kb944's and 954's $352.95

[dwg86]

I may have to buy a set at that price!!

http://www.cnc-motorsports.com/brand.as ... tgID=29442

[Muad'Dib]

Nice price.

[dwg86]

They also have Jeep 6, Crower aluminum roller rockers for $269.00, and stainless roller rockers for $301.00. Good prices.

[Plechtan]

Slightly off topic, I went to look at what CR i would get with the KB944 and how much below deck it would be assuming a stock 4.0 rod and stock block. No answer in either piston FAQ or CR FAQ. Perhaps we should add this information for all the pistons as a quick reference under piston FAQ. If someone wants to deck their block at least they will know what they are starting with. Most people seem to do 4.5 or 4.6 strokers anyway.

[gradon]

The comp height is 1.353" on those, so when used with the 6.123" 4.0 rods, the piston is .0295" down in the hole(based off a 9.453" deck height--a whopping .010" or so better clearance than the 4.2 rods and available stock/aftermarket pistons)--KB assumes you deck .020" in their spec'ing. I use the general board discussion calculator since it has the input for comp height and calculates deck clearance instead of you having to manually input the deck clearance in the newer calculator. That is a very reasonable price for forged pistons--falls right into place with the pricing of the other forged pistons kb sells(albeit they get an extra 2 pistons for that price). If only they would've went with a comp height of 1.380" or else permitted the use of the eagle 6.150" rods(then the piston would be down about .002-3"). I would've bought them last may for this price if they would've been available(1st batch was flawed).

[Plechtan]

So if you went .030 over, and used a .043 gasket, you end up with about a 9.2 cr with the piston down in the hole .020 (kb944) if you shaved the block .010 you are still at only about 9.4 cr with a .055 quench. Not the best but not bad for off the shelf parts.

[gradon]

The kbs are ~.030" down the hole, so you'd have to deck .020" to get the .010" clearance.

[Plechtan]

Or maybe offset grind the crank, if you used ,o60 oversize bearings, you could get a zero deck,

[Biggrnjeep97]

Has anybody used this company yet? I just ordered a set of pistons from them. I was also going to order a set of rocker arms but dont know what the rocker boss size is on a 4 liter. 7/16 or 3/8?
-Will

[dwg86]

It's 5/16. You can use comp studs that are 5/16 bottom 3/8 top they are for a Chrysler magnum engine. Crower also sells a set.

[drstrange]

I order a set of .030 over with the rings. Arrived promptly. No issues. The were in sealed boxes from KB.

[Biggrnjeep97]

Good to know there a reputable company. Good shops are becoming hard to find. I ask about the roller rockers because cnc-motorsports sells a crower aluminium rocker set in 3/8 and 7/16. Are these sizes describing the thread that screws into the head or the size that attaches the rockers. If the head needs the bosses redrilled/milled does anybody think there may be an issue with the 7/16 stub going into the water jacket or into the runners????

[dwg86]

The 3/8 or 7/16 is the size of the hole in the rocker arm. I would not drill the rocker bosses any bigger. If you look at some of the pics of the heads that were cut in half on a bandsaw, you can see there is not enough material in the head to enlarge the bolts and it will crack. Use the 5/16 bottom and 3/8 studs made for the chysler magnum engines. That is what I used with my Crower rockers, along with comp cams oldsmobile guide plates. I used the instructions from Harland Sharp on installing thier rockers on a jeep 6. They say to mill .400 off the rocker bosses. That is too much to mill off using the comp cams rocker studs. Ther is not enough thread engagement on the rocker adjusting nut. I would only mill .150 to .200. That's enough for the larger roller rocker fulcrums to clear the head. Check with your machine shop to see what they reccomend.

I think the Crower magnum studs are longer on the top than the comp studs. The dimensions are on Crower's web site. The longer stud would give more threads for the rocker nut.

[Biggrnjeep97]

The 3/8 or 7/16 is the size of the hole in the rocker arm. I would not drill the rocker bosses any bigger. If you look at some of the pics of the heads that were cut in half on a bandsaw, you can see there is not enough material in the head to enlarge the bolts and it will crack. Use the 5/16 bottom and 3/8 studs made for the chysler magnum engines. That is what I used with my Crower rockers, along with comp cams oldsmobile guide plates. I used the instructions from Harland Sharp on installing thier rockers on a jeep 6. They say to mill .400 off the rocker bosses. That is too much to mill off using the comp cams rocker studs. Ther is not enough thread engagement on the rocker adjusting nut. I would only mill .150 to .200. That's enough for the larger roller rocker fulcrums to clear the head. Check with your machine shop to see what they reccomend.I think the Crower magnum studs are longer on the top than the comp studs. The dimensions are on Crower's web site. The longer stud would give more threads for the rocker nut.

Thanks for the clarification. I saw the pics of the head and was concerned. I checked the crower website and i thought it was a bit generic, saying "machining required".
-Will

[TheDarkSideofWill]

If only they would've went with a comp height of 1.380" or else permitted the use of the eagle 6.150" rods(then the piston would be down about .002-3").

Why can't the Eagle rods and KB pistons be used together?