Final Episode of my 406 SBC Chevy Build We return to Watter’s dyno and make several pulls and changes to maximize horsepower and torque. This engine is available for sale, and can be yours.
Thanks you for your comment David. It is an honor to have you comment on my channel. I have read your books and watched your video's, and learned a lot from you. AG
Im peggys husband, on my 400 sbc dyno run with an air gap i used a 2 inch 4 hole spacer, modified by cutting the bridge out between the 2 holes on the passenger side so that it was an oval shape. What it did, was equalize the plenums, because pass. Side is shallow, but drive. Side is deep. Engine sounded different and with jet change 20 hp. More !!
you take a 4 hole spacer , cut the 2 holes on the passenger side so they look like an oval it allows more cross atomization which the passenger side of a dual plane needs because it lacks volumetric efficiency due to it being shallow driver side is deeper allowing driver side to move more air and fuel
@@goldsgarage8236 I was most impressed with the torque at 2000 rpm and the swap to a 650 carb. I have a friend with a sweet, pristine 70 1/2 Z-28. I think the factory Holley was only on this year Camaro. I think 780cfm. More than enough for 350. Nice bragging rights, but it too would be better with the 650. His car is probably cleaner, even on the underside than when it was new.
Thanks Randy. The 67-69 Z28's came with an 800CFM carb, they used the same carb as on the L88427. Not sure about the 1970Z's. Remember GM built these cars for Trans AM road racing and they were spun to 8000RPM. The smaller carb will give better throttle response on the street. AG
@@goldsgarage8236 The 1970, or more commonly know 1970 1/2 Z-28 with a 350 came with a 780 Holley. I think it was special for this year only, I could be wrong. This was the last year of high compression. The Z-28 option had 11:1 compression. I'm only familiar with some specs on this particular year because a friend has one. The car was in Chevy High Performance magazine many years ago. It stays parked in a garage and covered. I think a lot of manufacturers in that era played with guys brains by having those big carbs. That said, big is always good for bragging rights. 😁
Please give Gold's Garage a "LIKE" if you have any appreciation for what he does! And thank you Allan Gold for the 2 video's this week, and all you do!!
It's an issue few would ever face, but I managed to take out an electric water pump by neglecting to remove the ratchet after lashing the valves. (once) Now I remove the ratchet after each turning of the crank.
The 1.6 rockers helped by getting the intake valve off the seat faster making it seem like it had a larger intake valve. Helping scavenging would have like to see if 1.6 on the exhaust would help too. With the larger ratio rockers improving power leads me to beleive the lsa of the cam is to wide for max power. But it will be easier to tune and drive on the street.
Surprisingly in many builds leaving lower ratio rockers on the exhaust delivers more torque which is what power is based on. For a street engine low RPM torque and a flat torque curve is the bees knees. For speed trials like Bonneville Salt Flats, HP at high RPM rules. The only way to know on any build if increased rocker ratio will be an aid is to test on a dyno.
@@____MC____ seems most times engines are either over valved on exhaust, over duration or both as cams usually designed to work with stock or near stock poor flowing exhaust systems, when open exhausts or better exhaust systems are in place then more inlet valve velocity has a positive impact on performance without any changes to exhaust side, just my general experience, I heard Darin Morgan say similar comments on exhaust valves in performance heads too
With an estimated 460 lb ft at 2,000 rpm, it sounds like it would work well in a 1/2 ton hauler with up to 12,000lb GVW. Even in the up to 9% grades we have here in BC!(Which I usually climb the big hills at 2,500 with a 350)😉
Cannot imagine why you didnt start with a 750 cfm carb ? David Vizard would tell you that camshaft is way off of what is needed. Should have a 105 LSA would make more power thru out the RPM range Probably another 30+ HP
AFR heads and most modern heads have efficient combustion chambers and dont need that much timing advance. They are not like old sqaure chambers. 28 to 32 is all you need. 1.6 rockers work well on stock or near stock cam. They're a crutch to make a small cam act a bit larger but the law of diminishing retunrs sets in hard with cams in the above 220's. Then you also start the risk of vavle float.
That isn’t true. The combustion chambers are pretty much the same shape and sizes since the 60s what’s become more efficient is the increases runner sizes and ability to flow more air making them more efficient. Most of the new heads still running same 2.02 1.6 valves they ran 50+ years ago. Yes you can use 1.6 rockers to help with a smaller cam but they’re not a crutch they’re an option that can be beneficial or not depending on many factors but they are not causing valve float. You can float valves with 1.5 just the same when you get rpm’s up to high. It all depends on the valve springs. But in reality the only thing causing valve float is the operator.
That is fake news. But dont take my word for it. Call AFR and discuss it with them. They did the research and design and they will tell you the same thing. I know because I have done the same engine with the same heads and called them to ask. Look up and research heart shaped combustion chamber and all the related properties and benefits that design. The LS chamber was adapted and reverse engineered in this regard. @@Thumper68
@@icsamerica the chamber has always been heart shaped it’s just been improved over time and with better building technology but it’s nothing new. And I don’t need to call AFR my old man’s a master machinist and mechanic for 50 years and been building 700 hp sbc minimum 35+ years being some of my first memories.
@Thumper68 100% wrong. Go look at the chamber of a set of fabled camel humps or just about any other SBC heads before the Vortec design. Hint... it's not heart shaped like every modern high performance SBC / LS is head now.
Awesome video! I built a almost identical 406 last winter but used the project x promaxx 200cc heads and very close cam to yours with the 1.6 rockers. Mine also was 11:1 compression and it is a blast to drive out on the street in a 1972 c10. I didn’t dyno mine so it’s nice to see what kind of numbers it made. Keep up the great videos and you have lots of good information in them.
@@goldsgarage8236 Mr. Gold What is the 🤔 price of just the parts? No machine work or assembly, just parts??? I am thinking 🤔 about buying the engine.
Those AFR Enforcer heads are the real deal. I figured that they would end up being just another mediocre cylinder head like all of the other ones but these perform like the more expensive ones do.
They are nothing special. Most the knockoff castings, nkb etc might see 250/180ish Like a ported set of camel humps Nowhere near the quality of head as thier eliminators hence "cheap" I know, I got 2 pairs, stock and ported/flowed. Huuuge difference.
How much are you asking for the motor? I love the fact you tested the 650 carb on that motor, it actually proved something I had been debating. So often car guys run too large carb, A 650 will support 500hp.
@@goldsgarage8236 That is a fair price for a proven piece tested ready to go Spent 18k on a 383...coulda done it for less but I skipped no step and love shiny stuff.
Thanks for the comment. Sorry about that. By the time we installed the 650 we already had enough videos of the pulls. Guess we could have added one more. AG
Take the 1.6 off the intake. Put the 1.5 back on the intake. Put the 1.6 on the exayst and run it. Then put 1.6 on all of them. Run it and show us the dybo on all three runs. Graphs preffered
Really good video I have been wondering if the rocker ratio change would be beneficial or not so I'm glad to see you did this test and had a gain in power. Thanks for the videos keep it between the ditches
You could try an edelbrock VRS 850, or maybe on that boat engine seems like they make tuning really well and driving easy with more leeway. Cool Vizard video also.
I have seen a number of dyno tests that indicate best results with higher ratio rockers on the intake. The intake on a NA engine operate with at best atmospheric pressure in the port, while the exhaust has about 100PSI in the cylinder at EVO which allows the exhaust to function well with smaller valves and lower lift. Depends on the specifics of the ports and the rest of the engine.
Nope! Atmospheric pressure at the intake port?? Yes! When the engine is turned off! But When its running the piston travels down creating a vacuum and sucking air in... same.piston speed as when exhaust is pushed out just the other direction
@@1DEADBEEF1Reread my post. When the EVO's there is still in the neighborhood of 100PSI in the cylinder that initiates blowdown and the pressure wave in the exhaust.
I believe physics say you can push air but you cant pull it. Imo the intake charge is not sucked into the cylinder, atmospheric pressure fills the void/absence of pressure created from the action of the piston decending. Atmosphere can fill a vacuum/absence of pressure very fast near the speed of sound.
@@stevenbelue5496This is true. A "magic" number for head porters is 300 feet/second in the intake port with 28 inches of water depression. Now in a running engine just as the intake valve opens, the pull of the exhaust pulse during overlap, can create over 100" depression across the barely open intake valve. As the valve opens more air passes causing the depression to drop even as the piston velocity increases. Maximum piston velocity occurs at approximately 70° ATDC and BTDC. Exhaust velocity is highest at EVO due to the residual cylinder pressure, which is approximately 100PSI. This creates a high pressure supersonic pulse out the exhaust which is higher pressure and velocity than what the piston creates as it rises on the exhaust stroke. The intake is restricted and cteates pressure drops to the atmospheric pressure from the air filter construction, throttle position and friction with the port walls. The closest to atmospheric at the port side of the intake valve would be low RPM and high load, wide open throttle.
Thanks for your comment and detailed information Dale. Sounds like you have a deep understanding about what is going on in the engine and have started some good discussion. AG
I wish you would have still put the 1/6 on the exhaust to prove your theory I believe it still would have helped and I know from experience guessing is never the best option when you have a chance to test
I have watched some of your videos and will watch more when I need to turn a crankshaft I use a adjustable wrench it doesn't mark the crank it grips the woodriff key
VE went up with the 650 ? why, coz it flowed less air ? Also if we're so afraid of over scavenging even with the little cam, why not fit a single pattern cam, it'll make less power but you won't be worried about "over scavenging" is that a fuel economy thing ?
Aluminum heads may be different, but with stock heads, we found an improvement with 1.5 on the intake and 1.6 on the exhaust over 1.6 on both. I am assuming it helps with the limited exhaust flow of the unported cast head.
Thanks Leland. The 1.6 should help in a car with a restrictive exhaust. I think that is why cam companies make dual pattern cams with more lift and duration on the exhaust. AG
Very good question Robert. Camshaft lift is limited by duration because there are limitations on how fast the cam can lift the valve. More duration may not be desirable because it can cause loss of low end torque, idle quality and overall Streetability. Lift helps everywhere with none of the negative effects. Using 1.6 rockers allow more lift without increasing duration. Hope this helps. AG
Thanks. I enjoy your channel. You have a good combination there. That’s going to be a great street engine for someone. I have those same heads on a 350 in my S10. Been running them almost a year now. I never leak down tested them though. They seem to be doing good so far. I was thinking about doing a 400 short block so naturally your build caught my interest. You gave me a good idea of what to expect. Those are good hp and torque numbers.
Thanks Big. Darrell's dyno measures air flow through the hat and then fuel flow to front and back barrels, then does the math to get air fuel ratio separately. AG
not necessarily you watch to much Eric it only out performed the newer Victor JR by 25 HP the old Victor JR was the best by 6 HP over all out of the rest of the manifolds tested, watch again.
@@fredlogan3849 PROVE IT.WHY HAVE ALL THE STOCK CAR LOCAL SPPEDWAYS RUN VICTOR JR FOR ALMOST 50 YEARS. IT WORK. IDONT KNOW ERIC YOU ARE TALKING ABOUT. I BEEN AROUND 50 YEARS DOING THIS. WHAT ARE YOU REFERENCE I SHOULD WATCH ??
Leaner will almost always make more power.. richening the mixture makes it safer but will decrease power.. unless it’s so lean that it’s not running well
Good question Steven. Yes, I would suggest checking it. Minimum clearance occurs on the overlap cycle when the exhaust valve is closing and the intake is opening. You can check it without disassembling the engine by using a dial indicator and light checking springs. AG
Thanks Josh. Ballpark estimate, with all new parts, Dart block, forged rotating assembly, roller cam and stud girdle, balanced, dyno, etc. $12-14K USD. AG
This may be a dumb question, but when you're selecting valve springs to handle a certain lift, what rpm is that lift rated for? I was just watching an old vizard video and was saying that you dont need more than x-amount of spring pressure on a small block which happen to be lower than the springs i ended up getting wich had a rating close to the lift im running. It would make sense to that he may be right and the springs i chose may be good well past the operating rpm range of my 383. Im i on to something with that? He said 330 to 360lbs My springs are rated to 438lbs it also says its 412lbs @1.170" and my lift will bring it to 1.220". Also 136 lbs seat pressure.
Thanks for the question @___MC. We need to know more about your cam but your springs are big for a street engine. Looks like your cam is a roller, if so i would agree with DV.
@goldsgarage8236 i was under the impression that tapered springs do the same job with less open pressure and a progressive rate, so i figured i might be on the low side untill i saw that video. I dont have a spring checker, so i have no idea what pressure is a 1.220".
@goldsgarage8236 in vizards spring rate graph, the tappered springs have a pretty linear rate, so i graphed it out and got about 390lbs at 1.220 compression.
We put modern Comp Beehive springs & retainers on my World heads when we freshened up my 409 small block. Seat pressure is 105lbs & around 305lbs open running a .550" lift hyd roller cam with 1.6 Comp rockers on both sides. Beehives are more stable & a bit lighter so they control the valve train with less pressure. I've switched from 1.5 to 1.6 rockers on motors with short duration cams & have seen a noticeable increase in power, which goes along with GMs LS motor components, 200cc intake ports & cams with around 200* duration & high lift with higher ratio rockers. Best of all worlds, driveability, mpg, good power & lower emissions.
Can I ask you what exactly has DV ever done in racing? At least your friend has a raced a NHRA class car, please stop mentioning DV in the same sentence as your buddy.
I’ve been reading spark plugs my entire life. You can spot check them like your doin. But you can absolutely not actually see what you need to unless you cut the spark plug. Do it right or pay the price. CUT THE PLUGS.
We were having some issues with interference when the Mic’s were too close together, so we tried using just one in the dyno cell. We put one on him at the end of the video.
This was a roller cam engine so break in is not an issue. For all flat tappet cam engines i break them in on my test stand in my shop before we go to the dyno. AG
Thanks for the question Ssjay. It is going into a 4 speed car but depending on the weight of the car I would suggest 2400 Stall and at least 3.55 gears. AG
Thanks for the comment Richie. Yes, we should have tried 1.6 on the exhaust. We were concerned with over scavenging. 1.6 rockers will help your stock heads for sure. AG
Thanks for the question Daniel. No we did not flow these heads and did not do any porting at all. Skip White publishes the flow numbers if you are interested. AG
You are correct Thomas. There might have been a few more HP there. We felt that we had achieved our target and we wanted to get Will on the road, he had a long drive. AG
Where’s all the data??? Where the 1.6 exhaust rockers??? What’s the point in doin actual tests if I’m the end your just going to make assumptions??? Anyone can make assumptions aka talk shxt. Makes no sense that your armed with the equipment to fulfill real tests and just settled with assuming. Come on guys step it up. This was a wasted video. Zero data sheets at the end. Didn’t show comparisons of one set up to another. Where’s the DATA? Where’s the 1.6 on intake and exhaust??? Side by side dyno charts showing the difference in torq and hp at wat rpms from one setup to another setup??????
Nice engine, i could bring the power to 550hp 540 torque by a cam swap. If the cam was something like 241 244 590 590 lift on a 107 lobe this engine would make 550 hp and close to that in torque.
Thanks for the comment. You are correct. I am pretty conservative on cam selection. Drivability, throttle response, low end torque are priorities in a street car. AG
Il@goldsgarage8236 I do agree, however I'm always surprised how well these 406 motors suck up a big cam. I have a 406 in my 63 biscayne with a 247 253 560 540 on a 106 and the holley fuel injection works perfect even with only 9.5 vac. Flat tappet solid old school budget build.
My guess that there is 520 hp in that engine if you would balance the A and B of the carb. What you needed to do was lean out the A side and richen up the B side until both sides of the carb is flowing the same amount of fuel. Looking at the dyno sheet you have over 20lbs of fuel difference. They need to match.
Thanks for your comments Racer. I agree there is more in the engine. Darrell did do some jet changes to balance the flow but by the time I changed rockers and I got my 500HP target we were running out of dyno time. Your comments make good sense and next time I will focus more on that from the start. Thanks for your input again. AG
@@randywl8925No, high side and low side. Dual plane manifolds split a V8 in half left to right. 180° pulse versus 90° with a single plane. Basically fuel distribution related.
