Although the price tag on these is high, what is the advantage of this block compared to a Dart Little M or a Motown block?
Is there an advantage of going with the 400 main rather than the 350 main?
What standard small block parts won't work with the taller deck version?
Can you use a wet-sump system in the tall deck, dry sump block, p/n 22551790?
Thanks in advance
:D

 

the 400 main is for strokers to get some overlap between the mains and rod journal. you will need a external oil pump if you want to use a wet sump pan on a rocket block. :chevy

 

My SBC427 is based off of the Dart Iron Eagle block, which is identical to the GM Rocket Blocks. Dart actually makes the Rocket Block for GM. The only difference between the blocks are the logo's cast into them, and the fact that a Iron Eagle block can be either wet or dry sump (depending on whether you plug the main cap or not), whereas the Rocket Blocks are machined so that they are either wet or dry sump. A dry sump block has a different part number than the wet sump block.

If you wanted to use the dry sump part numbered block, you'd need an oil pan with a -12 or larger bung and an external single stage wet sump pump. It's basically like a dry sump pump, but only has one pressure and one suction section. You'd simply scavenge from the pan and return the oil through the front/rear/both 1/2" NPT oil galley ports. The Dart Iron Eagle and the Rocket Blocks do not have block mounted oil filters, so you have to run a remote filter anyway. So adding an external pump wouldn't really require much more plumbing. One benefit of the external pump is that it allows you to run a full length windage tray, for better oil control and more horsepower.

In my opinion the Dart Iron Eagle or the Rocket Block is superior to the Motown blocks if you're building a serious stroker. The Dart and Rocket block feature .800" wider pan rails, and .391" raised cam location. The wider pan rails allows you to run a longer stroke, up to 4.25" without having to notch the pan rails. We only had to add a small 1/4" notch to the bottom of the cylinder bores with my 4.00" stroke crank. The taller cam location gives plenty of clearance for the cam and rods, which means you don't have to run a weaker small base circle camshaft or grind on your rods. Also, an additional benefit of the taller cam is that you can run shorter pushrods which makes the valvetrain lighter and more rigid.

Contrary to what World Products likes to say in their Motown advertisements, the wider oil pan and raised cam do not mean you have to run expensive pan and timing sets. You can get an oil pan for as low as $200. Summit sells a Moroso pan with windage tray, crank scraper, and trap doors for about $250, and you can get a custom Stef's aluminum sheetmetal pan for about $300 with all the same features. Cloyes offer a Tru-roller timing chain for the raised cam blcok for less than $100, and a standard timing cover fits just fine.

Another adavanctage of the Dart and Rocket blocks is that they are offered with the taller decks. I have the tall 9.325" deck block. The advantage is that even with a longer stroke, you can run a longer rod. Even with a 4.0" stroke, I am running 6.125" rods, which yields a 1.53 rod/stroke ratio. For comparison, the common 5.7" rod 383 has a 1.52 rod/stroke ratio. The longer rods reduce rod/crank angularity and cylinder side wall thrust loading. This will help reduce cylinder wall/piston/ring wear associated with poor rod/stroke ratios in strokers.

The only thing that really needs to be changed with the taller deck is the intake manifold and distributor. Since the decks are raised, this spreads the cylinder heads out wider. Dart makes several intake manifolds that will fit, or you can go with a custom sheetmetal manifold like my Hogan's. With these manifolds, you don't have to use spacers, but several company's do make spacers which allows you to use standard intake manifolds on a tall deck block. As for the distriubtor, you just need one with an adjustable collar, like those offered by MSD, since the distibutor sits slightly taller.

While the aftermarket blocks may seem more expensive at first, they are actually cheaper in the long run. These blocks are all machined to within .001", only requiring finish honing the bores to fit your pistons and rings. These blocks also have much thicker cylinder walls, decks, bulkheads and main webs compared to any production block. The cylinders can be bored to 4.200" and still have at least .300" thick cylinder walls. A production SBC 400 can have cylinder walls as thin as .090" on the thrust sides if the've been bored .030" over. This means the block is alot more rigid, providing better cylinder/piston ring sealing and a longer lifespan. If you added the cost of boreing, honing, decking, fitting for splayed main caps, cost of the splayed billet caps and studs, the cost of bringing the production block onto par with the aftermarket blocks is about the same. But the aftermarket blocks are still more heavy duty, with thicker walls, etc.

As mentioned already, the 400 mains offer better cross sectional overlap between the journals, making the crank stronger. I wnet with the 400 mains and BBC cam bearings for this reason. The BBC cam bearing option is nice because you can run a cam with more lift. My cam wouldn't fit into a SBC block without the BBC cam bearing size becuse the lobe has a taller radius (lift) than the a SBC cam bearing journal.





[Modified by Monty, 9:01 AM 11/11/2001]

 

Thanks for the info Monty :yesnod: & clem
I will be buying one of these blocks - Dart Iron Eagle or Rocket some time next year.
What is the Dart Little M?
I'm planning to get a tall deck version. The dry sump isn't a requirement, but if I'm going to spend that much, why not? What's the cost difference between the external wet sump system compared to the dry sump?
Also, I have a pair of dart pro 1 200 intake heads with 64cc chambers. Do you know if they can be opened up enough to support 427 + inches? (around 220?) I think gkull ported his to about 230, but not sure.


[Modified by 71coupe, 7:26 PM 11/11/2001]

 

The Dart Little M is basically just a heavy duty small block, the same as the World Products Motown block. It just doesn't have the raised cam, spread pan rails, or taller deck option.

A dry sump will add about $2000+ to the cost. The pumps are $800+, plus you need the external reservoir and all the hoses and fittings, and mounting and drive hardware.

I looked into it, and it's a real challenge to fit it all in. A cheaper alternative would be to run the external wet sump pump as discussed earlier.

You should have no problem getting those heads to flow whatever you need. In stock form they would do fine, it just depends on what kind of power you want. A rough estimate for determining a heads power potential is to multiply it's intake flow in cfm by 2. A 300cfm head could potentially support a 600hp motor.