I would say that these two cams are a world apart with yours Orr having a better spec from a pure performance point of view. I imagine tuning it wasn't all that much of a threat to you either. How did it drive street-wise? Any indication of your fuel economy on the highway? FWIW, I take that last stat as importantly as I do HP. I drive my vehicles. A lot. And I don't want to end up in the poor house because of it.

 

Looking through COMPs lobe catalogue I found a 232 and 236 spec in the XFI section. Works out to 282 and 286 advertised respectively.
Not sure how the Vette guy got to 11.2:1. Best I can calculate with 65cc heads, 5cc piston, zero deck and .040" gasket is 11:1 flat. With a 11:1 SCR, that cam with a 112 LSA and 108 ICL results in a DCR of 8.5:1 with an overlap of 60 degrees. If I fudge the numbers a little 11.2:1 gets 8.7:1. Not sure how pump gas friendly that would be.
But regardless of your take on DCR in general, that's a pretty stout number. I'd say it's a safe bet that it contributed to that level of output.
I'd try and do the same with yours Orr but I don't enough details. (Couldn't find a 245 lobe in any of the usual categories.)

 

idle was abit finicky at first as i was trying to keep it closed loop, but also it was hunting and surging at times. Once i got fuel right and timing table adjusted correctly it calmed down well. Driving was smooth and fine. I could lock converter at 25-30 mph up a hill and pull effortlessly. Idk what gas mileage was but i felt it was respectable. Between 10 and 20 lol it wasnt as good as my L98 was stock nor my bolt on LS1 but better than my turbo stuff which got closer to 10 lol. This was mixed average mostly short drives with stop and go. Never much of a long highway cruiser. I may have tuned better for that and got something decent but car was too fun to drive hard.

My cam was a custom grind thru comp, actual specs are very close to the magnum high lift lobes, but actual specs are 286 adv intake 306 adv exhaust. .377/.383 lobe lifts. Lot more duration split than i figured it needed but it did get a 150 shot added so it seemed to be ok with it

also note the lobe specs in the catalog are guidelines, but depending on cam core size and base circle the actual specs can grow a deg or so and some minor lift changes. My bbc cam spec grew .002” lift and 1 deg at .050” on the bbc core. A sbc core with same lobe spec number may be 1-2 deg diff from that

 

All,
I know it’s been a while but I promised an update. Sadly not much real progress with engine. Since last post I’ve installed body harness and all lighting, bumpers, grills and trim. On interior I’ve done carpet, dash/instrument wiring, all new Al Khoch dash panels, and new parking brake and center console. CCS head unit and 2 4x6 front / 2 6x9 rear with 10 inch down drive sub and 600w amp. All are Kicker through CCS. The stereo, gauges and completion of Vintage Air controls added a bit of time to the interior work. The tach has been converted to electronic and speedo is cable driven off of TKO trans. All other gauges signaled directly off of stock type senders. The seats are Fiero in Mr Mike’s corvette pattern. I still have to get new side windows and door panels to complete interior.

For power train I’ve completed the HP EFI harness install and added relays for in tank Walbro 255 lph pump, ECU, CNP Ignition and Nitrous system. The nitrous is set/ready for external pump plumbed off of sender feed line, single wet stage and purge solenoid. Center console has activation switches for ECU and external pump plus momentary switch for purge and toggle for fan override. I know this sounds busy but the center console came out really nice; like it could have been factory.

For the engine. I’ve decided to stick with the 195 Street Eliminators and 280XFI cam. More than anything, it’s just such a substantial project and it’s time to get it on the road. The side mount headers just barely fit through the chassis tubes so even minute exh port height changes are problematic and a cam change is more than I want to do at this point. With that said, I want to make the most of the combo. Something I never mentioned before is that my fuel delivery system is -6 and only sized for 550hp. Injectors are Holley 36 lb/hr.

Heads will stay stock port for now but are removed to mill .030 for 60cc. This should yield 10.2-10.3:1 scr with .030 gasket and give about .033 to .035 quench. The Victor E EFI intake has been opened up at top to match the zex perimeter plate/throttle body and lightly cleaned up in plenum and runners. Once the heads are back on I’ll port match to heads. Fuel delivery plumbed to new intake with Holley FPR. I mentioned the CNP with the harness install but the details on that are Holley sub harnesses to Holley Smart Coils. Preferred mock up was 4 coils mounted into packs and each pack mounted on inside edge and centered longitudinally on valve cover. This setup looks really cool with the polished valve covers and round air cleaner. Distributor is Holley Dual Synch with the little flat cap and is ECU timing reference only (plus tach signal).

I’ve been racking my brain and reading up a top on valvetrains; again trying to make the most of what I’ve got. Looking for advice to optimize, not bang for buck. If I ever change from this heads/cam combo it’ll be bigger heads and solid street roller so I figure lets see what the current cam can do. 6500 RPM limit.

I know it’s total overkill but I will be getting Crower Shaft steel rockers. They’re #74139F for the Eliminator heads and I think .250/.080 offsets. I’ve never had shaft rockers. I want their simplicity and I want the most ideal geometry and stability.

For lifters, everything so far points to Johnson 2112r; maybe tie bar, maybe drop in? Actually thinking drop ins because they’re lighter and the lobes are only .360. A goal will be 3/8 pushrods so I plan to mock the rockers with current GMPP lifters before going further.

For springs, sources say the 8017s won’t cut it and the 8019s will be great for performance but I’m concerned about pressures on the cast SADI core. The 8019 shimmed .050 for 1.750 and approx .095 from bind yield approx 170 seat and 435 open. Maybe borrowed time with those and defeats my goals for the car. I’m really interested in the PSI LS1511ML beehive. The beehives are 1.290 OD with .630 ID up top and 130@1.8 / 370@1.175 with 384/in and 1.1 CB; shimmed .050 I get 150@1.750 / 370@1.175 with a closer stack to CB than 8019s and still within the recommended compression specs. And I think they should drop into the existing cups? Brian Tooley has SR007 Ti retainers for .630 ID valve and 7 degree locks. Think I’m on the right path?

I know this is long winded and apologize for that. I’ve been meaning to update for few weeks so here it is all at once.

r,
Rob