well i thought i had my combo figured all out, untill i spoke to machine shop. i want big inch sbc 434. when all parts and labor totaled shop wants 1200-1400 to race prep and clearance cust. supplied block. I can buy dart m block for 2000 brand new. please steer me in the right direction on this one because spring is right around the corner.
Dart block. They are designed to go big inch. The 400 was never intended to go out to 434 and it gets thin in the walls and critical areas. Many 400s are running there at 434 but it is risky. If you are going to be putting serious power and rpm to it the Dart is good insurance.
The Dart Block is a better block but I don't think the Little M you are looking at can be purchased as a tall deck. Now with a 4 inch crankshaft in it and a 6 inch rod you will be limited to a 1 inch pin height piston. There isn't a problem with that but some people are a little uncomfortable running these in street engines and that is simply your choice. The Iron Eagle blocks offered by Dart can be purchased 0.300 tall giving you a lot more options. With this block you can either run a lot more rod length or keep the shorter rod and have more piston up top. There are pros and cons to both and that decision is really answered by the application and intended use. One problem with a tall deck that I have experienced is intake manifolds that don't line up. If you have the tooling and time you can make something work just fine but it is something to consider. Either way you are better off strength wise going with the aftermarket unit and the cost may even be about the same a few years down the road if you factor in the “what ifs” on the seasoned block.
A Dart block would be the way to go as they are alot more dependable over a stock GM block and a Little-M Sportsman block line honed, decked to your demension, Blue print bored, plate honed, lifter bores clearanced amd the the water holes in the decks matched to the head gasket cleaned and shipped to your door for 2395.00
But with a 4 inch stroke it may require some extra clearance work.
Location: Mississauga, Ontario I know all the answers it's the questions I don't understand
I wrasselled with the same thing recently. The Dart Little M is nice but it still requires clearancing. THe World Motown will take a 4 inch crank out of the box, just requires a finish hone to your pistons.
I ended up buying a OEM 400 block, figure I will spend the $1000 difference on other parts. It is a hobby for me so I don't mind the clearancing etc. that is nessessary to make it compatible with a 4 in. crank. Heck, I don't even need another motor come to think of it Did I go the wrong direction here ? I don't know only time will tell
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Even with a "good" 400 block, its most likely 30 years old, iffy that you won't hit water trying to fit that 4" crank & rods in the case, staying with a 406 is safer & cheaper but I'd go aftermarket.
The aftermarket blocks are stronger, but a few guys in C-4 Tech are doing, or have done 4" cranks in 400"OEM blocks. They've all used some block-fill to be safe with the clearancing. Try a search there or here.
Don't waste your money on a stock block. In the long run you will save money going with a Dart, Motown, World, etc... The factory blocks are 25+ years old, and not made for a 4" crank. Even with clearancing for the crank and rods there are still issues with cam clearance. Block filler is fine in a drag race only application and not suitable for street use. If you want to use the stock block have it magnafluxed to ensure that it is not cracked. Splayed caps on a 2-bolt block are much stronger than a 4-bolt.
Don't waste your money on a stock block. In the long run you will save money going with a Dart, Motown, World, etc... The factory blocks are 25+ years old, and not made for a 4" crank. Even with clearancing for the crank and rods there are still issues with cam clearance. Block filler is fine in a drag race only application and not suitable for street use. If you want to use the stock block have it magnafluxed to ensure that it is not cracked. Splayed caps on a 2-bolt block are much stronger than a 4-bolt.
Tell me more about this" block fill in a street motor" thing. I've never heard of this being a problem, as I believe I've read about a few guys on the Forum useing it in street motors without problems. It doesn't seem to me like an inch or two would hurt anything. I've heard of slightly higher oil temps, but I think that was with a much higher fill. You get this info from a good source? Personal experience? I'm not really questioning you, I just want to know more about it, as I've never used the stuff, and It played a big part in my future plans too. Thanks to all
I only have the Motown iron with 350 mains. But if you saw any one of the aftermarket blocks you would not buy a stock block again.
IMO - I over the years spent lots of money on various splayed cap partial epoxy filled stock blocks. I've even owned sleeved motors. You just can't beat the modern designs. I think any new project I do would even jump into the LSX or "Warlock blocks"
This spring GM is going to release their new SB with 6 bolt mains and 6 head bolts in the block. Will go out to 512 cid and cost no more than a Dart block. I bet it is only a short time before all the major head manufactures are making the 6 bolt heads.
This would be ideally suited for nitrous or supercharging with the 6 head bolts.
This block is designed for wet or dry sump and better oiling system than the old blocks.
As far as the oem block many sell it way short. I have one that I made into a 406 and have been running it with a D1-R procharger @ 17psi and a 150 shot of Nitrous for the past 6 years with no problems.
The aftermarket blocks are much better but built right the oem can be made to withstand pretty good power output.
Location: Boston, Dallas, Detroit, SoCal, back to Boston MA
Quote:
Originally Posted by black bart
This spring GM is going to release their new SB with 6 bolt mains and 6 head bolts in the block. Will go out to 512 cid and cost no more than a Dart block.
LSX or GenI?
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BRIAN I saw this info on TV I think it was for both style motor mounts but don't remember for sure.
This will be available as a aftermarket item only.
It is not going into any new cars at this time.
They said the price should be between $2000.00 and $2300.00.
The article also said that GM had done extensive testing on it at 2300 HP and it was rock solid reliable.
At that price and that CID with that kind of strength I think it is a no brainer as to what block to buy.
I like the extra clamping force of the 6 bolt head. This will allow for serious power.
I'm sure that when it becomes available in the spring we will learn more details about it.
Last edited by black bart; 01-31-2007 at 10:08 AM.
I went with a World Products block for my race motor and then reworked a 400 2bolt main for my spare.
By the time I had finished changing the spare to 4blt caps, all the machine work and checking, I was 75% of the price of the new block... and the reworked one had so much slop in the timing chain from the align bore of the mains that it was hard to set up the cam... it was certainly not 1/2 the block that the new one was.
World Products CNC 4 bolt billet steel caps at all locations +dowels. 4.185 max bore with still .250 wall thickness, indexed lifter bores, priority main oiling, pre-clearanced for big crank, external oil feed boss.
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sbc dart iron block vs. worked 400
Did I go the wrong direction here ? I don't know only time will tell 
