stock block power
02-06-2007, 05:38 PM
#1
3rd Gear Member
Thread Starter
Join Date: Sep 2006
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Posts: 892
stock block power
hey i was recently reading over an old post and it said the stock blocks on the 5.0s holds a max of 420 ponies. today i was reading the new 5.0 mustang mag and there is a fox in there i think a 93 that has stock block and has over 500 horses to the wheels. it also has a highrev cam so it makes power all the way to 6500 rpms. i was wondering if the stock block would hold this much. actually i was wondering if it would hold about 475. but i want to know if there isa catch or something you can do to strengthin the block
02-06-2007, 05:40 PM
#2
6th Gear Member
Join Date: Sep 2005
Location: Hamilton, NJ
Posts: 15,042
RE: stock block power
Everyone has mixed opinions about this and to be honest there is no one answer. There are people who have split them at 450 and there are people running over 600 rwhp with no problems. From what I hear I would consider anything past 450rwhp in the red zone. And it depends greatly on how high your spinning it.
02-06-2007, 07:49 PM
#8
2nd Gear Member
Join Date: Apr 2006
Posts: 335
RE: stock block power
well the stock block has been used reliably up to much more than 450 hp, but like we already said, others have cracked them with much less than that. There are essentially two reasons blocks crack... The first is vibrations, the second is twisting. anything you can do to eliminate those two things will help. You can put girdles in two places to help reduce twisting. A valley girdle can be used to strengthen the top of the block. Also, you can put a girdle over the main caps for the bottom end. Both of these parts are fairly cheap, but cost a lot to have thme installed due to how much that has to come apart to get to these areas. For vibrations, there aren't many things you can do, but keeping the rpms down and making sure you have good flexible motor mounts will help. The motor mounts bolt to pretty much the weakest areas of these blocks, so reducing vibrations here will help. Stay away from solid motor mounts. Also make sure your harmonic damper is good. There are upgrades for these also that help reduce vibrations in the motor.
Another thing to consider is the rest of the bottom end. Even if you buy all the parst I talked about and your block is really really strong, don't be surprised when that stock crank goes south, or a rod goes through the side of your strengthened block. Most people say that the crank is also only good to about 450 horse.
Another thing to consider is the rest of the bottom end. Even if you buy all the parst I talked about and your block is really really strong, don't be surprised when that stock crank goes south, or a rod goes through the side of your strengthened block. Most people say that the crank is also only good to about 450 horse.
02-07-2007, 10:28 AM
#10
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Join Date: Jan 2007
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Posts: 213
RE: stock block power
As has been said opinions vary, but heres mine. 1.)Never bore the cylinder more than .030" oversize. 2.) Install a main stud girdle with ARP bolts (the Trickflow girdle comes in a kit with ARP bolts washer, etc.). 3.)You'll need to have the blocks main bearing journals align honed, this is required when new main cap bolts are installed. 4.) Install a lifter valley girdle. 5.) Limit horsepower to 600 at the flywheelwith a 6500 rpm max redline. Thier are gonna be people that say they are or know someone making more power with the same set up and Ive seen it done myself, but it's been my experience that it considerably shortens the life of the block. Would you rather make 600 horsepower for many years or 800 horsepower for one or maybe two yearsdepending on how you drove it. Now ifthe enginesfora race car and you dont mind trading off longevity for more HP then pushing it to800 or even 900 HP might be the way to go.At that power level though,you'll need to fill the water jackets atleast halfway with some Blockfill to add even more strength to the block.