Corzette Posted February 1, 2003 Share Posted February 1, 2003 Grumpy if you are out there can you please help out a distant friend! I have finally got my car out of paint and it can be seen under the paint album below. I plan on building the 450 HP setup on AFRs site. This is what I have so far... 350 .040 over Scat 350 crank 3.48 5.7 Eagle rods KB106 Flat Tops Comp Cams XR282HR-10 Part Number 12-432-8 Grind Number CS XR282HR-10 Description Intake Exhaust Valve Adjustment 0 0 Gross Valve Lift 0.51 0.52 Duration At 0.006 Tappet Lift 282 288 Valve Timing At 0.006 Open Close Intake 35 67 Exhaust 78 30 These Specs Are For The Cam Installed At 106 Intake CL Intake Exhaust Duration At 0.05 230 236 Lobe Lift 0.34 0.347 Lobe Separation 110 I want to run a holley 750 DP Hooker Block Huggers 2 1/2 Duals to X pipe and out etc. I want to get the AFR intake that they recommend I want to get the AFR 190 heads I will have 3:54 rear gears 700R4 with 2800 stall Do you think the AFR 195s will do a better job or should I stay with the 190s. Is there a better intake selection? I have already bought everything except the heads, intake, and carb. Grumpy I need your advice before I buy the rest of these parts...which would be the best bet. Afr says 450HP from their specs?????? CorZette Quote Link to comment Share on other sites More sharing options...
Corzette Posted February 2, 2003 Author Share Posted February 2, 2003 Grumpy, I am a little confused. The book says the Compression Ratio should be around 9:5:1. When you say dynamic are you talking about the actual CR? Man 7:6:1 would be a dog. Do you think AFR makes a 62CC Head? Do you know any others that flow as well as AFR that may have a 64CC chamber? I am looking for around 9:5:1 - 10:1 ratio. Man its a good thing I asked you about....My pistons are the KB106 flattop type. My cam is a retrofit so cam rod clearances are not a problem. It all rotates freely.. CZ Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted February 2, 2003 Share Posted February 2, 2003 I believe Grumpy is talking about dynamic compression which is lower than your cr #'s due to the cams duration being 230/236 at .50. If you run a big cam you need to bump up the compression to deal with the bleed off. I was using the kb hypers at 9.7 to 1 with 64cc heads but with a bigger cam I used thinner head gaskets to get closer to 10.5 to 1 compression. I also run 93 octane as Texas still offers it. I was unhappy with my cams 238/244 duration at .50 so went to a hydraulic roller with 224/230 duration and a dual plain intake and I love it. Still plenty of lump to it! I am running a Holley 750 dp'er and like it with exception to fuel economy or lack of but what the heck I like it better than my 750 Edelbrock. Good luck with what ever you decide to do just keep us noisy people up to date. Mike Quote Link to comment Share on other sites More sharing options...
Corzette Posted February 2, 2003 Author Share Posted February 2, 2003 This is what I get with the calculator: Cylinder Head Volume (cc) 68 Piston Head Volume (cc) 7 Gasket Thickness (in.) .038 Gasket Bore (in.) 4.060 Cylinder Bore Diameter (in.) 4.040 Deck Clearance (in.) 0.00 Stroke (in.) 3.48 COMPRESSION RATIO 09.804 If I use the Gasket bore of 4.060 vice 4.125 I get a little higher CR as well. How do these numbers look Grumpy? I think I will stay with the AFR 190s. Do you think this build would put out anything close to 450HP? Seems a little high to me... CZ Quote Link to comment Share on other sites More sharing options...
Corzette Posted February 2, 2003 Author Share Posted February 2, 2003 By the way I have a few new paint pics of the car...more to come. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted February 2, 2003 Share Posted February 2, 2003 yes your static compression ratio is about 9.7-to 9.8 but thats not what the engine sees, remember the pistons compress NOTHING UNTILL THE VALVE CLOSE! here some good reading http://members.uia.net/pkelley2/DynamicCR.html Quote Link to comment Share on other sites More sharing options...
Corzette Posted February 2, 2003 Author Share Posted February 2, 2003 Roger that, I understand. I used the calculator and I get around 7:7:1 ratio. You said I was slightly off....what would be a good target to shoot for? Say 8:1:1 or so? If I go with what I have now would I be giving up alot of power? Sorry so many questions but I want to do it right the first time. You are the motor GOD you know! I was thinking about maybe 64 cc heads to be in between but AFR doesnt make those I dont think.... Terry Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted February 2, 2003 Share Posted February 2, 2003 theres little if any differance between the AFR 190cc and AFR 195cc heads, other than the intake port gasket surface port size, Id get the 195cc size and have them mill about 10-15 thousands off to lower the combustion chamber size slightly, you have almost everything correct,but even with the 68cc head your dynamic compression will be slightly low with that cam, at about 7.6:1 so use the thinnest head gasket that gets you about a .038-.041 quench and very carefully check pistion to valve clearances and rod to cam clearances and if you order the heads with a 62-62 cc combustion chamber the engine will make more power but limit you to high test gas at all times, IF you have access to 93 octane gas,if you don,t have 93 octane ALL THE TIME, leave the heads at 68cc if you don,t have a steady supply of good gas! BTW that cam is very similar to the one Im running in my 383 http://dab7.cranecams.com/SpecCard/DisplayCatalogCard.asp?PN=119661&B1=Display+Card which I picked for its greater lift and smoother idle mostly due to the wider 112 LSA that makes it a better NITROUS cam even though your cars light I think youll be slightly better off useing a EDELBROCK AIRGAP RPM INTAKE for massive mid-range torque and a vacuum secondary 750-780cfb carb, DP carbs work well when used at the track where your foots on the floor most of the time but if you intend to drive on the street get the airgap/RPM and vacuum secondary carb, youll be much happier!!! Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted February 2, 2003 Share Posted February 2, 2003 8.2 :1 is what Id be trying for with a set of aluminum heads, now the differance in hp is about 4% for every step up in compression example at 9:1 if the engine makes 400hp at 10:1 its likely with no other changes to make about 416hp now Ill grant you thats not what looks like a huge increase but that 16hp is over the whole rpm range not just the peak. and since your buying pistons you might as well get the best cpr pistons you can because theres very little cost differance. keep in mind milling the heads slightly to lower the combustion chamber voluum and useing a thinner head gasket are also options.in your case just changeing to a slightly thinner head gasket and a minimal head mill of about .015 thousands will get you there. but talk to AFR like I said before the differance is minor and might not really be worth worring about if a few hp and a few ft lbs of tq are not worth the costs involved. what Im trying to get accross is that its the little things that add up!its the minor changes made durring the planing and assembly phase that make the differances! heres a few examples your dynamic compression ratio is what matters and thats to a large part determined by the relationship between the static compression ratio and your cam timeing at 9:1 static cpr if the engine makes 400hp at 10:1 static cpr its likely with no other changes to make about 416hp now Ill grant you thats not what looks like a huge increase but that 16hp is over almost the whole rpm range not just the peak. and since your buying pistons you might as well get the best cpr pistons you can because theres very little cost differance. keep in mind milling the heads slightly to lower the combustion chamber voluum and useing a thinner head gasket are also options. just changeing to a slightly thinner head gasket and a minimal head mill of about .015 thousands will sometimes get you there. getting the quench into the .035-.042 area of clearance, useing oil retaining piston skirt coatings,ETC. but talk to your head and cam manufacturers like I said before the differance are minor and might not really be worth worring about if a few hp and a few ft lbs of tq are not worth the costs involved to you but the differances add up! what Im trying to get accross is that the differance between a very good engine combo and a great engine combo is the slight differances made, its the 50hp you get from useing great flowing heads verus the stock heads its the 40hp you get with a stroker crank assembly versus the stock displacement its the 30 extra hp you get by correctly picking a perfect cam verus useing the hot cam your buddy suggested without checking if it truely matches YOUR COMBO its the 3-7 hp get from ballancing the engine assembly, the 5-7hp youll at least at high rpm get by running longer connecting rods,its the 3hp from perfectly fitting pistons versus too much clearance and the 7 hp from a cam thats advanced or retarded to get the most out of it, and the 15hp you get by getting your cpr exactly where you want it and the 4hp you get with synthetic versus mineral oil, and the 3hp you get by gapping your rings correctly, its the 5hp you get by port matching and the 20hp you get by smoothing and blending the bowl and chamber areas, its the 12 hp you get by useing long tube headers versus short tubes and the 15 hp you get by useing a merge collector with a full length free flow exhaust versus a standard collector and stock exhaust its the 3hp that you get from running the correct fuel pressure. the 5hp you get with a windage tray the 8hp you get from a good free flow air filter ETC. as examples, that combined make the differance, not some special super part you installed, ITS THE SMALL DIFFERANCES THAT ADD UP! Quote Link to comment Share on other sites More sharing options...
Corzette Posted February 3, 2003 Author Share Posted February 3, 2003 Man Grumpy thanks for taking the time to post that...sounds like the secret ingredients to a winning combo. My next engine will be a 383 or 406 for sure. Ill see if they can mill the heads .015 before shipping and use a .038 with 4.150 or so bore gasket.... CZ Quote Link to comment Share on other sites More sharing options...
Corzette Posted February 3, 2003 Author Share Posted February 3, 2003 Grumpy, I found a gasket that is .015 compressed and has a bore of 4.100. Plugging into the chart gives me a 8.11 SCR. Provided my valves dont hit the pistons, is .015 quench OK? CZ Quote Link to comment Share on other sites More sharing options...
Corzette Posted February 3, 2003 Author Share Posted February 3, 2003 That gasket is part# 375-1094 Embossed shim out of Jegs (Felpro)...would that work? That is a head gasket and not just a shim right? CZ Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted February 3, 2003 Share Posted February 3, 2003 no! you must keep the quench in the .035->.042 thousands range for clearance, pistons/rod stretch at high rpms enough that anything less that about .028 thousands tends to cause big problems Quote Link to comment Share on other sites More sharing options...
Corzette Posted February 3, 2003 Author Share Posted February 3, 2003 Understood...thanks! Quote Link to comment Share on other sites More sharing options...
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