thats what they need is more bore and less stroke

 

Part # 31253754
Material: Superior Iron Alloy
Bore: 4.250” thru 4.600”
Bore & stroke: 4.625” x 4.750” (max recommended)
Cam bearing bore ID: 2.120” Std.
Cam bearings: Coated, grooved, w/3 oil holes PN# 32210030
Cam bearing O.S. +.010”, +.020”, +.030”
Cam bearing press: .002”
Camshaft position: Standard
Cam Drive: Timing chain, Gear drive & Belt drive
Cam Plug: Standard BBC 2.215” diameter
Cubic Inch: 638 ci (Max Recommended)
Cylinder Wall Thickness: .300 Min @ 4.625” bore
Deck Height: 10.232” (259.89mm)
Deck Thickness: Adequate for all applications
Dist. Tap Hole Valley: Yes
Fuel Pump Boss: None
Fuel Pump Pushrod: None
Freeze Plugs: Std. Press in cup plugs 1 5/8 “dia.
Head Bolt Pattern: Std. GM
Inside Head Studs: None
Lifter Bores: .8427” - .8437” Machined for Gen 8.1L GM Hyd. Roller
Main bearing size: Std. BBC
Main bearing bore: 2.937” – 2.938”
Main caps: Ductile Iron 4 bolt (Steel option available)
Oil system: Wet or Dry Sump - Main Priority Oiling
Oil Galley, main: Stepped, 9/16” – 1/2” – 7/16”
Oil Cooler Holes: None (Can use aftermarket inline)
Oil Galley, filter main: 5/8”
Oil Filter: Stock oil filter location
Oil Pan: 8.1L Metric bolt pattern and oil pan
Rear Main Seal 1 piece, NO gasket groove Fel-Pro 2920
Hyd. Roller Provisions: Yes
Serial No. On main caps / Front passenger side below deck
Starter: Mounts in standard location
Stud & bolt holes: Blind tapped
Tapped Holes: Metric Thread & Pitch
Timing chain / gears: Std. BBC Gen VI / GM 8.1L
Timing Cover: Gen VI stock 6 bolt cover or GM 8.1L
Torque Specs: All ½” bolts – 105 ft lbs
Weight: 4.250” bore (295 lbs)
4.350” bore (280 lbs)
Block Prep Option: Available for additional fee (Call

 

I plan on having dart make me a billet 8.1 based block. Use 8.1 head bolt pattern.
and then going 4.500 bore and 4.250 stroke should be a nice twin turbo 540. Get a set of the raylar heads bare and do a maximum effort port job. 2.25 1.90 valves. 244 244 at .050 and .650 lift hydraulic roller so i can drive it. e85 and 30 pounds of boost should be fun..

 

this is some updates

 

I love all the 8.1 love. keep the pics coming. Im not sure why on the dart block they didnt put the 2 oil cooler line ports on it like the factory block...not a huge deal but kinda bums me out

 

Because dart just made they std tall deck block into an 8.1 block

 

im not shocked...easier for them production wize i just want bolt in and go with no mickey mouse bs. O well thats hot rodding

 

Yeah I know raylar complained to dart about the differences not sure if dart is dealing with it

 

looks good so far..

 

thanx