i know the chamber design is different. i have a set of 59 fuelie heads that have an open chamber when compared to my power pack heads. hope that was the question.
Fuelie heads means it originally came with fuel injection, so they are rare. Hump heads have been called Fuelie heads, but it is a common mistake.
To much misinformation !! Chevy never made a Fuelie head or a Fuelie motor either. Chevy did install fuel injection on the hi HP motors that were available, however the option was rarely ordered as it had a reputation as troublesome. The Hi Performance heads seen on Fuelie equipped motors were not ever made only for that option. The early HP head never had a big chamber, it closely resembled the early 289 Ford chamber with a chamber pocket around the spark plug area.
All Chevy heads made after 1987 were made for fuel injection. I had to add that. Before that = No Fuel injection heads were ever made. Most Chevy owners have not made big attempts to stay in touch with reality.
Here's the 'list' right out of NHRA tech inspection data for '57 Chevrolet: You'll notice that ALL V-8 heads are the SAME, be it 265 2bbl or 283 FI Head H.P. Disp. Gasket Cast 140 235 162 265 .018 3703523,3767460,3795896,3884520 185 283 .018 3703523,3767460,3795896,3884520 220 283 .018 3703523,3767460,3795896,3884520 245 283 .018 3703523,3767460,3795896,3884520 250 283 .018 3703523,3767460,3795896,3884520 270 283 .018 3703523,3767460,3795896,3884520 283 283 .018 3703523,3767460,3795896,3884520
so why was i just able to find eight different casting numbers that apply to 1957? with one casting number, 3731539, specific to 1957 283 HP FI 283 CID?
Power Pack were the good heads until the double humps came out. Power Packs had 1.72 intakes and then the camel hump went to 1.94. in 1962.
I've seen that listing, and it has fucked up a lot of people. The real deal is------both the '57 220 hp 4 bbl engines and the 283 hp fuelie engines used the same head, the "539" casting. The 270 hp dual quad solid lifter engines used a different head casting (ending in "997", I think). All of the '57 heads had 1.72/1.50 valves, although the hipo engine valves were swirl polished.
Yes,but the 3795896 head first appeared around 1962 on the 283 and 250 hp 327???.Otherwords it's a replacement head for the early head??
That's the list of head castings that NHRA ALLOWS to be used on those engines. Those are not the head castings that originally came on those engines. I've got a set of '57 heads with the "fuelie" casting number... it's a different number than the other heads (2x4, Power Pack, etc.). I have not had a set of Power Pack heads to compare them to, but they ARE specific to FI engines. -Brad
Is the "listing" you are referring to Car & Parts Catalog of Chevy V-8 Engine Casting Numbers 1955-93? If so I have that and am looking at it and it says the 3740997 head was used on Passenger 2x4 bc & 250hp F.I., 220, 245, 250, 270 hp Corvette, and Truck 4 bc 283's in '57. The 3731539 head was used on all 283's including Passenger 4bc and F.I., Corvette 283hp/283, and Truck. I'd like to know what differences there are in these two heads.
Yeah, all I can say is.....more misinformation. It can be difficult to know what to believe when looking at charts like that; you never know who put them together. I don't have a pair of 997s to look at, but I THINK (not guarantee) that they had an ultrasmall combustion chamber, similar to the '56 306 castings. Anyone that wants to argue about it without offering any proof, feel free---the older I get, the less I give a shit about such things.
So , kidagain , I guess this helps you out? , got it all strait now? crystal clear now?.... or are you like me and more confused than ever now? , I thought I knew a little about casting numbers ....never underestimate the power of the H.A.M.B.
Here's the deal with any type of a list produced or book written about what used to be. Most if not all are flawed in one aspect or another. I don't have acess to one but someone must still have one and that would be the original list from 1957. That is the only way that you are going to find out for sure what it is that you want to know about what was offered on what combination was available. I do recall that there was a different head that were generally refered to as a fuelie head back then. Of course I wouldn't have been privey to the information until the mid to later '60s myself. The Ol' Man wasn't a chebby man and I recall him refusing to even tune one if he didn't know you real well. Anyway by the time I started fooling around with Chebbies what was called a Fuelie Head had ports that you could measure a difference from the power pac and thde combustion chamber was a little larger supposedly to unshroud the intake valve. I have no idea what the casting number is an older friend of mine had '57 Vette topend and showed me the difference. Now this is probably also flawed because I would have been about 15 at the time and that was a very long time ago.
LOL hesterically! I'm not sure which end of the distributor goes where now So will some really old dude (I'm pretty damn old myself, just don't know a damn thing) comment: Would it be better to use 57 fuelie heads on my 265 or the 57 power pack ones? Some casting charts show different numbers for them. According to http://www.jimsperformance.com/headchart.html the 283hp 283 heads (no reference to FI) was 3731539 and there were quite a number of castings listed as "1x4,2x4, FI Corvette". Maybe his list has some flaws? So can anyone tell me if there was something physically special about the 283hp heads or where they just the ones the put on the 283hp motor? That would seem dumb but doesn't mean at ain't the truth. PS I'd be happy to learn from a really "young" dude too.
To answer the original question; ..... it depends. Here's a page out of the Master Parts Book. http://chevy.oldcarmanualproject.com/1929_57chevyparts/57cmpc0136.htm The "539" head was used in pass. cars with 4BC, and pass./Corv. w/F.I. AND the H.L. cam. (I'm assuming that's the Duntov solid lifter cam) The "997" head was used on dual 4BC cars without the H.L. cam and Corv. without F.I. and H.L. cam. Clear as mud now???
All I can add is that the 997 heads that went on the 57 passenger cars with 283 and 2x4 carb set up are rare and expensive, I passed up a matched set priced at 3k, I am not there yet with having to have them because of the marking (one small tower) and a 997 number. The 1539's are plentiful and less expensive. Not much difference in performance as you would be even better stepping up to a 327 head. For use on the 265 check on here.There are some good threads on build ups of the 265. It will be worth doing some homework as the 265's had their own specific problems with oiling I believe.
Old Dude here.The 539 heads were used on both the 4bbl and the FI engines. The FI engines got pop up pistons. The 539 heads had a larger combustion chamber than the 997 heads so that worked with the pop ups in the FI engines. The 270 HP dual 4 engines used flat top pistons and got their compression from the small chamber heads. The 539 heads have the single triangle on top of the large rectangle. The 2x4 heads had two towers on top of the rectangle. I would run a 57 head over a 55-56 head as the ports are noticably bigger. I would prefer to run a 59 head as they have the cooling around the plugs.
ok, this thread is borderline insane. Back in the day, the so called fuelie heads had 2.02" diameter intake valves, whereas the powerpak had 1.94" valves, and the 2bbl heads had 1.72" valves. This is what I recall from the early years. Casting numbers are just numbers to me, show me the valve size!
Kid again, So now we have lots of information and and his daughter mis-information for you to muddle through. On a small displacement engine my personal favorite was just a set of power pack heads. I have a '62 Corvette (in theory) 283 that I'm eventually going to build. I don't know if the heads are "fuelie heads" or not. They are what we always called power pac heads when I was a kid. My intention is to keep the displacment 292 or smaller. If I open it up and don't believe it will breath good enough for me I own a dremel tool. You are going to find that unless you just get a set of heads that don't breath at all you won't find any power that you can feel by the seat of your pants by choosing a specific casting number. All the casting numbers in the world are just no match for a man with a dremel and the will to use it.
Okay, this is the last post I'll make on this subject. ALL "powerpack" heads (named for the '56 265 and '57 283 powerpack engines they both first appeared on ) had 1.72 inch intake valves and 1.50 inch exhaust valves. "Fuelie" heads (named because they first showed up on the '61 315hp 283 'vette engine) started out with 1.94 inch intake valves and 1.50 inch exhaust valves. In (I think) 1964, the same castings were opened up to use 2.02 inch intake valves and 1.60 inch exhaust valves on the 365hp and 375hp 327s, and were also used in this form on the '65-'67 350hp 327s. The 275hp and 300hp 327s still used the 1.94/1.50 version of the same casting.
You can drive yourself crazy looking for the right casting numbers and spending lots of money to get them restored but unless your goal is a perfect numbers matching restoration, forget it and buy a new set of Aluminum big valve heads from Edelbrock or others and be done with it. As far as a 265 goes you can flow more air through almost any 350 stock head than it can use. Even at 7000RPM you can't flow better than a Vortec head. And yes, I'm an old guy....