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Old 05-08-17, 03:20PM   #1
keith
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Default Kool-aid Keith's 71 Formula 440

Well my engine is moving forward with a forged Scat 4.0 stroke crankshaft vs the modified factory crank I had originally desired. Will still use factory heads vs aluminum as this is not meant to be a race only application. I wanted durability and a tangible performance gain in an engine I could use on the street mostly and possibly modify in the future without taking the shortblock apart. I think factory heads can be modified to put the block right up to the danger zone hp wise and since Im using a factory-alike Nunzi 068 HL flat tappet cam may mesh better for a fun to drive non-quirky street application. Im hoping the enhancements I made to the shortblock and valvetrain will allow the engine to build power to 6500rpm and be somewhat safe operating there with the 4.0 stroke.

All elements of r/a and valvetrain cryo'd by Carter Cryo - r/a balanced by Paul as well

Short block
ARP studs, main caps shotpeened, redoweled with beefier dowels found here
Forged Ross 412F flats - piston tops rod,main,cam brgs Calico'd coated
CAT 3-d 4340 6.900 H-beam ARP 8740 cap
Forged Scat 4.0 crank
Romac balancer wi aluminum outer, Romac timing set
60 psi oil pump and hardenened driveshaft cryo'd

Heads - valvetrain
7mm Ti valves 2.16 in 1.65 ex
CC roller tip rockers 1.65 and 1.52 sets (initially)
Howards 98114 inverted cone springs-locks
Looking for best flowing 90cc head 73 46, 75 6x or 67 670 possibly converted to open chamber(thinking better short turn). I have these. 670 would require most work.

My first induction system will most likely be 2 4360's on an Offy DQ low-rise. Will rebuild and get the 4360s working on my 400 enduro car singly. I like the straight runners on the "Equa-flow" intake and have a buddy who is expert at DQ linkage setup. If its going to make power to 6500 Im thinking that being right will be key. Will most likely need to port the heads to higher flow levels as well. Thinking 1.65 lift for ported heads 1.5 for unported will probably mesh best with cam, but just a guess.

Wanted 0 deck but looks like I will have to settle for -.020 since blocked is decked to 10.220 and my stack up = 10.200 (6.9+1.3+2.0). I had installed .020 undersized rod bearings to gain more room to stroke a factory crank as I had wanted a 4.040 stroke, Scat Pontiac 4.0 cranks only come in BBC rod journal so no extra .050. 440 vs 444 I liked to say Formula 444 dagnabit.
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Old 05-08-17, 09:16PM   #2
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HP is in the heads,that cam will be done pretty much at 5800 with any intake.JMO,Tom
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Old 05-09-17, 01:26AM   #3
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068 cam, pretty much old tri power cam. 350-370 hp with your combo.
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Old 05-10-17, 02:33AM   #4
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068 cam, pretty much old tri power cam. 350-370 hp with your combo.
You may be right, hope I'm able to dyno. My factory 428 was rated at 390 hp, probably with the factory version 068 and 670 heads. I tried for modest improvements in every area of 10-20% including displacement and main size so I'm not sure the hp would be less unless I really boobed somewhere. Like Tom said hp is in the heads, so the better they flow, the faster I go. The factory version of the cam was used in all displacemts I believe. This one is 10% more lift 1.5 20% 1.65 , larger intake valve skinnier stems half weight valves may accelerate faster. My ra stack weight is 11+% lighter 1530 gm vs 1780 stock 400 as measured on my cheapy scale. The 4360s are rated at 450 cfm each but Holley book says they actually outflow a 750 q-jet. Time will tell I guess if my soup is tasty or no.
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Old 05-10-17, 11:46AM   #5
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2 450 CFM carbs does not come close to equal q 750 single!Pontiac used a pair of 625s on there dual quad applications for a reason.They also made a change to a pair of 750s for a reason.If you are running 450s you wont come near the performance your looking for.Tom
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Old 05-10-17, 02:15PM   #6
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You may be right Tom, I just read that in the "back in the day" Holley carb book I still have .. a portion of the comparison curve on actual cfm comparing the 2 was less but not much less, and way more than youd think for a 450cfm rating. I was surprised by the fact Offy made kits for these carbs specifically, I have those new kits from them and the carbs, the kits slightly raising them ... and am a carb guy partial to Q-jets. I liked the idea of smaller secondaries q-jetalike Holley's because unbogging a q-jet for snap throttle performance with those huge secondaries was always a chore for me. Gratifying when you get it tho. Thinking for a street car the smaller secondaries would have a nice "feel" and be easier to unbog. The area * 2 of them I hadnt calculated yet but may be more than a single q-jet. I have an RPM manifold and a trusty 800 DP Im sure would be easier, but will try my hand first with the Offy setup. Getting them to flow identically and sync'd will be tricky.
Believe the shortblock will be strong enough to turbo and/or efi later. One reason I tried to beef it alittle. My goal was 10-20% more than the factory 390hp mark right now so I hope Gach's estimate is a little low for the first iteration. Im basically a rookie so he may be right on. Not sure why. Rookie logic doesnt always equate to HP most likely.
I wish I could measure the head flow of my 3 head set candidates in a stripped condition. I may try to with a timer, a water hose, a 5 gallon bucket and a digital scale once they are all the same cleanliness-wise. OK everybody stop laughing Will soak them each in an Evapo-rust tub, glass-bead them and try to cc them both port and and cc wise with my Isky kit first. Then choose one to try to get to 20% more speed and flow than stock 428 670's.
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Old 05-10-17, 03:49PM   #7
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With stock heads and good intake-carb and enough cam you can make right at 1-1 HP-CI.You would need about 230-236@50 and 600 min with a hyd roller cam.A little more duration with a solid roller and flat tappet cams.My 455 with stock 48s at 9.5 CR with that cam and a HSD intake and a 850 holley made 449.No headers or spacer.Long branch exhaust.And it was done at 5800.Tom
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Old 05-10-17, 08:31PM   #8
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a RA IV cam with 1.65s might get you there as far as the cam goes.Intake-carb package still would be a issue IMO.Tom
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Old 05-11-17, 01:02AM   #9
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Keith what exactly are you trying to accomplish?
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Old 05-11-17, 11:49AM   #10
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Lou,he has been looking for HP in all the wrong places.Tom
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Old 05-11-17, 11:54AM   #11
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Lou,he has been looking for HP in all the wrong places.Tom
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Old 05-11-17, 08:09PM   #12
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I know.
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Old 05-20-17, 04:26PM   #13
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Gach, trying for the same feel as the 69 GTO I drove in my younger days, supersized alittle. In my 71 Formula. In something I can take to track and not break easily, that can be improved on in the future. Nothing really specific. I will know it if I get there. The 068 cam is a Nunzi 2041 actually .. still has black coating on lobes. Info on it that I have found indicate it has adv duration of 068 .050 duration of 744 and lift nearing that of an 041 with wide LSA of 113 supposedly good for a wide power band. I have not found info on IVC event which I believe will be similar to factory 068 since adv duration is the same. Be nice to get better picture of DCR. Wondering what kind of CR it will tolerate .. counting on Calico ceramic topcoat to minimize piston heat differential both to ward off detonation and not wick heat energy. Cam ramps appear very fast and I think the Ti valves weight savings as well as the Rhoads lifter action will complement the cam especially if I use 1.65 rocker ratio. I think both 1.5 and 1.65 are "in the window" of good functionality with factory head ported or unported. 3.23,3.31 or 3.42 rear 3.55 too much for street driving. DQ setup may not be what I want but I'm curious, and will try my best to make the 2 4360's suffice and be pleasant to drive. Redoing my CR calculations -.020 deck height moving my pair of nice 80cc 11's into the possibility picture. Along with modified 670 or 62's.

Tom was the cam you made 449hp the nunzi 2041 or a roller with numbers you were talking about? Nunzi is 222I, 232E @.050 . Guess I am confused about how DQ setups in the early 60's were turning enough rpms to destroy cranks and rods .. I thought 7-8000 rpm and I cant get 6500 with one now. Maybe they were on lower cid 389's mostly tho Im sure they were bolted to 421's as well. Surely the taller DQ's as well. Maybe those who say they turned that rpm are full of it I know I remember many saying Poncho's are always throwing rods, my take from experience being they'll easily turn those rpms and they sound so sweet there ... I never broke one. Did have some Tangent speakers in the Marine corps with KEF woofers that sounded so crisp and clear cranked, them I did blow several sets
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Old 05-20-17, 04:39PM   #14
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I was racing in the 60s and did spin my 421s over 6200,little did we know back then that the dual plane intakes peaked at around 5800.I dyno a couple engine builds a year now and have learned we were over reving them.I found it out at Carlsbad when I short shifted and went quicker.All that fancy stuff your doing you would not vertically see on the duo.HP is in the heads-cam.Tom
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Old 05-20-17, 04:40PM   #15
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