Dart Head Issues
01-01-2006, 07:40 AM
#61
Originally Posted by SStrokerAce
Yep they fit just fine.... I checked all the clearances on the Pro Mag stuff before I assembled the heads.
Let me add that the extra material around the rocker bosses is a GOOD THING! The guys who race GM OEM heads in road racing weld up around the rocker bosses or they end up failing the heads in this area, DART fixed this problem from the factory, even though they can probably change the CNC program to help with clearance around the Crane and stock rockers.
Hopefully I will button up the car here soon, and the customer can take it and get it dyno tuned. I'm thinking around 450rwhp or more.... with 230/236 cam, 11.2:1, headers, a LS6 intake and ported TB. Don't know how much the SLP lid is going to hurt though.
Bret
Let me add that the extra material around the rocker bosses is a GOOD THING! The guys who race GM OEM heads in road racing weld up around the rocker bosses or they end up failing the heads in this area, DART fixed this problem from the factory, even though they can probably change the CNC program to help with clearance around the Crane and stock rockers.
Hopefully I will button up the car here soon, and the customer can take it and get it dyno tuned. I'm thinking around 450rwhp or more.... with 230/236 cam, 11.2:1, headers, a LS6 intake and ported TB. Don't know how much the SLP lid is going to hurt though.
Bret
I also modified my Crane valve spring tool to minimize the material I have to remove and keep the strength in the original Dart design. This should give me the best of both worlds
01-02-2006, 07:27 PM
#62
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OK, I have a set of 225s on order, and have been reading this topic with
great interest
while I was away on vacation last week. Now that I'm home, did some measuring of my own FWIW:
PN 12550592 '97-98 LS1 block: top of bore chamfer - 3.94" DIA.
PN 12558810 '98 GM graphite head gasket - 3.98" bore dia. -
probably explains the diameters used on the Cometics...
I don't have a stock 5.7 MLS gasket on hand...so you guys are saying there
is one with only a 3.91" bore...
That is very interesting IMHO...
great interest
while I was away on vacation last week. Now that I'm home, did some measuring of my own FWIW:PN 12550592 '97-98 LS1 block: top of bore chamfer - 3.94" DIA.
PN 12558810 '98 GM graphite head gasket - 3.98" bore dia.
-probably explains the diameters used on the Cometics...
I don't have a stock 5.7 MLS gasket on hand...so you guys are saying there
is one with only a 3.91" bore...
That is very interesting IMHO...
01-03-2006, 06:15 AM
#63
I recently found a part number for the 6.0 liter with a 4" bore. Comes in either MLS or graphite. I am going with the graphite since it is less critical on surface flatness just in case, although I usually do a very good job cleaning and preparing the surfaces.
Right now, the heads are apart and I am modifying for the Crane/Vinci valve spring tool and the Crane guide plates. Turns out if the tool fits, so will the guide plates. I will need this once the heads are on the car so valve spring swaps can be done later (planning ahead) as a preventative maintenance.
I also found that the valve spring shims are above the one piece seal/seat, never seen that before
Heads are beefy and they look like nice quality parts have been used.
Right now, the heads are apart and I am modifying for the Crane/Vinci valve spring tool and the Crane guide plates. Turns out if the tool fits, so will the guide plates. I will need this once the heads are on the car so valve spring swaps can be done later (planning ahead) as a preventative maintenance.
I also found that the valve spring shims are above the one piece seal/seat, never seen that before
Heads are beefy and they look like nice quality parts have been used.
