2008, 08:59 AM
#13
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YA I KNOW TQ IS WHERE ITS AT WITH MY TRUCK.... SO MAYBE IF I WENT TO A LOWER COMPRESSION (9 TO 1)? AND A Magna Charger ~ WOULD THE 5 GRAND I SPEND BE WORTH THE GANE ?
AND BEFOR I PUT IT BACK TOGETHER WITH WHAT EVER COBO I GO WITH I M GOING TO HAVE PATRICK G SPEC. ME A CAM FOR MY COBO SO I CAN GET THE MOST OUT OF IT...
AND BEFOR I PUT IT BACK TOGETHER WITH WHAT EVER COBO I GO WITH I M GOING TO HAVE PATRICK G SPEC. ME A CAM FOR MY COBO SO I CAN GET THE MOST OUT OF IT...
