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340 small block question.... #921007 02/04/11 02:48 PM 02/04/11 02:48 PM
Joined: Sep 2004 Posts: 22,873 Chicken coop dustergirl340 OP Chicken Little
dustergirl340 OP Chicken Little Joined: Sep 2004 Posts: 22,873 Chicken coop	What is the weak point on a factory 340 block? What is the most power you could push with one?

Re: small block question [Re: dustergirl340] #921008 02/04/11 03:04 PM 02/04/11 03:04 PM
Joined: Aug 2007 Posts: 1,564 St. Clair Shores, Michigan bigsbigelow pro stock
bigsbigelow pro stock Joined: Aug 2007 Posts: 1,564 St. Clair Shores, Michigan	Weak points: Minimal head bolts and webbing (T/A blocks had thicker webbing). Horse power limit: You will get thousands of different answers to that question. There has been a lot of discussion on this and not one opinion seems to match another. Last edited by bigsbigelow; 02/04/11 03:05 PM. Ryan "Bigs" '73 Duster (BLKDUST) - Black, 100% factory sheet metal, flat hood, 346 cid, J Heads, and a bench seat. http://s268.photobucket.com/albums/jj1/bigsbigelow/ Best to date: 12.40 @ 109 mph

Re: small block question [Re: dustergirl340] #921009 02/04/11 03:05 PM 02/04/11 03:05 PM
Joined: Mar 2004 Posts: 2,475 SW Ohio C cgall top fuel
cgall top fuel C Joined: Mar 2004 Posts: 2,475 SW Ohio	I've seen Prochamp run 9.9's with a stock stroke 340 and 3200 lb. car. Must be over 600 HP. He spends a lot of time adjusting his valve train, though.

Re: small block question [Re: dustergirl340] #921010 02/04/11 03:09 PM 02/04/11 03:09 PM
Joined: Jan 2007 Posts: 3,695 nc E emarine01 master
emarine01 master E Joined: Jan 2007 Posts: 3,695 nc	They say that 600hp is around the factory block limit, There are a lot of mods that need to be done on the oiling system to get a factory block to live, A lot will have to do with how far you push the bore and stroke

Re: small block question [Re: bigsbigelow] #921011 02/04/11 03:14 PM 02/04/11 03:14 PM
Joined: Sep 2004 Posts: 22,873 Chicken coop dustergirl340 OP Chicken Little
dustergirl340 OP Chicken Little Joined: Sep 2004 Posts: 22,873 Chicken coop	Quote: There has been a lot of discussion on this and not one opinion seems to match another. Yeah, I know, but it's interesting to read different opinions and the search feature on this site isn't the best.

Re: small block question [Re: dustergirl340] #921012 02/04/11 03:21 PM 02/04/11 03:21 PM
Joined: Aug 2004 Posts: 2,128 sweden S sshemi top fuel
sshemi top fuel S Joined: Aug 2004 Posts: 2,128 sweden	my w5 stroker made over 600hp on a stock 340 block with studs and a toy girdle, but it also suffered from capwalk.

Re: small block question [Re: dustergirl340] #921013 02/04/11 05:56 PM 02/04/11 05:56 PM
Joined: Dec 2006 Posts: 3,396 Pa Hot 340 master
Hot 340 master Joined: Dec 2006 Posts: 3,396 Pa	The weak point is the cylinder walls.

Re: 340 small block question.... [Re: dustergirl340] #921014 02/04/11 07:07 PM 02/04/11 07:07 PM
Joined: Jun 2010 Posts: 3,112 LONG ISLAND fishy340 master
fishy340 master Joined: Jun 2010 Posts: 3,112 LONG ISLAND	Quote: What is the weak point on a factory 340 block? What is the most power you could push with one? good friend of mine goes mid 9's 3000+car stock block! point blank it"ll handle more than a stock 440 block

Re: small block question [Re: Hot 340] #921015 02/04/11 07:55 PM 02/04/11 07:55 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: The weak point is the cylinder walls. This might be the weak point... I have cracked a few walls in my assortment of 340 blocks... I've never run a girdle... I've only blown one head gasket but the most compression I've run on a stock block was 12.4 but I do believe in buzzing them... normal for me is 8200 on my 395ci W-2 but have been a fair bit higher

Re: small block question [Re: MR_P_BODY] #921016 02/04/11 08:09 PM 02/04/11 08:09 PM
Joined: Jan 2003 Posts: 42,714 Spokane Washington ScottSmith_Harms Mr Wizzard
ScottSmith_Harms Mr Wizzard Joined: Jan 2003 Posts: 42,714 Spokane Washington	As mentioned, being a thin wall casting (all production line 340's) makes the cylinder walls potentially thin even when they have standard bores. Core shift (common) can compound the problem. I have also noticed that the lifter valley areas can crack when stressed (big power/overheated/freeze cracks). If you find an example that passes a mag check for cracks and is finish bored and sonic checks good to around 200 thick on all the thrust sides of the cyliners (most fall at 150-180, 200 is a primo example) you can likely run the power up to around 550 without worry. It may live at higher power levels but it's a total crap shoot after that, block filler will likely help a lot but pretty much makes it a race only piece at that point. If your target is over 500HP my advice would be to invest in a new R3 or Resto 340 block to build if you can afford one ($2,500.00 or so) so you start with a strong foundation, these thicker/stronger blocks can hold up to well over 1,000hp.

Re: small block question [Re: MR_P_BODY] #921017 02/04/11 08:09 PM 02/04/11 08:09 PM
Joined: Oct 2008 Posts: 261 Wisconsin BLONDE BARRACUDA enthusiast
BLONDE BARRACUDA enthusiast Joined: Oct 2008 Posts: 261 Wisconsin	I run a half filled 340 stroker car weighs 2985 not sure of horse power studed block factory caps

Re: small block question [Re: BLONDE BARRACUDA] #921018 02/04/11 08:11 PM 02/04/11 08:11 PM
Joined: Oct 2008 Posts: 261 Wisconsin BLONDE BARRACUDA enthusiast
BLONDE BARRACUDA enthusiast Joined: Oct 2008 Posts: 261 Wisconsin	forgot to mention car runs 9.70s

Re: small block question [Re: dustergirl340] #921019 02/04/11 09:17 PM 02/04/11 09:17 PM
Joined: Nov 2009 Posts: 3,410 Belpre,Ohio C CHAPPER master
CHAPPER master C Joined: Nov 2009 Posts: 3,410 Belpre,Ohio	Quote: Quote: There has been a lot of discussion on this and not one opinion seems to match another. Yeah, I know, but it's interesting to read different opinions and the search feature on this site isn't the best. I will have to say,,THIS is with out a doubt, the most accurate desription of this site I have seen!!! If you like drag racing, support your local track.

Re: small block question [Re: ScottSmith_Harms] #921020 02/04/11 09:21 PM 02/04/11 09:21 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: As mentioned, being a thin wall casting (all production line 340's) makes the cylinder walls potentially thin even when they have standard bores. Core shift (common) can compound the problem. I have also noticed that the lifter valley areas can crack when stressed (big power/overheated/freeze cracks). If you find an example that passes a mag check for cracks and is finish bored and sonic checks good to around 200 thick on all the thrust sides of the cyliners (most fall at 150-180, 200 is a primo example) you can likely run the power up to around 550 without worry. It may live at higher power levels but it's a total crap shoot after that, block filler will likely help a lot but pretty much makes it a race only piece at that point. If your target is over 500HP my advice would be to invest in a new R3 or Resto 340 block to build if you can afford one ($2,500.00 or so) so you start with a strong foundation, these thicker/stronger blocks can hold up to well over 1,000hp. My self I wouldnt worry about a stock block till I was over 600 hp but I would want a good balance... I dont mind putting a sleeve or two into a good 340 block.... I've got 4 good ones now... my 416 going into my Rampage for my drag week car will be in the area of 550 hp and I dont foresee any issue ... I also try to keep the bore size down to a .030 or .040 over bore

Re: small block question [Re: Hot 340] #921021 02/04/11 09:28 PM 02/04/11 09:28 PM
Joined: Apr 2003 Posts: 3,525 Tulsa, Oklahoma 340Cuda master
340Cuda master Joined: Apr 2003 Posts: 3,525 Tulsa, Oklahoma	Quote: The weak point is the cylinder walls. We have even busted cylinders on blocks that were half filled with HardBlok.

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