Impala SS 396 Engine Project
The plan is to put together a combination that produces somewhere in the 500+ horsepower range that can be driven anywhere. With decent traction, I expect the car to run mid 12's at well over 110 mph. That ought to get the attention of those people in 'other' performance cars out in the street. Even Vipers and 911 Turbos. The first time I get beat with the new engine, I will proceed directly to the next paragraph and finish the job. Well, finish is sort of a realtive term. Can a project like this ever really be considered done? I think not.
Once the original combination gets sorted out, set up and is running well, I am going to be plumbing a full blown port injected 8-nozzle in your face nitrous system. That's why the bottom end is so beefy. What we are working on is actually two separate systems that will work independantly of each other. The main system will be a hidden under the manifold Nitrous Express fogger system with Pirhana nozzles. This can be tuned anywhere from 150 hp to about 600 if I was really greedy. Gives me a choice of about 4 levels of power with the flip of a switch...talk about Jekyl and Hyde.
There is a new picture section. I didn't want to bog down the loading of this page with graphics, so I stuck them all on another page. It loads pretty slow, so you might want to start it up in another window. In Netscape, just right-click and select 'Open in new window' here.
UPDATE: The project is currently on hold. I took the running diary down since there hasn't been anything to show since March. Steve Morris has been fiddling with the heads on and off in his spare time since he got that new SuperFlow 1020 to test them on. The lastest news is that they are likely getting the intake floors raised. He wants to start testing the raised port to see how it responds on the bigger flowbench. I'm going to try and talk him into emailing me a flow file so I can post them on this site. Stay tuned...
Specifications:
- Block: Production LT1 from a '94 Mi State Trooper Car (see this battered beast here and here). Lifter valley oil center returns plugged and end drainbacks opened and smoothed. Fully deburred, shot-peened and bottom tapped. All oil passage corners and edges rounded for smooth oil flow. Dorman HPX tapered brass freeze plugs. Machine work will involve line-boring and honing the main saddles after the installation of the billet caps, squaring and setting deck height, bore and hone on fixture to set bore centers, and correctly index bushed lifter bores.
- Heads: AFR CNC LT1 replacements that are derivative of their L98 head effort. These heads are very trick with .750" thick decks and chambers. They came with CNC ported chambers, exhaust ports and intake bowls. The valve sizes are 2.020 intake and 1.600 exhaust and come with titanium 10 degree retainers and double springs with dampers. They have been milled to make the chambers 64cc to produce 11.0:1 compression ratio. The ports are far too small for the engine and associated power that it will need to produce, so they are getting reshaped in a big way. In fact, the port volumes are growing to the tune of 15%. So far Steve Morris has found 50cfm more flow on the intake side and is not really even finished with them. They are gonna be awesome.
- Induction: Initially, I am putting on a heavily modified LT1 intake with 58mm throttlebody. I don't expect this system to remain on the car very long (see future mods).
- Camshaft: Either Lingenfelter 74211 (210o/218o@.050" and .533"/.560" lift with 1.6:1 rockers) or one of two custom CompCams grinds that we will be testing on the dyno.
- Lifters: Crower billet body hydraulic roller.
- Rocker Arms: Jesel 1.6:1 shaft rocker system with .450" offset intake rockers to clear the ports. This gives enough room to straighten out the port for correct volume and flow.
- Pistons: JE 4.030" bore with 1.217" compression height and no dish. PolyDyn ceramic thermal barrier top and dry film lubricant skirt coatings.
- Wristpins: JE 0.927"x2.950" Type 51S. Held in with double spiro-locs.
- Rings: Speed Pro file fit standard high performance set.
- Rods: Oliver billet 4340 5.850" long with floating pin bushings.
- Crankshaft: Callies 4340 non-twisted forging with 3.875" stroke and 350 journals. Internally balanced and drilled connecting rod throws.
- Main Caps: Oliver billet 4340 splayed flat bottom 4-bolt center caps, and standard configuration end caps.
- Main Studs: ARP 234-5601.
- Head Studs: ARP 234-4601. I like these because they have 12pt nuts and necked down short studs to produce more even clamping pressure on the head gasket.
- Main Bearings: Clevite 77 H-series.
- Rod Bearings: Clevite 77 H-series.
- Timing Chain: GMPP 1/2" pitch roller high performance replacement for LT4.
- Pushrods: Undecided.
- Oil Pump: Moroso 22100 anti-cavitation pump with ARP 230-7002 stud and ARP 134-7901 driveshaft.
- Oil Pan: Heavily modified original pan.
- Head Gaskets: FelPro 1074.
- Exhaust: Grotyohann Motorsports full length headers and Borla cat-back.
- Fuel Injectors: TBD.
- Fuel Injection: SpeedPro ECU (previously known as FP Performance SEFI8LO) system that is piggybacked to the PCM by a Bothwell Automotive LYNKX interface module. This is a pretty trick piece that processes the OptiSpark signal and feeds it in a useable form to the SEFI8LO so it can run in sequential mode.
- Nitrous: Two seperate 8 nozzle dry flow systems under the manifold. The nice part about using the SpeedPro ECU is that two stages of dry flow nitrous are supported meaning that I can just plumb in nitrous nozzles and the timing and fuel requirements are handled by the computer. Should make for a very easy to tune system that is capable of a lot of power. The system started life as a NOS cheater with individual nozzles for fuel and nitrous.
Future Modifications:
- Intake Manifold: Heavy experimentation area. May try Accel SuperRam or other aftermarket piece. I'm sure that in a year, there will be a few more offerings to choose from.
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Scott Knight