Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

17059216 new issues vs old issues

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73ss:
I've got a set of those 882's. They were removed from a 74 Z-28. They have 2.02 valves and screw in studs & guide plates. To the best of my knowledge this was the last year for 2.02's & the screw in studs.

I've had them for years and figure someone who is doing the "numbers matching" thing might want them for a '74 Z-28 or L-82 vette resto. I'll never use them. Someday I'll put them on flea-bay and see what happens.

Frank400:
Hey Olnick,

  the 041 heads DO have holes at the end.  They are 69 heads with 64cc.  I know as I have a set.

   Frank.

Cliff Ruggles:
041 heads were used in 1969 and 1970 on the 300hp 350cid engines.  They are very similar to the 186 castings used in the same time period.  All of those castings will have machined ends and accessory bolt holes.

The 041's are "sleeper" heads and most have slightly larger combustion chambers even though they are advertised at 64cc.  I've built a good many SBC's with them and the vast majority of the 041's we've used were closer to 66-68cc.

The earlier big valve/big port "double hump" heads will not have accessory bot holes.

Some time in the 1970 model year run they revised the 041 heads and opened up the chambers, these will be the 441 castings.  They still retained the larger spark plugs that require a gasket and big intake/exhaust ports.  336 castings started showing up and are pretty much identical to the 441's.

The 487's were next and ran thru 1972 and very late versions will have factory hardened exhaust seats.   In 1973 all of those heads were hardened seat and they changed the numbers to 993.  The 993's had every so slightly smaller intake ports as well.

The 882's came in 1974, and are the worst heads ever to sit on a 350 engine.  Power and efficiency went into the toilette and fuel economy on those engines was HORRIBLE.  I think the factory was really trying to please the EPA at that point and those engines showed up with TONS of vacuum hoses and devices to clean up the exhaust emissions, with no attempt to make those engines efficient in terms of power production/fuel economy.

For quite a few years crappy heads continued to show up on SBC engines until they finally figured out that by increasing the compression ratios and going back to more efficient combustion chambers that these engines could make the grade in all areas.

There were still a few "turds" produced for castings well into the late 1980's early 1990's, among them are the "swirl" intake ports (early Vortec designs).  Those heads are FANTASTIC for a truck engine build with all it's emphasis on low end power, but no so great for anything else.

Kind of interesting is that the later "Vortec" and other similar designs for the LT engines are EXCELLENT heads in every respect when it comes to compression, port flow and combustion efficiency. 

The big problem I have with factory heads is that all of the "early" heads prior to the 993's that have good ports are soft seats, and most are pressed in studs.  The 993's are hardened seat, but often cracked as the factory induction hardening process leaves them a bit too brittle in that area.

The later Vortec heads, although dirt cheap and readily available have MAJOR shortcomings including a "goofy" intake bolt pattern (requires purchasing an aftermarket intake for older engine builds), they are "paper" thin and crack easily, and pressed in stud w/o guide plates.

"continued"

Cliff Ruggles:
So what is one to do when building one of these engines and in need of better heads.  I use and recommend upper the bar and buying World Products SR, Sportsman, Dart Iron Eagle, Trick Flow, or other similiar aftermarket heads.  You will find the additional money spent over Vortec heads (for example) rewards the end user with a really nice set of heads having ALL of the needed features that the difficult to find factory heads should have had anyhow.

This will  include multiple bolt patterns for valve covers, early intake bolt pattern, screw in studs, guide plates, EXCELLENT flow characteristics, high efficiency "modern" combustion chambers and hardened exhaust seats.  They also come with one piece stainless steel valves and various spring options with excellent retainers.  They also have combustion chamber sizes in many offerings so one can attain an "optimum" compression ratio based on the CID and piston being used.

The very WORST aftermarket heads are at least as good as or better than the best factory heads in terms of port size and flow.

My favorites are the SR Torquer and Sportsman heads, but I've assembled a good many SBC engines with similar offerings from other vendors and most have been very good to excellent.  I've had to toss the springs a few times finding them too stiff for my liking, but overall most have been fine.

I still prefer to buy them bare and install my own components.  Ups the cost slightly but for sure you know EXACTLY what is in them, and with a little research one can source out everything and not break the bank in the process.  Also consider that with any mass produced part from any supplier, they may be areas that need attention.  Starting with bare heads I can buy good valves for them and check the fit at the seats, then put good PC seals on them, custom springs for what I'm doing, good retainers/keeps, screw in studs, guide plates, etc.

Anyhow, that's the basic lesson on SBC cylinder heads even though I only scratched the surface on the topic.

I'd add here that I've built more than most who will read this, and dyno most of them, then follow up with drag strip numbers.  If anyone needs any more details or advice, etc, feel free to PM me on the topic......Cliff

PS:  due to time/space I left out quite a few factory casting numbers made that were good to excellent, and just focused on the ones that are the most common to find at slap meets and such.....

PSS: also consider that when it may appear that I'm "bashing" 882 (and similar castings) that those heads were placed on engines with pathetically "low" compression ratios, so they aren't going to do much anyhow, and tiny little cams with retarded lobe positions, tons of emission devices, CAT's, and carburetors that were set up too lean anyhow.  Even with that said the only thing I use 882 castings for are door stops, as there are just so many better choices out there it makes no sense to start out with the worst of the worst for an SBC engine build....

olnick:
I found a set of "186" date code a.3.9  Would they be worth the effort?  I do believe they have the bolt holes in the ends.  excellent price as well! thought I would check prior to purchase.
they are 1.94/1.5 valves.

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