The old 993s were about the best of the open chamber sbc heads. John Lingenfelter flow tested a bunch of production heads back in the 80s and came to that conclusion. He ported and milled them & used them on 383 builds. He was a pretty sharp dude. That was back before the hundreds of sbc head choices we have now.
@@lollipop84858 I'm saying the fuckin 993s were allegedly some of the best open chamber stock heads, but all I would use stock iron heads for would be a wheel chock, or a boat anchor.
The heads you are referring too are the 993 Hecho in Mexico heads that John was using NOT the 993 smog heads ! I have a set of 993 Hecho in Mexico heads on my bench being ported and actually from stock they have awesome features for a STOCK head !
There probably isn't 10 horsepower between all of this heads including the 882 that everyone says is junk. They all suck, but they all got the job done. I've rode in several cars with 882 turds that screamed.
The rotator was for unleaded fuel compatibility. I know because I read everything in those days. My first new car was a 1972 Chevy Nova, 350, 3 on the floor. $2850 out the door. It had those 882 heads, which I still have somewhere. They got replaced with a pair of 1970 400 heads which had the closed chamber, and a larger 1.6 exhaust valve to go with the 1.94 intakes. The 3863151 350hp 327 cam, $38 at my Chevy dealer, really woke that engine up.
I built a 350 for my Camaro back in 2020. I used 041 heads off of a 400 but they only had 1.50 exhaust valves. They were 71 castings I believe. An old machinist told me about the 70 heads with the 1.6 exhaust but I never have actually seen any. Cool to hear about an actual build with these heads! The engine in the Camaro ran great but honestly, in the current day and age, by the time I bought the heads, had new guides, seats, valves, ect. it would have been cheaper to get a new set of Vortec heads. But it was a cool old school build, probably something similar to what guys were doing back in the 70's and 80's to wake up their smog motors.
Thank you Erik for the efforts to compare these GM factory heads! It was very interesting comparison, esp the 487, 487x and the chinese aluminum ones! I've currently the 487s in my '71's sbc, most likely with stock factory cam. Would you recommend upgrading the rocker ratio to 1,6 or rather swapping the cam to bring the better out of the old sbc? I wonder could you ever possibly flow and review the GM's 113s (aluminum) as they are also recommended a basic upgrade on stock sbc? Thank you very much for today's video!
The "Cheater" screw in studs are (the ones we use) Pioneer RM-348, they don't have the hex, simply pull the pressed in studs, tap for 7/16-14, was a cinch on the SERDI, double nut and screw them in with a dab of LocTite.
Thanks, Eric. You saved me from wasting time on a planned head swap. I was just getting ready today to swap a pair of 487s to some Speedmaster/Pro Comps. The cam is only 480 lift. So, as you stated, there is no gain. Also, the engine the Speedmaster heads were on are now getting some Brodix T1 heads, thanks to your videos. Your videos are very helpful. Keep up the good work.
Thank you for your enlightening videos and spending your time to contribute to the community of those interested in learning about cylinder head improvement.
882 I'd rather start with the 1.84 do the 194 valve job myself, tulip should work Looks like biq quench pad so why characterize as open chamber I call them wedge heads pinned studs- those were the days, oil 441 I used the spiral grooved k lines and also to convert to 5/16 I Sunnen od hone the valves 487 best to mill that ex corrosion rather than Devcon X would be nice to see with good valve jobs EQ were great all their parts How about a video on chamber designs, an overlooked place for improvement I asked about the B1 when you said there was room for improvement ( or something like that) cheers
Back in the early 90's my first sbc build had cast iron #461 heads and they were factory 23° 2.02 int 1.6 exh and I had screw in studs done 665 int 675 exh and the 383 sbc they were on with a 175 shot was a fun little street deal back then when I first started. Then in 2000 I bought my first aluminum heads with 2.12 int 1.6 exh shaft rockers, port matched super Victor Jr. Intake had a 250 shot and then went to a blower. Man bring back memories. Great video
Those 487X heads were supposed to be good open chamber sbc heads. I had some 041X and 461X closed chamber heads back in the day, both had bigger runners than the versions without the X.
I've had alot of the old double humps both 202/160 and 194/150 . They always made the best power however in my later builds the 882 heads were my cheap go to heads. They got it done too. Thanks 4 the knowledge tho man. It was good info for sure.
I've had good results from porting 487's. They will port out to a Felpro 1205 and with bowl work, 2.02's and 1.60's with minor chamber smoothing, they make good street heads with 85 octane gas. 882's make good heads as well with limited porting but they are thinner and will crack if you run lean or overheat the engine.
Great information! It would be interesting to see what the 60 grit polish does for the stock heads. Any chance you might do a video on the 801, 416, and 601 castings?
Thank you for this, I'm getting ready to build an IMCA Sport mod, this is very informative. There is also a Dart head that's approved for IMCA Sport mod.
The myth of the 2.02/1.60 stock 882 heads is true. I had a pair that came off a 77 Corvette L-82, open chamber 882s with factory screw in studs & guide plates with 2.021.60 valves. They do exist, but ive only seen 2 pair in my 40yrs of messing with this shit.
Hey Eric, Tim here, i aint a sbc guy, but this vid, shows valid difrences, and i just thought this was a KILLER tech vid........TY sir for all ur time and effort.......PEACE to you sir!!!
Great video. Have you done a video on the 416 heads that so many folks say are junk boat anchors. And that if you put them on a 350 it will be lucky to turn up past 4500 rpms.
Great data on the OEM low compression heads. If you must run factory cast iron heads, the best are the Vortec heads, if rules allow. The number is 062, but don't throw a 906 head away, they are very similar.
Eric, I’m curious, what is your attitude toward doing work on truly awful heads? I’m not speaking about ones which others have ruined, but those that came bad from the factory and remain untouched, and where the rules pretty much only limit bore size.
Great video. Those 882s are almost in Camel Hump head territory (recalling your recent video on the 461 heads) Cant wait for the dyno competition between these heads
Thanks for the info on these heads been wondering how they flow for some time, your work is helpful for us low budget guys. Putting a 218 224 comp cam on 400 with 9.7 compression, trying for good torque. Thanks again
I helped a friend with a sprint car in the 1980's. At first he was using iron heads and the car ran HOT no matter what we did. When he put on the first set of Brodix aluminum heads the water temp issues went away forever. He never went back to iron heads again. Do you think in an average street strip application an aluminum head on average could run more spark advance and get more HP due to less hot spots in the combustion chamber ?? of course here we are discussing open chamber which typically means low compression.
I really enjoy your videos.. I own a shop and do a lot of engine work like porting.. my best friend owns a machine shop. I'm there every day playing with his machines ..lol What I'm saying is if your views would pay attention to your videos, they could learn a lot.. even I learned from your videos. Thank you, sir..
@@jasonnielsen2125 ok. The facts are there. Nobody drove street cars with 1700 hp on the streets. Parts weren't as easy and readily available. Everybody in town didn't have a CNC machine in the garage to make whatever they want. The old POS 406 that got hot and made 600hp just isn't as cool anymore. Legends, just like Abe Lincoln.
I like watching your videos and your knowledge my question is why don't you make DVDs and templates for someone who wants to learn how to do their own head porting like on the vortecs or the older double jumps or the best big block factory heads like the 781s or 049 you could also make money I'm sure their are alot of people that would buy them I know I would keep up the good work sir I love how you go into details on what to do or what not to do
The swirl port heads? I have seen numbers as low as 165/116. They are junk. The chamber is pretty good but other than that there is almost no legitimate use for them.
Brings back good memories, mostly, of building “purestock” engines:) 882’s we’re everywhere and as a kid I definitely got into grinding them with my Dremel and shopvac dust control in my parent’s basement. Stud pinning was the the pretty common affair with the occasional use of ‘cheater’ studs that threaded in but didn’t have a nut shoulder so you had to double nut them to tighten down. Sometimes I was lucky enough to work on “camel humps” for the Street stock guys! When I worked in the shop we used liners to bring back guides. The process had a bunch of steps but went really quick with the right tools. Something like: bore guide, press in liner, cut length, broach and finally ream to size. Then put the pilot in and grind the seats. Grind and Reface valves on the Sioux City. Probably about 30mins a head then off to the Jetspray washer before spring height check/shim and assembly.
Id like to see some flow tests on the 991, 185 heads with 1.720 intake valves and the 416 305 heads with 1.840 intake valves. High flow numbers arnt always better as the small valve heads have smaller flow numbers but increased velocity at low rpms for smaller cube engines is why they used them on 283s, 307s, 327s and some 350s for towing.
487X are commonly foundon 71 and 72 LT-1 Corvettes and Z28 Camaros, they will have guide plates and screw in studs with 2.02/1.60 valves and the combustion chamber relief cut for the 2.02. The 996 heads could be found on the 73 and later L-82 High Performance motors with the same valves and screw in studs/guide plates.
Ive seen 882 or 441 heads with 1.72" intake valves for box trucks. The 1.50" exhaust valves usually have 3/8" stems. I don't remember any chevy heads having 1.86" intake valves. 305s have 1.84" valves but they need very small combustion chambers or they wont have compression so you wont find these big chamber heads on a 305. Perhaps since its in the factory parts bins, there may have been low power engines with 1.84" valves but i never encountered it. Perhaps machine shops would put 1.84" valves in place of the 1.72" without doing too much hogging to make them fit. Anyhow chevy had a weird habit of using certain castings in different applications and theyd have entirely different hardware depending on the application. But theyd still have 3 different castings with more or less the same dimensions. And theyd have different casings with the same casting symbol. There were numerous "double hump" heads. And there was more than one hump shape and most had no bolt holes but a couple did and the ones drilled for accessories were clearly cast differently to accommodate the brackets.
My 993s have had bowls done by indy and i worked the pockets and bronze guide bosses the runners have been rasiused and smoothed on both int & ex. Assuming all done correctly Does that increase the flow much on a 993? They also have 2.02/1.60 valves but I hear the 2.02 gets shrouded and actually hurts the intake flow. Im thinking of having them cut some but not much to avoid intake fitment issues. No there not for racing just a hot rod cruiser obs pickup and the 350 with the those heads runs nice n strong with a typical 230° .480" cam. Good enough to pull on a turbo subaru impreza and roast 295s without using the brakes.
I’ve had every one of those heads in the video. The 441s were on a 350 in a 1970 C10. That was one of the strongest pulling stock small blocks I’ve ever had. The 487xs are a good head, I sold those to a IMCA guy. The 882s I sold for scrap.
the procomp head struggles below .300 lift BUT we make better valve cuts to achieve better low lift numbers on these heads! on both the seat and back cut on valve. Besides, this is 2024 and no one runs .400 lift cam! not a single customer has ever requested such a low lift cam, other than old magazine builders that don't know any different or some budget roundy round class racer. Most every cam and head combo i do for customers starts off with .400 lobe, HYD roller. Bang for the buck you cant beat the ChInEeS hEaDs. Yeah they need some attention to be better, guids & valve job but what head doesn't?? (dont say dart, brodix, RHS that cost 2x the price)
Great vid Eric. I was looking for flow specs for the 487 heads on my 71 vette. As for the casting symbols, I'm not sure if the 487 symbol is different from the 487X. On my heads, one end of each looks like the basic 487 symbol you showed while the other end of each one looks like the 487x symbol raised on a box. Next time I have the valve covers off I'll have to see the internal number to confirm if I have the basic 487 or the 487X.
I believe the four hundreds from the factory with a 993 casting number only. Have had bunches of stock 400 and have always had those weird markers on front
I have 993 heads they say there like 441 but flow alittle better. I ported them a few years ago before I found your channel. I was on subs aand fish so I used water flow knowledge to port them. some day I would like to send them to you and check them out.
The as cast differences react better to cam upgrades, by a small amount. But if that's what you have to run, a small improvement is a good improvement, lol. Most tracks that mandate these type heads won't allow any porting or gasket matching, the most you can do is to machine cut them with the bowl hogs.
Makes me miss my 400 I built 8 years ago, stock 2 bolt 400 out of the local pick and pull a comp tow cam z28 valve springs and 882 heads slightly ported with 1.62/2.02 valves 1.6 rockers, flat top pistons, aluminum Camaro intake manifold with a q-jet through stock manifolds it passed ca smog in a 78 c10 350, it was definitely chocked up past 5500rpm but made tons of torque with a 2500 stall 4.56 gears and 31in tires, it would burn the tires until you let off
Interesting stuff,how does stock Chevy heads flow compared to other car makers stock heads? What does Ford & Mopar got to beat the Chevy guys? That would be quite interesting to see also,and IF You would do that throw in a AMC stock head also,I've heard the AMC ****502-* heads from 1974 should be a pretty good flowing head "for what it is..."
I think the people that say they are not open chamber should think of these heads as large chamber. They are probably 76cc chambers where the small chamber sbc heads of the 60's and early 70's would have been 64 cc. Those small chamber 64cc heads will give astronomical compression and they show up in the high horsepower factory small blocks that required high octane fuel.
That X head was probably from a Corvette. They had X blocks too. Also the LS has identification bumps along the valve cover perimeter on exhaust side. 243 has different bumps from 317 and on .
Have you ever done Canfield 220 65 cc chamber heads? I have them on my 406 sbc I think they work great but I’ve had them a long time Your thoughts?? Should I upgrade to new heads I bracket race
Having had a little to do with these gunkers, and Chev heads in general the cut below the intake is factory. AFAIK all at least earlier GM heads had a similar cut. Depending on the casting depends how much. I can remember scrapping these heads as they had no value. These days however they do,, more so with part number junkies on restored cars Fuellies too were done like that. Factory retainers and collets IF in good order will be ok on a Fuellie with low 500 lift. Oil shields fall off on std engines, that I have seen on Chevs and Holden 6 and V8. Any more lift go good aftermarket. Not ProComp,, I saw one of those retainers broken as the collets tried to pull through. Rotators on any remotely performance engine wil fail and cause dropped valves. Not just GM used them on smog engines, a patch to try and make the engines live to outside warranty. Use 5000rpm regularly and they will cause an issue. Those D shape chambers are useless, and they get detonation on standard engines.
When looking at a small or big chevy heads, it looks like the "closed chamber" heads have a quench pad on both sides of the chamber and "open chamber" heads do not have quench pads on the spark plug side. We used to refer to Pontiac heads as either "Large" or "Small" chambers and we have a 1974 SHP Z28 350 that has 882 heads with screw in studs, guide plates and 2.02/1.6 valves. Keep rolling......
@@chrishensley6745 screw in studs and guide plates. We would put it all in double hump castings and change the cam and intake and those engines would run pretty good.
I just got some amazon sbc heads and after watching your videos im questioning if theyre worth it. The bowl arond the seat is bigger than the seat and the bowl cut just scratches the casting slag. So i dont think they will flow good even if i cleaned them up. Also they are afr copys so the guides seem thin since they are bored to 11/32. I dont know if thats good or not.
@@billcat1840 and cleaning it up with a sanding roll would only make it bigger. How would you make it smaller? Im probably just gunna send them back. The combustion chamber is actually nice. No lips or shrouding at all and smooth casting. The runners look like doo doo though.
@@____MC____ think I would send them back too. Too much work to make them flow right. Sounds like an amateur selling ported heads...just hogging them out is a beginner mistake...I made this mistake myself years ago and had a turd of an engine
Need a Biiiiiiiiiiiig cam and cubes to get those bad boys flowing, had a 500 thou and 109 cam in a 355 and it was a shot pig……. Put a set of fuellies on it and the thing would turn tyres alllllllllllllllll day. 👍👌
Ok, forgive my ignorance. I've had this discussion about ford heads before & it's was confusing to me that their was confusion about ,to me, what was obvious! And I see the same here, in the chevy circle. What is your definition of a "open chamber" head? Becouse I see the title, "open chamber" tests!!! And yet I see a thumbnail of a pic of 4 closed chamber heads? Why? How? What is your definition? Ford heads we say open if it's "open"!! No quench pad or a quench pad not on a level with the deck!
The closed chamber heads on a sbc are around 64cc or so, all 4 of the heads in this video were open chamber, 76cc. Notice the spark plug bung in these heads, how it protrudes into the chamber, the closed chambr heads will have a recessed bung for the spark plug.
@@jesseduke694 The reason the differences in the spark plug bungs are that the chambers are smaller, hence 64cc volume, vs 76cc volume. The way GM made the quench area for their closed chamber heads, made the spark plug bungs appear either exposed completely, or it appeared to in a recess in the chamber. That's why I suggested you LOOK at the chambers. You can mill any head, but the more you mill it the more it affects other component fitment, and clearances. You run into valve to piston clearances, rocker arm and pushrod geometry and length differences, intake mounting differences, and so on. By the time you do all that, you can have a set of good closed chamber heads for it cheaper and have better performance. take a stab at googling the questions you're asking here, there is a lot out there about this.
The small valve 882 heads had 1.5 exhaust and a 1.72 intake. The 1.84 intake valve was a 305 thing. The early 305 used the 1.72. The later 305 heads had 58 cc chambers and with .480 lift cam would really wake up a dish piston 350 for not much money. A flat top piston 350 would break the ring lands out of the pistons in short order with the 305 head.
