fl327 Posted June 8, 2002 Share Posted June 8, 2002 400 sbc 030. over 10:1 flatops performer alum. heads 292h comp cam hyd. roller hei ignition full length headers 750 holley double pumper what can i expect out of a combo like this as is motor is pretty fresh. Quote Link to comment Share on other sites More sharing options...
Guest 1fastz Posted June 8, 2002 Share Posted June 8, 2002 well to start with a flat top piston with 6 cc head is 11-1 are you heads 72 cc? exspect arouns 420-450 horses at the flywheel Quote Link to comment Share on other sites More sharing options...
pparaska Posted June 9, 2002 Share Posted June 9, 2002 I used Desktop Dyno 2000, with Chevy High Performances flow numbers for those heads. I couldn't find a 292 duration hydraulic roller cam, but I used the 294 hyd Xtreme roller, PN 12-443-8 I assumed a single plane manifold, large tube headers through mufflers Here's what DD2000 said: code: rpm HP torque (ft-lb) 2000 133.0 349.1 2500 179.8 377.7 3000 226.9 397.1 3500 286.2 429.4 4000 347.3 455.8 4500 403.4 470.7 5000 442.9 465.1 5500 463.6 442.5 6000 467.5 409.1 6500 454.4 367.0 7000 416.7 312.5 7500 384.9 269.4 Pretty Stout! Quote Link to comment Share on other sites More sharing options...
Guest 1fastz Posted June 9, 2002 Share Posted June 9, 2002 the 292 is the 292 magnum hydraulic cam and would give up 20 - 30 horses at least vs a 249 extreme energy cam Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted June 9, 2002 Share Posted June 9, 2002 That is some sweet numbers.It is almost the same motor i have in mine Quote Link to comment Share on other sites More sharing options...
Z-Dreamer Posted June 9, 2002 Share Posted June 9, 2002 Sounds like a solid combo Leonard! I'm a bit perplexed though having run countless sims on DD 2000 and the best "streetable" combo I can come up with my existing parts are... 350 Sportsman block 30 over Ported Pontiac MotorSport High Port Heads 2.10 Int./1.625 Exh. Couldn't find flow numbers for these heads, but have been told by serveral race engine builders that they flow as well as any 23 degree race head on the market. So I used AFR's Ported 210cc race heads advertised numbers. It will be a 10:1 motor with Forged Manley Pistons, 6" H-Beam rods, 3.48" Forged Scat crank. 750 CFM Carb Holley 4150 HP or BG Race Demon or possibly the 750 cfm Dominator atop a Super Victor intake. Large-Tube full-length custom Headers, through the mufflers. It's the cam science that confuses me, I don't want too much overlap or I won't be able to idle under 1000 rpm! Too much duration and I won't have any vacuum for brakes! The best I've been able to come up with is a solid roller cam with 282 Int. and 292 Exh. duration advertised with a .560" lift and a 112 LBA. DD 2000 shows 533 Peak HP @ 6500 RPM and 474 ft-lbs. @ 5000 RPM. I'm I doing some thing wrong? Mark Quote Link to comment Share on other sites More sharing options...
pparaska Posted June 9, 2002 Share Posted June 9, 2002 Of course, it's just a computer program, but those numbers don't sound too bad! Probably high, but that kind of power out of a "streetable" 355 seems good! Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted June 9, 2002 Share Posted June 9, 2002 If You have David Vizard's book on "How to Build & Modify Chevy Small Block V8 Cylinder Heads" you can turn to page 145. There you will find in the upper right the flow numbers for the Pontiac-Chevy 23* Heads. I'll go ahead and list them for you here; BTW, these numbers were taken at the Standard Pressure Drop of 25" of water. Pontiac-Chevy 23 Degree #867 Heads Intake Port Volumes were 245cc ____Stock Intake Valve___Larger Intake Valve ........1.94" Valve...........2.05" Valve... .050....26cfm.................31cfm......... .100....57....................62............ .200....105...................128........... .300....153...................187........... .400....179...................236........... .500....180...................263........... .600....188...................281........... .700....192...................296........... *NOTE: The Larger Intake Valve cylinder head was ported for maximum airflow to compliment the larger valves. Exhaust Airflow ___Stock Exhaust Valve___Larger Exhaust Valve ........1.60" Ex.Valve........1.625" Ex.Valve .050....24cfm.................27cfm.......... .100....40....................55............. .200....75....................104............ .300....105...................142............ .400....118...................178............ .500....122...................198............ .600....124...................208............ .700....125...................220............ There you go, hope this helped. BTW: I know one of my books has a HOT ROD comparison of 4 different Comp Cam's on a healthy 355. Once I find it I'll post their actual numbers on this thread. Till then, here are the airflow numbers for your Pontiac-Chevy 23* SBC heads. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted June 10, 2002 Share Posted June 10, 2002 Okay, found the Hot Rod tests. My notes indicate two different articles whereby Hot Rod used the same SBC 355, 9.7:1 SCR (Static Compression Ratio), 190cc AFR Alluminum heads w/Fed.Mogal LW-2256 Pistons-whatever those are(?). The 9.7:1 SCR indicates a total chamber volume of 83.58cc's. The first article tested Flat Tappet Hydraulic Cams only, four of them to be exact. While the Second article tested a 294HR (Hydraulic Roller). This article didnt offer idle quaulity; but hey, if you're planning on a 294 anything cam then idle isnt really a concern ; if idle is a concern then you should think about a milder cam . Before I give the results of the articles, I'ld like to throw out my .02c's worth; and that would be concerning your low rpm idle you mentioned earlier. The overlap figure is equally as important but IMHO the actual cam event you should look for is the IVC. For it is the IVC (Intake Valve Closing) that determines DCR (Dynamic Compression Ratio) while the overlap is important for low valve lift airlfow figures. Some may argue Duration -vs- Overlap is the "Chicken and the Egg" argument in that; which came first Overlap or Duration? Nonetheless, the piston's location in the cylinder relative to IVC determines the quality of your low rpm idle; and what your DCR will be. From all the reading I've done it appears an 8.5:1 DCR for a street engine on pump gas will give a nice 600-750rpm idle while anything falling away from the 8.5:1 DCR will compromise that rule. As you get further & further away from the 8.5:1 DCR rule you are getting closer and closer to detonation which requires a higher octane fuel; also requiring race gas. Alluminum helps the street engines on pump gas get away with a little less DCR without detonation; but your low rpm idle still suffers. Here are the results: Comp Cam 1)252H: IVC @ 52*'s with .856% Cylinder Volume Reamaining = 8.45:1 DCR: idled @ 600rpm's w/18"Hg.Vacuum; Peak 398tq @ 3900rpm's/347hp @ 5100rpm's 2)268H: IVC @ 60*'s with .808% Cyl.Vol.Remaining = 8.03:1 DCR: idled @ 800rpm's w/16"Hg.Vacuum; Peak 401tq @ 4100rpm's / 380hp @ 5500rpm's (Noticeable Choppy Idle) 3)280H: IVC @ 66*'s with .768% Cyl.Vol.Remaining = 7.69:1 DCR: idled @ 850rpm's w/12"Hg.Vacuum; Peak 403tq @ 4300rpm's / 404hp @ 5700rpm's (Definate Choppy Idle) 4)292H: IVC @ 72*'s with .725% Cyl.Vol.Remaining = 7.31:1 DCR: idled @ 850-900rpm's w/8"Hg.Vacuum; Peak 399tq @ 4500rpm's / 430hp @ 6700rpm's (Very Wavy Choppy Idle) These next cam came from the second article and did not give their idle characteristics. 5)294HR: IVC @ 73*'s with .717% Cyl.Vol.Remaining = 7.24:1 DCR: Peak 436tq @ 5500rpm's / 477hp @ 7100rpm's Notice the difference between the #4 Flat Tappet Hyd.Cam -vs- the difference in #5 Hydraulic Roller. It definately free'd up some hp and torque. Also notice how close the real numbers are compared to Pete's DD numbers? The difference would definately be in the restrictive exhaust manifolds -vs- a non-restrictive appropriate and optimum set of headers; which we all know in our V8z's we have to compromise in that area. This brings up a good point; why build a "killer" engine only to be forced in to "choking" it with less than preimuim headers due to space limitations. Unless you plan on fabricating the engine bay area to allow for better headers; less in this instance may be better than more! Good thread; I always enjoy the "possibility of power from an engine not yet built" type of conversations. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Z-Dreamer Posted June 10, 2002 Share Posted June 10, 2002 Kevin, thanks for the Pontiac MotorSport head flow numbers! I punched them into DD 2000 and used my 2.10 Int. valve size and porting into account and now have new figures: Using a 282*Int. 292*Exh. advertised and a .560" lift with a 112 LBA. I get 548 HP @ 6500 RPM and 480ft-lbs. @ 5000 RPM. IVC @ 69*, valve overlap 63*. Better, but I'm thinking it might be better to drop the LBA to say 108* and the duration down to 278 accross the board? I want to keep the idle under 900 rpm's. Any suggustions? Anybody? Mark Quote Link to comment Share on other sites More sharing options...
fl327 Posted June 10, 2002 Author Share Posted June 10, 2002 oh man didnt think it would be a ground pounder like that, it will be a while before it starts, but oh dang. sorry cant be more specific, im just hoping for upper 300s to the wheels and lot of tork. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted June 12, 2002 Share Posted June 12, 2002 Is this a daily driver, weekend warrior or dedicated drag strip car? Are you using stock piston compression heights, stock connecting rod lengths and a stock block deck height? If so, what rpm are you wanting; just anything under 900rpm's? Total Displacement in relation to Static Compression and Dynamic Compression will determine the duration of your cam. While the Cylinder Head's Limiting Port Volume at the Intake Port's opening will determine your "Potential" peak power and "Potential" peak rpm's, providing your intake delivery system and exhaust system are optimal; all this has an effect on the airflow capability of that cylinder head. Bottem line is going to be the intention of the car and what low rpm idle quality you are willing to live with in the confines of Daily Driver, Weekend Warrior or Dedicated Dragster/Racer. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Z-Dreamer Posted June 12, 2002 Share Posted June 12, 2002 This will be a fair weather weekend machine. Made to handle but capable of 10 second quarter miles. The intake will be a Super Victor and a 750 CFM something. The exhaust will consist of custom big-tube headers and free-flow exhaust system. It will also be a stick-shift car with a 3.70-4.10 geared IRS. Mark Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted June 13, 2002 Share Posted June 13, 2002 If its a weekend warrior "made to handle" just be sure its a manual tranny with that cam of choice. Have you checked the archives about headers; I seem to remember that a problem exists with area limitations in the Header dept; your operative word "Custom" is definately in order if you plan on the engine w/that cam. Good luck! Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
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