cn's small block chevy block

anyone had any dealings with the cn small block? i have read on here about their big blocks, but was wondering if anyone has a small block version? was reading some info on them and they make a 4.500 bore small block. they put a 4.250 crank in them and you can have a 540 sbc. is this crank a big block crank, and what rods do you run in this motor. have found only a couple heads that can fit this combo. was just wondering everyones thoughts on this setup, how much can one of these blocks take? just wondering because of weight rules, we can run anything, but the small blocks get a 300 pound weight advandage. so can you get the same horse out of a 540 sbc that you can get out of a 540 bbc? and get the motor to live? thanks in advance jeremy

 

Jerry Decker out of Louisville ran a CN S.B.C. a few years ago. I'm not sure on the c.i.'s but he ran the AJ small block heads.

Brandon Booher

 

underby6 is right Jerry ran the cn block and from what he told me he really liked it.
But I have a question for you why would you want to build a 540 smallblock?
What kind of advantage do you think you are going to gain?

 

get a 300 pound weight break if the two motors are able to make roughly the same horse and tourqe. big block has to weigh 2450 small block has to weigh 2150, so i can be 300 pounds lighter. does jerry decker have an email or phone number he could be reached at? thanks

 

sbc

Where did you find info on a bore that size? Got to believe the bore spacing is moved so much what heads fit that? I love sbc's and would like one that size too but I think you are looking at a lot of custom parts.

 

The 12 degree AJ Heads are for bore sizes 4.125 and larger. I would say call AJ (www.alanjohnson.com) and see what the exact specs are. I don't have a number for Jerry Decker, but my dad might, I'll see if I can find if for you. I know Greg Good ran the AJ Heads and Manifold, not sure if he had the CN Block as I think he ran Dart Billet. They're pretty cool heads though, same as the 481X where you can pull individual heads without removing the manifold.

Brandon Booher

 

cfe makes two heads that will fit that bore. the little chief and the sbx head.i have called and got info on both heads and block. just need a little info from someone that has ran this combo. and found cfe site from alan johnsons web site.

 

A SBC has a bore space of 4.48 i believe. How can you have a 4.5 bore? If you stretch the motor out to a (roughly) 4.75 bore spacing, then how can it be a sbc? A bbc has a 4.8 bore space.

 

Its does get kinda crazy,

But if Sonny can make an engine with 5.3 bore spacing and 5.08 bore and call it GM and CN can make a cross bolted main 5.0bore space and call it a BBC then I see no reason why you can't make a 4.5 bore block and call it a SBC just use SBC journal size or lifter location or some other feature shared by a SBC and SBC it is.

Richard Gavle

 

I dont know about a 500 or larger cu in SB. I have a CN billit block 400 SBC with AJPE heads 14.71 superman. Its a pretty wickid little motor, contact Darren Mayer of DMPE if you want more info. Its for sale Hat to Pan.

Rod

 

Are you sure you are not talking about the new nascar deal where they have increased the bore centerline of the small blocks to 4.5" from the old SB2 blocks that had a 4.4 bore centerline spacing? I believe nascar runs these blocks at a 4.185 bore.

 

heads

unless AJ has come up with a new head witch is not out of the queston the AJ small block head fits STD bore location. but I have eat a couple of tennis shoes before

 

small block

I can tell you there are different bore spacing on small blocks and still use the same crank. ????

 

cn billet small block

Call Chuck Nuytten at CN blocks,he can fill you in on what's possilbe,time frame to get one,cost,and recommend heads & components for it.
972-722-8333

 

have already called cfe talked to scott kieffer they make the sbx head how ever you want it? bolt on stock or the 4.5 bore spacing. cost 8500 ready to bolt on a 4.500 spacing motor.also have the cn 2008 catalog laying here. if i had a scanner i would post the info.looking at page 7 4.500 bore sbc. was just wondering if any one has run this motor and how reliable it was. so if anyone that has ran this, or knows someone that has tried this motor please email me. thanks jeremy

 

Watch your back. Some governing bodies are starting to put a limit on SBC's and making only the standard bore space blocks considered a small block. So far, I don't know of any drag race sanctioning bodies that have done so. But if they start, you could lose your weight break.

 

I was having a hard time comprehending a 4.5 inch bore small block chevy, so I emailed CN Blocks and asked what exactly was availabe bore wise with the new block. Here is what they told me:


"The block is designed on a 4.5" bore space. With this SBC you can build motors up to 560 cubic inches. Maximum recommended bore is 4.280 depending on application."

"This block with a 10.2 deck height, +1.029 high cam, 4.875 stroke, and 4.280 bore will get you to 560 cubic inches."


I hope this helps clear up the issue of a 4.5 inch bore. Although a 560 inch small block is huge to say the least.

 

hell just build a good bbc or hemi and same some money. and you are right im going to be the first one to try and stop the weight break for you guys .buddy

 

Why would you run so much displacement and have such a long stroke , wouldn't you want bigger bore then stroke?

 

I don't disagree with you building a small block and taking advantage of the weight break at all !
It worked great for Grumpy Jenkins it also worked pretty sweet for Laurie Cannister and Mick& Larry Snyder back in the old Pro Outlaw days. It also worked out pretty good for a guy by the name of Rick Santos... but I have a question???

Why such a big engine?:
I know the old phrase "there's no replacement for displacement" but that old phrase isn't so accurate ,there are replacements for displacement ,they are called boost, longevity and efficiency!

It seems to me a small block with that kind of stroke is going to have a lot of issues like, piston speed , tons of load on the piston skirts ,cylinder walls and wristpins. will you have enough meat between the cylinders with that huge bore to make enough clamping force hold the head gaskets?
That big stroke is going to make a lot of bend and twist on a small block crank (hope you have a crank sponsor) and is that long stroke and your small chamber heads going to allow you a strong enough, short skirted, dished piston to get down to say 11.5 to1 compression for a blown alcohol engine and will those heads and your blower going to efficiently feed that mini mountain motor?

I met Rick Santos a few years ago and had a discussion with him about engine size and I will never forget what Rick said to me, in short, what he said to me was "a smaller motor makes the head and blower more efficient"

Don't take me wrong ,I'm not cutting you down at all , I'm just offering you some friendly food for thought. I would hate to see you build the worlds most expensive hand grenade