Iron Block 427 ? ?
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...

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.
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
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.
OR SHOULD I JUST FORGET THE 408... AND GET A LSX BLOCK.... OR MAYBE A BIG BLOCK?
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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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.
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
Nate
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...


