Anyone out there have hands-on experience with the Dart block. I have a C-4 vette that I'm planning on building a 427 or 434 block and was deciding on either a Bill Mitchell Mowtown II 427 prepped short block, or build my own 427 or 434 from a Dart block. I have heard that the Dart block is a better product and if so, was wondering how much pain it is to modify the tall deck to get it into a C-4 vette. I know this is the C-3 section, but I have to admit that when it comes to hands-on roll-your-sleeves-up experience, you guys have it.

Anyone with the knowledge on this topic, please enlighten me...

Bruce aka, the "BlackRocket"!!!!

 

This is probably a better post for the engine mods section. Monty has experience with the Dart block, which he's now adding twin turbos to for ~1300 hp on pump gas.

I believe that the Dart block allows for more stroke (4" vs. 3.875") without having to clearance the block. :)

 

You can't really compare the c-3 and c-4. C-3's can handle big blocks even 502's. I have near zero clearance with big heads and tall valve covers on the SBC stroker motor. I barely clear the heater/AC air box and the power brake booster on the other.

The tall Dart small block is less than 1/2 inch taller deck. Which because of the V angle might only raise the intake 1/4 inch. My next motor with be a dart 420+ ci and I'm going belt driven power assist on the brakes.

If your really worried about how much you might have to change. Just put a pan and heads on the bare block and do some trial fittings. I had my complete motor in and out 3 times to figure out clearancing.

 

I built my SBC427 using a tall-deck Dart Iron Eagle block. Dart actually makes the "Rocket" block for GM - they cast and machine it. The Iron Eagle is identical to the Rocket block except that the Iron Eagle is capable of being either a wet or dry sump, depending on how you plug it, whereas the rocket is offered under two different part numbers depending on if you want a wet or dry sump.

I used part number 31122222, which is a tall 9.325" deck block, with splayed steel mains, 400 main size, and Big Block cam bearings. All of the blocks feature a .391" raised cam, and .800" spread pan rails, .400" each side.

Contrary to what World Products/Bill Mitchell Hardcore implies in their advertisements, the use of a raised cam and spread pan rails does not require expensive race only hardware. Summit offers a pretty decent Moroso oil pan for this block in their catalog for $250, and Stef's can make you a custom sheetmetal aluminum pan for it for around $300. These are both good pans too, with kicked out saumps, teflon screens, trap doors, and include the pump and pickup I think. Felpro offers pan gaskets for it for about $25.00. As for the raised cam, Cloyes offers a Tru-Roller timing chain for it for about $95, and a stock timing cover and gasket fits it just fine.

Even the tall deck, if you chose does not add alot to the cost. Dart sells the necessary spacers for $40, or you can use one of their single plane intake manifolds that are designed for the tall deck blocks - and convert it to EFI if you chose. You don't have to go with a custom Hogan's sheetmetal intake manifold like I did if you don't want.

I have also helped two guys build SBC 427's based off of the HArdcore Motown SBC427 shortblocks. They are good blocks and the shortblocks are a rpetty good deal if you're satisfied with the quality of the components he uses. My only reservation is that there have been reports of the main webs cracking around the 1/2" main bolts/studs. There isn't alot of material left on the sides, they didn't widen the mains to accomodate the larger bolts/studs. I heard they were going to go back to 7/16" mains bolts/studs, so maybe they did if there is a Motown II block out now. This has only been a problem on very high output motors (like 800hp+), so it porbably isn't a concern if you're just gonna built a typical 600hp/7000rpm street or street/strip motor.

I don't know all the specific details of the Motown blocks, but the Dart block is what I'd recommend based on having used a couple of Dart blocks myself, and having helped build some Motown blocks - plus what I've seen in the NMCA/NSCA scene.

If you want all the specs on the Dart block, they are detailed on my webpage

http://www.montygwilliams.com . go to Engine, then Block.


[Modified by Monty, 1:09 PM 1/17/2002]

 

That's one awesome motor Monty!!! How many $$$ do you have tied to it??? :eek: :eek: :eek: