302 crack ing

engine_kid · 10-17-2007

i have heard a lot about the 302 blocks start to split or crack when you get up around the 600 hp range. does anybody know why they do this and is it really that bad or just some of the full out racing engines doing this. Just wondering im a little bored and im planning on building a 347 strocker in the somewhat close future.

svtsilversnake · 10-17-2007

my buddy has a 302 thats blown with 21 lbs of boost and 650 hp. but he doesnt have that many miles on it though

Gtconv91 · 10-17-2007

i also imagine that there is some RPM involved in that as well..

Intmdtr · 10-18-2007

whats causing them to split or crack is the added torque the engine is producing. i have seen my old 302 pull the head studs right out of the block i also cracked a block...mind you those were 2 older motors

jsam · 10-18-2007

they are not beefy enough in the lifter galley to handle that kind of hp for a long period of time.

engine_kid · 10-18-2007

does this happen more when you are in the higher rpm's or will it happen over time? im plannig on building a 347 with around 500hp maybe well see what happens.

Jasperstang308 · 10-20-2007

550 is about the max. the blocks were just poorly made hence the need for aftermarket blocks. revs also kill the motor. try to keep the revs at a max of 6500 if you want the block to last. Also get main studs, deburr the block, and get a main girdle to help with main stability.

91gt347 · 10-22-2007

Quote:

Originally Posted by Jasperstang308

550 is about the max. the blocks were just poorly made hence the need for aftermarket blocks. revs also kill the motor. try to keep the revs at a max of 6500 if you want the block to last. Also get main studs, deburr the block, and get a main girdle to help with main stability.

I agree with him. From my experience its luck of the draw. One will break at 500,the next will hold 650 for a long time. I just gave(Yes I said gave) a stock block 331 to my dad. He's running mid 9's on a 175 shot. IMO tuning is one big key to survival too.

Jasperstang308 · 10-24-2007

tuning is a BIG PART of it that and the machine work. there is a guy on another forum i hang out on is making i think it was 650 to the wheels with a F.A.S.T system

engine_kid · 10-24-2007

damn thats sweet. i think mine is going to be carb'd but im going to put main girdle and valley girdles in to help strenghten the block a little. and studs on everything.

10-17-2007	#1 (permalink)
engine_kid engines turn me on Join Date: May 2007 Location: Grand Haven, MI Posts: 49 iTrader: (0) Friends: (0) Last Online: 10-29-2008 02:03 PM Time Spent Online: 4 Minutes 7 Seconds My Album's: engine_kid's album Thanks: 0 Thanked 0 Times in 0 Posts	302 crack ing i have heard a lot about the 302 blocks start to split or crack when you get up around the 600 hp range. does anybody know why they do this and is it really that bad or just some of the full out racing engines doing this. Just wondering im a little bored and im planning on building a 347 strocker in the somewhat close future. __________________ 94 chevy pickup 4.3L 5 spd. but building a 400-450 hp 355. Next project is a 347 stroker or 496 BBC not sure. But then a mustang for the 347 or 67 chevy pickup for the 496.

10-17-2007	#3 (permalink)
Gtconv91 I need a Beer Join Date: Aug 2006 Location: Cheyenne, Wy Posts: 2,644 iTrader: (2) Friends: (4) Last Online: 1 Day Ago 03:23 PM Time Spent Online: 1 Day 23 Hours 58 Minutes 30 Seconds My Album's: Gtconv91's album My Garage: Gtconv91's Garage Thanks: 0 Thanked 1 Time in 1 Post	i also imagine that there is some RPM involved in that as well.. __________________ slow.......... 12.30 @ 110 91 Gt conv

10-18-2007	#4 (permalink)
Intmdtr Leader of Men Real Name: Brian Join Date: May 2007 Location: Wasaga Beach, Ontario Posts: 9,312 iTrader: (1) Friends: (34) Last Online: 9 Hours Ago 04:59 PM Time Spent Online: 2 Weeks 5 Days 21 Minutes 54 Seconds My Album's: Intmdtr's album My Garage: Intmdtr's Garage Thanks: 1 Thanked 29 Times in 28 Posts	whats causing them to split or crack is the added torque the engine is producing. i have seen my old 302 pull the head studs right out of the block i also cracked a block...mind you those were 2 older motors __________________ HELLO My Name is BRIAN "Without Warning, Without Conscience" *"Live life to the fullest, it's not a dress rehearsal"*

10-18-2007	#5 (permalink)
jsam 2v hater Real Name: jonathan Join Date: Jan 2007 Location: frankiln ky Posts: 1,043 iTrader: (0) Friends: (3) Last Online: 17 Hours Ago 09:05 AM Time Spent Online: 3 Days 59 Minutes 16 Seconds My Album's: jsam's album My Garage: jsam's Garage Thanks: 1 Thanked 1 Time in 1 Post	they are not beefy enough in the lifter galley to handle that kind of hp for a long period of time. __________________ 85 gt 347 stroker. pa aod. it's a f'n money pit 79 cobra 302 4 spd 36k original miles 68 coupe, 93 calypso hatch www.bowlinggreenmustangs.com

10-20-2007	#7 (permalink)
Jasperstang308 Gold Member Join Date: Apr 2007 Posts: 189 iTrader: (0) Friends: (1) Last Online: 09-16-2011 01:56 AM Time Spent Online: 3 Hours 41 Minutes 29 Seconds My Album's: Jasperstang308's album Thanks: 0 Thanked 0 Times in 0 Posts	550 is about the max. the blocks were just poorly made hence the need for aftermarket blocks. revs also kill the motor. try to keep the revs at a max of 6500 if you want the block to last. Also get main studs, deburr the block, and get a main girdle to help with main stability. __________________ doing a lot with a little

10-17-2007	#2 (permalink)
svtsilversnake go baby go Join Date: May 2007 Location: springdale, arkansas Posts: 782 iTrader: (1) Friends: (5) Last Online: 04-08-2009 09:00 PM Time Spent Online: 2 Hours 24 Minutes 7 Seconds My Album's: svtsilversnake's album My Garage: svtsilversnake's Garage Thanks: 0 Thanked 0 Times in 0 Posts	my buddy has a 302 thats blown with 21 lbs of boost and 650 hp. but he doesnt have that many miles on it though

10-18-2007	#6 (permalink)
engine_kid engines turn me on Join Date: May 2007 Location: Grand Haven, MI Posts: 49 iTrader: (0) Friends: (0) Last Online: 10-29-2008 02:03 PM Time Spent Online: 4 Minutes 7 Seconds My Album's: engine_kid's album Thanks: 0 Thanked 0 Times in 0 Posts	does this happen more when you are in the higher rpm's or will it happen over time? im plannig on building a 347 with around 500hp maybe well see what happens.

10-24-2007	#9 (permalink)
Jasperstang308 Gold Member Join Date: Apr 2007 Posts: 189 iTrader: (0) Friends: (1) Last Online: 09-16-2011 01:56 AM Time Spent Online: 3 Hours 41 Minutes 29 Seconds My Album's: Jasperstang308's album Thanks: 0 Thanked 0 Times in 0 Posts	tuning is a BIG PART of it that and the machine work. there is a guy on another forum i hang out on is making i think it was 650 to the wheels with a F.A.S.T system

10-24-2007	#10 (permalink)
engine_kid engines turn me on Join Date: May 2007 Location: Grand Haven, MI Posts: 49 iTrader: (0) Friends: (0) Last Online: 10-29-2008 02:03 PM Time Spent Online: 4 Minutes 7 Seconds My Album's: engine_kid's album Thanks: 0 Thanked 0 Times in 0 Posts	damn thats sweet. i think mine is going to be carb'd but im going to put main girdle and valley girdles in to help strenghten the block a little. and studs on everything.

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