289 better than 302 block for 331 build?

BLIND MULE · 06-09-2012, 04:36 AM

Are they stronger?

BlueOval Ralph · 06-09-2012, 10:41 AM

Try to find a Old Boss block if you can any C8FE are Good D0ZE-A is bad a round bore D0ZE-B was back to square bore D1ZE-A are good you can safely go .065 over on any of these old block or if you can spend the money a new Boss 302 windsor block is good. The D1ZE had about .040 taller deck

partsbob67 · 06-09-2012, 11:15 AM

they might be stronger, but the cylinders are a little shorter on the bottom.

BlueOval Ralph · 06-09-2012, 01:40 PM

Doesn't hurt bit. We first built 342's, 337's, and 323 in the tail end of 1971
342. 4.060 x 3.30
337. 4.060 x 3.25
323 4.060 x 3.125
Boss 302 blocks are notched on the bottom of climbers for rod bolt clearance
Even built a 356 in 1972 4.080 x 3.40 had a 5.20 rod had to machine the bottom of crank throws flat to keep pistons from hitting the throws a real pain to internal balance Mallory in end two counter weights.

Quote:

Originally Posted by partsbob67

they might be stronger, but the cylinders are a little shorter on the bottom.

RJ Sledge · 06-09-2012, 02:12 PM

New Ford BOSS blocks are great except in Ford's infinite wisdom, they cut the bottom off the cylinders for stroker combo's(rod clearence), when you do this the wrist pin hole gets very low and sometimes (3.400 stroke combos) you can have the wrist pin (exposed) and that makes for a highly unstable situation as far as piston and ring positioning. To me the most important position is when the piston starts its upward movement in the cylinder. A wobbling/unstable piston at the bottom of the cylinder is not good for ring seal.

Eary model "R" blocks (SVO) are the way to go for 3.400 stroke combos IMO.

RJ

Jesse Kershaw · 06-13-2012, 09:32 AM

I would like to clear the air on the "short" cylinder walls because it's a common misconception.

We have sold thousands Boss 302 blocks, and 347 strokers, now 363 strokers, built off the Boss 302 block. We use a 347 for our sealed circle track program since 2008 with the Boss block. We have never had a failure from piston instability or anything related to the short cylinder wall length. All of these are done with 5.4" rods, if you're trying to do a bargain stroker with stock 302 rods then why look at a new block?

We shortened the wall for weight and to ENABLE stroker engines so they didn't have to grind for clearance depending on what crank they used. I am aware of a handful of 3.5" stroke engines in the ~370cid range also that have never had an issue. In fact our prior director Brian Wolfe had a 3.5" stroke in his personal Boss 302 block engine.

Due to early claims from many engine builders about the cylinder wall length we ran a second durability on the block and 347 crate engines about a year after its initial release. 1600 laps in a circle track for one, and 30 hours of dyno time varying between idle, peak power and peak torque for another. The result was perfectly fine blocks and pistons.

I have contacted 4 different shops that alleged to have failed engines with the block and upon investigation they had never even built one OR had built one and it never failed.

I can think of one customer who built his engine with a Boss 302, scuff a piston and immediately blame the block because of internet chatter. I spoke to him personally at an event. I asked for more info, like pictures? Are the ringlands intact? Are there signs of detonation? What was the piston to bore clearance? I never heard back again.

The Street Rodder 2008 Road Tour car ran a Boss block 347 and drove all over the country and then some. It's never had a single issue and the program director Jerry Dixey told me that it was the easiest engine he had to date because he never had to touch it during the trip. This year they are doing a new 5.0L in case you're interested.

Our 2010 Cobra Jet 352cid combo is a 3.4" stroke with the Boss 302 block as is our 2013 363 combo. Those have proven very reliable on the track.

I admit that at first glance the Boss 302 bore looks different but if there was truly this massive issue we would have changed the block or stopped selling 347/363's long ago. We cannot afford engine failures against our brand.

Everything above is fact.

Now for my opinion...

I believe this rumor about block failures is largely the work of our competition and their distributors who have a vested interest in selling their product. Shortfalls in their product have been brought to my attention but I would rather talk up the benefits of ours like the grade of iron, the crossdrilling between cylinders for street cars, finished lifter bores, and value vs. performance.

I also believe that if your engine builder is convinced that something isn't what they like, and your engine fails they will point to what they didn't like whether it was relevant or not because it's no money out of pocket for them. There are plenty of builders that love the Boss 302 block or we wouldn't continue to sell them like we do.

Thanks for your consideration.

-Jesse

06-09-2012, 04:36 AM	#1
BLIND MULE Member Join Date: Dec 2002 Location: Alabama Posts: 318 Likes: 0 Liked 0 Times in 0 Posts	289 better than 302 block for 331 build? Are they stronger?

06-09-2012, 10:41 AM	#2
BlueOval Ralph Banned Join Date: Feb 2008 Posts: 852 Likes: 0 Liked 0 Times in 0 Posts	Re: 289 better than 302 block for 331 build? Try to find a Old Boss block if you can any C8FE are Good D0ZE-A is bad a round bore D0ZE-B was back to square bore D1ZE-A are good you can safely go .065 over on any of these old block or if you can spend the money a new Boss 302 windsor block is good. The D1ZE had about .040 taller deck

06-09-2012, 11:15 AM	#3
partsbob67 Member Join Date: Apr 2005 Location: rohnert park,ca Posts: 414 Likes: 11 Liked 79 Times in 11 Posts	Re: 289 better than 302 block for 331 build? they might be stronger, but the cylinders are a little shorter on the bottom. __________________ bob beals 7244

06-09-2012, 02:12 PM	#5
RJ Sledge Senior Member Join Date: Jun 2007 Posts: 783 Likes: 496 Liked 288 Times in 90 Posts	Re: 289 better than 302 block for 331 build? New Ford BOSS blocks are great except in Ford's infinite wisdom, they cut the bottom off the cylinders for stroker combo's(rod clearence), when you do this the wrist pin hole gets very low and sometimes (3.400 stroke combos) you can have the wrist pin (exposed) and that makes for a highly unstable situation as far as piston and ring positioning. To me the most important position is when the piston starts its upward movement in the cylinder. A wobbling/unstable piston at the bottom of the cylinder is not good for ring seal. Eary model "R" blocks (SVO) are the way to go for 3.400 stroke combos IMO. RJ

06-13-2012, 09:32 AM	#6
Jesse Kershaw Member Join Date: Apr 2009 Posts: 108 Likes: 6 Liked 122 Times in 11 Posts	Re: 289 better than 302 block for 331 build? I would like to clear the air on the "short" cylinder walls because it's a common misconception. We have sold thousands Boss 302 blocks, and 347 strokers, now 363 strokers, built off the Boss 302 block. We use a 347 for our sealed circle track program since 2008 with the Boss block. We have never had a failure from piston instability or anything related to the short cylinder wall length. All of these are done with 5.4" rods, if you're trying to do a bargain stroker with stock 302 rods then why look at a new block? We shortened the wall for weight and to ENABLE stroker engines so they didn't have to grind for clearance depending on what crank they used. I am aware of a handful of 3.5" stroke engines in the ~370cid range also that have never had an issue. In fact our prior director Brian Wolfe had a 3.5" stroke in his personal Boss 302 block engine. Due to early claims from many engine builders about the cylinder wall length we ran a second durability on the block and 347 crate engines about a year after its initial release. 1600 laps in a circle track for one, and 30 hours of dyno time varying between idle, peak power and peak torque for another. The result was perfectly fine blocks and pistons. I have contacted 4 different shops that alleged to have failed engines with the block and upon investigation they had never even built one OR had built one and it never failed. I can think of one customer who built his engine with a Boss 302, scuff a piston and immediately blame the block because of internet chatter. I spoke to him personally at an event. I asked for more info, like pictures? Are the ringlands intact? Are there signs of detonation? What was the piston to bore clearance? I never heard back again. The Street Rodder 2008 Road Tour car ran a Boss block 347 and drove all over the country and then some. It's never had a single issue and the program director Jerry Dixey told me that it was the easiest engine he had to date because he never had to touch it during the trip. This year they are doing a new 5.0L in case you're interested. Our 2010 Cobra Jet 352cid combo is a 3.4" stroke with the Boss 302 block as is our 2013 363 combo. Those have proven very reliable on the track. I admit that at first glance the Boss 302 bore looks different but if there was truly this massive issue we would have changed the block or stopped selling 347/363's long ago. We cannot afford engine failures against our brand. Everything above is fact. Now for my opinion... I believe this rumor about block failures is largely the work of our competition and their distributors who have a vested interest in selling their product. Shortfalls in their product have been brought to my attention but I would rather talk up the benefits of ours like the grade of iron, the crossdrilling between cylinders for street cars, finished lifter bores, and value vs. performance. I also believe that if your engine builder is convinced that something isn't what they like, and your engine fails they will point to what they didn't like whether it was relevant or not because it's no money out of pocket for them. There are plenty of builders that love the Boss 302 block or we wouldn't continue to sell them like we do. Thanks for your consideration. -Jesse __________________ Jesse Kershaw