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11-13-2008 05:50 PM #10
Thanks guys!
JR - The chrome looking parts are ceramic coated. I don't know if anyone does powder coating in that color.
The engine is pretty much together now. When the chassis is complete, I plan to run the engine before bolting on the body to check for leaks or other problems. The brakes will be bled and functional, too.
The specs on the motor wound up a little different than I had originally planned. I never did come up with a usable pair of Vortec heads. Actually, I gave up because I got tired of driving 40 miles to the wrecking yard and then paying the machine shop to check them for cracks. I already had a set of "camel hump" heads that had a good bit of work on them. They have 7/16" screw in studs, big valve springs, one piece stainless valves(2.02 and 1.6) and the guides have been cut for better seals. In addition, they have had some port and bowl work done. These are the older style with no accessory holes, but that doesn't matter because I don't need them. They don't have the "fast burn" combustion chamber of the Vortecs, but they should do OK on this motor. If this was 1970, they would be a killer set of heads though!
The bottom end is stock Vortec. It's interesting that GM used a lot of "hot rod" tech in these late model small blocks. I had heard that the rotating assemblies are supposed to be lighter due to the "forged powdered metal" rods as well as lighter pistons. Out of curiosity, I wieghed an old style piston/rod assembly and one from the Vortec. The old stuff was 2.7 ounces heavier than the new. I was told the crank is about the same weight as an old style 305 unit. The rings are thinner than the old small blocks, too, which should reduce friction loses. It even has a small windage tray. I also went with a 6" light weight balancer instead of the 8" stock unit to eleminate clearance issues with the front crossmember. The lighter balancer should allow it to rev quicker, too. Since the stock Vortec heads and the ones I'm using both have 64cc chambers the CR should be unchanged at around 9.2 to 1. That's the only downside since I may have to run premium gas.
The cam is a GM "Ramjet 350" unit from their 350 HP EFI crate motor. It's a pretty tame cam by hot rod standards with 196/206 @ .050 duration, but it has decent lift at .450 intake and .487 exhaust with 1.6 rockers. Those duration figures are close to the old 300 HP 327 cam, but with it's much greater lift it should be a little more aggressive than the old 327 cam. It also has a tighter lobe seperation at 109 degrees. I went with 1.6 rockers because that is what GM uses in the Ramjet. I doubt I'll be getting 350 HP out of this engine with the old style heads, but my original goal was 300 and I'm pretty sure I'll be over that with room to spare. Low end and mid-range torque should be great and this cam should work well with the OD trans. Since my engine speed at 60 MPH should be in the 1800 RPM range, I'm expecting gas mileage to be excellent.
The intake setup is an Edelbrock 3X2 with Rochester 2 barrels. The carbs were redone by Hot Rod Carburetion with their linkage and fuel line. I modified the manifold for a semi-hidden PCV setup. I had a similar rig on my 46, but had to abandon it because it sucked oil. That old setup didn't have an oil baffel underneath. The new one does so it should work OK(I hope). The old style oil fill on the intake has a breather cap, but that may not be enough vent, if it's not I can add Moon style breathers to the valve covers. The Stellings and Helling(copies)"helmet" type air filters look good, but I may have to change them out as they appear to be pretty restrictive. The 4" filters are restrictive by themselves and the helmet cover fits very close to the filter element, probably choking it off even more. I may go with some finned aluminun open filters from Obrien Truckers or Vintage Speed.
The ignition is MSD and I plan to trigger the box with a point type distributor. The 3X2 requires a small base distributor and I picked up an Accel Blueprint unit on Ebay, but I had to change the gear to a "melonized"(that's actually what they call it!) gear from GM. That's just a hardened steel gear that's compatible with the steel roller cams used by GM. By using points to fire the MSD unit, I have the option of swapping over to regular point ignition if the box fails. All I need is a resistor in the coil circuit and a quick "rewire" of the coil.
The plug wires are still unfinished. I want to run them under the headers, but they may interfere with the steering shaft. I hope not, since I really don't want to go over the top.
I must say that this engine build is a lot different than any other I've done. Since this one will be totaly uncovered, I have taken extra time to assemble and detail it. I can usually knock out an engine in a couple of days, but this time I tinkered around on little details off and on for several days till I was satisfied with the way it looked.
I tried to give the engine an old school look to go with the overall look of the car. I could probably pass it off as a 327 to most folks if I wanted to, but I won't since I don't have any problems with the "belly button 350" thing.
I saw last night on fb about John. The world sure lost a great one. I'm going to miss his humor, advice, and perspective from another portion of the world. Rest in Peace Johnboy.
John Norton aka johnboy