So its time to put together my new engine. I will break it down into each group.
Compression:
Right now I am have tighter gaped piston rings to allow less blow by past. I wanted to run 0.02'' gap piston rings, the machine shop said I needed to be at 0.028 minimum so I put them at 0.024''.
Then I bumped the compression from 7.9: to 11:1
Higher compression should give more power and better fuel economy.
Had to have the machine shop bore out the engine 0.03 over because some of the cylinders were badly tapered from a leaking cylinder head gasket allowing coolant to wash away the oil from the cylinders.
Preheating:
I left 2 open freeze plug spots for 600 watt engine block heaters. Then once I have the oil pump pickup connected and installed I am going to cut a hole in the oil pan to install a oil sump heating element.
Bearing clearance:
Right now I am working on the rod and main bearing clearance. The main bearings are on the loose side of .004 that would work but I would like to get a little tighter closer to .003 inches. Tighter bearing clearance will allow me to run thinner oil which will make starting easier and give better fuel economy and will allow the engine to wear more before its warn out.
The most correct way to fix that is go buy a set of -.001 undersize bearings and mix and match them with the standard bearings to get the desired clearance.
Roller conversion:
The old cam used flat lifters. I have gotten a comp camps roller conversion set. The roller cam also creates about 16 more foot pounds of torque through the entire operating range. The benefits of that are easier starting, better fuel economy and now I wont have to look for much more expensive SH and SJ rated oils I can use cheaper normal oil. The depleted additive package in SN and SM passenger car motor oils can cause a flat tappet lifter to wipe a cam lobe off the cam shaft. GM claimed the roller cam made a 1.5mpg improvement on their small block powered vehicles with the roller cam compared to the same engine with flat tappet cams.
I also picked up a set of full roller rockers, because why not?
Stroker:
Went from a 4 inch stroke to a 4.25 inch stroke crank to give more torque on the low end. I would like to get the cruise RPM down to between 1,200 to 1,400 RPM at 75mph.
The boring and the stroking should bring the engine displacement up to 489 cubic inches or right about 1L per cylinder. So it will have plenty of power to putt a long at 75 to 80 MPH at unusually low RPM even in thin air found at high elevations here in NM. In texas or new mexico all the speed limits are 75mph. I would have to drive at least 8 hours before I got to a state that didn't allow 75mph highway and interstate speed limits.
Weight reduction:
I tossed the 77 pound each cast iron heads, the 55lb cast iron intake manifold for aluminum and tossed the 20lb each cast iron manifolds for tube headers.
Saving nearly 120 pounds.
I have a light weight mini starter in my parts collections. It replaces a 25lb factory starter with a 10lb permanent magnet gear reduction starter. Plus the factory starter was never intended to turn over an 11:1 compression stroker engine.
Valves:
I still need to look at the exhaust valves in my old cast iron cylinder heads to see if my lean burn tune was burning up the exhaust valves. If so then I need to buy some high tech more heat resistant exhaust valves.
Less oil:
I am replacing the truck oil pan with a chevelle oil pan.
That means 1 less quart of oil to add each oil change, 1 less quart of oil to warm up, so the engine oil will come up to operating temperature that much faster and there is less chance of damaging the oil pan because it sits about 1 to 1.5 inches higher off the ground.
Clean:
I am putting the engine together on the engine stand in a spare bed room to keep the dirt and moisture out of it compared to assembling it out side and storing it in the garage.