by rustbucket79 » Thu Jul 26, 2012 1:22 am
A cut and paste of my results from another website. Your 60' times and ET/MPH are soft IMHO. (N/A, I have no opinion on your nitrous results) You could have a tuning issue, a mismatch issue, or weak heads.
The car:
79 Camaro, Moroso trick springs up front, Calvert split mono's out back, Koni SPA-1's all around, Cal Trac bars set at zero, 9x29.5 M/T slicks, 10 bolt diff with spool, 6 point roll bar, some lightening done to the car, fuel cell, Holley black pump, etc.
The old combo:
850 Holley double pumper, ported Vic Jr, with 1" 4 hole on top of 1" open phenolic spacers, ported GM iron Bowtie heads (phase 2), Scat H beams, Scat Superlight 3.75 crank, Wiseco 10 cc domes, (14.4:1 static) custom Tim Cole spec'd Comp solid roller, .450"/.435" lobe, 7/4 swap, 109 lobe separation, 26x/27x duration, Speed Pro 1.5 roller rockers, crank scraper, diamond stripper windage tray, 5W-20 Royal Purple, 1 3/4 Hooker Super Comp headers with evac u pan setup, oh and a factory GM 400 block filled, zero decked, steel caps installed, and eventually split on the passenger side 1" below the deck. 3" dual exhaust with H pipe and 3 chamber Flowmasters. Speed Pro file fits with low tension oil rings.
Ran 10.7's at my local track with 90# of ballast, TH350 footbraked, 5300 flash on the playback tach. Ran mid 10.5's with the exhaust system removed, ballast removed, measured 3220 pounds with driver, race ready. Best 60' time of a 1.422 using 4.56 gears. VP 113 fuel.
The new combo:
Same carb, same intake setup, AFR 245's (70 cc chamber models) entirely untouched other than disassembly and inspection, spring pressure and clearance checks, (sub 13:1 compression), etc, same rotator, same cam, Dart Little M block with same prep, Keith Jones spec'd gap style ring package (napier second/8 pound oil ring), same crank scraper, Milodon kickout oil pan with built in windage tray (31167 IIRC), 15W-40 conventional oil, same headers and exhaust, T & D shaft rockers 1.7/1.6 ratio, same 3/8" diameter 7.900 Comp Hi Tech pushrods as last combo (glad there was one minor expense I didn't have to incur)
Best run, 34 degrees timing (no testing done to see if it wants less or more) at 3800' as per my Performaire Eclipse weather station, 3300 pounds race weight, through the same exhaust, at a different track than the previous passes, lower elevation (but the local ET's with a crap 60' time look promising), TH400 with brake, same converter which now flashes 6000 but a 4.10 rear gear to replace the cracked 4.56's:
1.373 60' time
4.102 330 time
6.388 660 time
107.38 MPH
8.378 1000 time
10.064 1320 time
133.57 MPH
All in all, the heads pretty much make this engine an animal, it likes RPM despite the smallish duration (compared to what some run), and even though the intake runners are nearly 50 cc's larger than the previous heads and the compression is 1.5 points less, the flash speed of the stall shows this combo makes a boatload more torque than the previous combo, and it doesn't mind the higher rear gear ratio. (it crosses the finish line at the same RPM as last year, 6900)
I still have tuning to do, would like to try a 4.30 or 4.56 rear gear, still have a 2970 intake to be ported and installed along with a 1050 dominator, would like to try open exhaust, larger headers, etc. Anyone looking to build this level of engine I would highly recommend these heads, they are a great value for the money, and they make great HP.
