superstreeter

I need some quick info.....how tall are these blocks..I have a combo thats 10.205 tall..will I have room to clean the deck..Are they taller than 10.20...maybe 10.21 ?

hammertime

Ive only had one, but it was spot on 10.20 dart big m

oldandtired

I my dealings, a maching shop preps a tall deckat a target height of 10.180.
Hink can probably add some info.

zipper06

This is what Dart's tech sheet says. Although i've never measured a B/BLK, i do know the Little "M", which i've purchased 2 comes in .020/.025 taller= 9.020/9.025

Zip.

DART Iron Big Block - Technical Notes
Deck Height ................................................ 9.800" & 10.200"
Bore ................................................ 4.250" or 4.500" unfinished
Main Bearing Size ................................................ Standard BBC
Main Caps ................................................ All 4 bolt - Steel or Ductile Iron
Weight ................................................ 4.250" bore = 280lb / 4.500" = 260lb
Largest Recommended Bore .................................. 4.625"
Camshaft Diameter .................................. Standard BBC
Camshaft Position .................................. Standard BBC
Cylinder Wall Thickness, min. .................................. .300" @ 4.625" bore
Deck Thickness, min .................................. Adequate for all applications
Torque Specs - Main Caps 1 - 5 1/2" bolts 100 ft lbs
(with oil) 2 - 4 1/2" splayed 100 ft lbs
Dart’s inner head studs 3/8” – 7/16” stepped 50 ft lbs
Blocks with cam shaft diameters above 50mm require the use of Dart lifter bushings.
Standard BBC oil filter is used.
Standard BBC timing chain, timing cover, gear or belt drive can be used.
Actual deck height will be .005"- .010" taller for additional machining requirements.
Standard BBC oil pan can be used. Extra bolt holes are provided for stroker crank pan.
Cam bearing OD should be deburred before installation.
When removing main caps initially, the caps & block should be deburred before reinstalling. This will insure that correct
main size is maintained.
Standard BBC head studs or bolts may be used.
Head stud holes are blind. They do not go into the water jacket.
A sealant/antiseize must be used on the head studs. Loctite # 620 is recommended.
Studs should never be torqued into block. They should only be lightly snugged.
It is preferred that a bullet be machined on the end of the head stud where it bottoms in the block to center the stud before
tightening.

superstreeter

Thanx Zip
I was looking for some specs like that on the Dart block, I thought the deck height should be taller, mine specs out at 10.195. and I still have to clean 3-4 thou off.which leaves my combo about 13-14 thou. out of the hole. and now about a .060 gasket. not ideal. but I guess it will have to work

hink

We machine alot of Dart blocks in our CNC machine and so far most of them will clean with 10.200 and down as far as 10.198

So far I have never seen a 10.195 block so far and we probe out every block for cylinder location and deck heights.

superstreeter

Well I guess just for curiosity, I will measure the assembly, and see if the rest is out of wack, but as it stands,,,I'm .014 out of the hole, with the deck cleaned up about .004...never the less....shes going together.lol .060 gasket..

superstreeter

OK one more thing on my mind here, ... I'm measuring piston to head...I have .005 out of the hole...do I leave .040 clearance from there ?....or do I measure from the height of the piston rock, which seems to be about another .010, which now gives me .015 ?

Dont really want to wait till next week to find out here in town ..lol

zipper06

If you have a total of .010 rock from top side to bottom side and .005 in nutrual position. The piston will rock too the bottom on the compression stroke under power, that's a good thing because it will give you some extra valve clearance. But the answer is on the compression stroke you should be .010 out of the blk. If you're useing a .060 gasket that would be .050 on the tight side. I would suggest that you lay some clay on the dome to make sure you have dome clearance in the clyinder head on the sparkplug side, and for sure check the valve to piston clearance. I just put together a 481" that the cylinders were way too much clearance .008 and had .013 rock. But the guy was on a budget and couldn't afford another blk. I had .180 on the intake and .210 on the exhaust.

JMO

Zip.