Inliners International Forums General Discussion Engines 292 head

Hi everyone,
I'm working on a 1981 292. The block is stock, but the head is from a 1967 292. This head has a couple burnt valves and I'm getting ready to take it off. I have a head from a 1970's 250 Mercruiser(165). Would there be any performance advantage to running this Mercruiser head? Or should I just have a valve job done on the 1967 head? I'm not looking to run drag races with this engine, but I'd like to have the best performance for my limited budget. Thanks in advance for any advice.

No advantage that I ever heard about.

If you want a bump in compression,install a small chamber 194 cylinder head.


MBHD

There is no performance advantage to the mercruiser head. If looking for stock performance at cheapest price. Put on whichever head needs the least work.

For best performance on a limited budget, install larger valves and port the head, If you want more power , even with a stock cam , then install intake port lumps too.

The 194 head is a waste of time. Tom

Can you explain to us why a 194 head is a waste of time?



MBHD

We have found with our extensive dyno testing of all the different valve sizes and lump/non-lump ports and small chamber vs. large chamber heads, that the small chamber head lost at least 10 HP minimum with every combo we tested, more on some. So the compression gain its felt doesn't justify the HP and torque loss that you also will have using this head....Thats one of those "untruths" thats always been told about those heads that needs to be exposed for what it really benefits a person expecting to use it. So don't always think that more compression = more HP!

That is very interesting...kinda like with a flathead I suppose where increasing compression decreases flow so you get gains and losses that don't always help. Yea for dyno!

The 194 head is NOT a waste of time. If the valve is unshouded the right way.When installing bigger valves in anyone of the heads, the valve should be unshouded. Stock valve for stock valve yes the bigger chamber head will flow better and needs less
work to unshoud a larger valve. BUT a 194 head can flow over 250
CFM with a larger valve. Porting a head is the same No matter
which that it is.
If you plain on useing the marine head have it TESTed I have found that most are pretty thin due to the salt water eatting away at the casting. my2cents would be use the head with the brunt valves But still have it tested.

Looks like Tom's tests with "real data" is going to put a lot of these "pissing matches" to rest !!!! Maybe not..a lot of people don't even believe their lying lying eyes..

I have no clue to what YOUR issue is scrapiron. I didn't or don't
see a pissing match as you put it. So your comment wasn't even
needed.And Just like this one it has NOTHING to do with any Tests
Or data.What Tom!!!!has done is good Info for a street or
hot streetrod daily driver.Nobody said anything differently.
And what tom did with the testing is Nothing more then what anyone else could have done. Or that hasn't already been done.
All he has done is pass the info along to other who have helped
Pay for what he wanted! to do.So in getting 200-250,300HPhas never been hard to do out of one of these L6 engines.
Finding combo(printed) data out there may be the only thing hard for most to find.
So if this is what you find/call a pissing match Then fine and
Dandy. I know how to wash my hands and walk away!
My2cent comments are Now Done.

larry,
I don't think that Scrapiron is directing anything at you or anyone else. Believe he means some people just won't believe the truth when it is in front of them, just as he wittingly said.

Larry and Hank,
This dyno testing has shown lots of stuff to me and yes it was and is still being shared with all contributors (if anyone is missed, let me know).
I ran a "194" head, prepped the same as all the other open chamber heads w/194 intakes, even opened up the chamber(same as open chamber around intake), conclusion was simply , power is down. Now maybe I did something wrong and am all ears. As of this time, I will not recomend a "194" head to increase power. Tom

I REST MY CASE !!!

I would ask that NO ONE leave this discussion. We are all here for the same reasons and many of you have knowledge the rest of us need. Our performance needs are as varied as the gasoline engine powered quest gets. I don't know of a 292 powered motorcycle but I wouldn't be shocked to find one. They, and their inline brethren, will be found all other forms of conveyance. There has always been quite a bit of "oral tradition" passed around especially about various full race applications. There have also been volumes written mostly about race motors. Except for Leo's book must of the info is 50+ years old and for a different generation of engines. What is happening here, from my view any way, is that Tom is attempting to sort out some of the commonly held beliefs using dyno data. As we all know each engine component of a modified engine must be matched to all of the others. Swapping major components on a short block in a limited time frame cannot give maximum results. We knew that going in. What we hope to gain here is a good look at combos that work. If something doesn't we can ask why. Wrong combo? Maybe? Piece of crap? Doubtful but maybe. The focus is streetable power and as e know there is nothing exact about the terms "street & driver". Filling the gray area between Grandma's Biscane and Douglas's Opla is going to be a vast undertaking. It begins by getting Tom's results in a form that can be reviewed by all. For some that will be it and they will trot off to to the equipment mongers with confidence and written "proof" and purchase the parts listed and forever think by bolting them in place they are duplicating Tom's results. OK by me! Other's will say," Wait a @#&$'% minute that worked for me!" and they will argue their point till their dying day. A few will see a discrepancy and their nature will not allow them to ignore it. Hopefully those guys are contributers to THIS bulletin board and they will lead us to more testing and problem solving and add their results to the information HERE. Some are going to have their beliefs put in doubt and some my get their automotive toes stepped on. I doubt if Clay Smith, Isky,and Crower always agreed. First one to the finish only wins THAT race!

Compression vs Flow: In the 90s Kenny Kloth ran a '49 Merc at Bonneville with a Flathead V8 that set records in two classes and had a best run of 148mph with 5.8:1 cr!

Sorry for the rant, Beater

I just can speak from personal track experience. C.I.,is 254

When I had the large chamber head,but milled a bit I had approx 10:1 compression & ran 14.3-14.5 in the 1/4 mile.

I then installed a 194 small chamber head w/smaller valves than the larger chambered head 1.85" as compared to 1.94" valves.
With this head my compression went to 12:1 Also had 220-225 PSi of cranking pressure,,which is pretty high.

With no other changes other than the cylinder head swap I ran 13.8-13.9 in the 1/4 mile. I would not say the HP really jumped up,,mainly the torque.

You could really feel the torque output increase throughout the entire RPM band. It just ran so much crisper everywhere!!

I never dynoed the car with this engine ,but both combos where equily tunned.

The cyl heads did not have lump ports,but had mild porting on both heads. BTW,,if you go too big on the porting,,,mostly on the entry way of the intake port you lose too much velosity & therefore loose a lot of torque.

The main thing you normally get form increased compression is more torque,,,not so much in HP if cylinder heads flow numbers being the same.

My two cents & personal expierience ,take it for what it's worth,,but @ least it was track tested.

BTW,,this was my daily driver w/12:1 compression,that I ran 92 octane.

MBHD

"BTW,,this was my daily driver w/12:1 compression,that I ran 92 octane."
That is interesting, What type of ignition were you using? How much advance? What is the elevation where are?

I was using an HEI w/an MSD box. It has been a while since this combo ,,but IIRC the timing was set to 34 degrees total.

I ran a lot of initial timing w/not much advance,,somewhere about 22-24 degress initial & the rest in the advance.

I owe all this mainly from haveing a 0 to positive deck of .003"

Elevation @ the track was 3000-3500 ft,depending on conditions.

MBHD

"Elevation @ the track was 3000-3500 ft,depending on conditions."
That was snow depth before "Global Warming"? Just kidding.
The .003 positive deck actually puts the piston into the gasket space? Wow! One thing for sure success is about attention to detail. Thanks, Tom

Very interesting 292 dyno testing result concerning the higher compression ratio 194 cylinder head yielding less power. In basic four stroke engine design, compression ratio sets the thermodynamic (also personally called thermogoddamics at times) limit on engine efficiency and power. Of course numerous other factors are involved before that limit is reached, such as inlet and outlet flows, combustion surface area, detonation, mixing involving swirl and swish, flame travel, spark intensity, etc.

Tom Lowe's and Twisted 6 Larry's information are both valuable. The standard taken-for-granted modification of installing a cylinder head to raise combustion ratios for increased power may require additional special cylinder head modifications to work in our engines.

How do the BSFC (brake specific fuel consumption) figures compare with the 194 head? Tom Langdon can probably add some insight here, with all of his years dyno testing for General Motors.

Hopefully this discussion on the 194 head will be carried over to the 292 dyno testing thread.

One thing that has been thought to be the likely source of the power loss, is the closed chambers inability to breathe as efficiently as the open chamber head. Even though both heads had the intake valves unshrouded the same amount with the same tooling. It has been no secret in the Big Block Chevy world, that the open chamber version of this engine families cylinder heads are vastly superior in breathing, compared to its closed chambered brothers. This is perhaps the reason that many of the aftermarket cylinder head companies like Brodix, Dart and others only offer these heads in an open chamber design, even though a huge gain in compression is seen with the closed chamber. That isn't to say that a closed chamber style head can't still make some good HP and torque #'s. But when repeated dyno testing shows evidence that reveals actual data contrary to an age old belief that more is better, it should begin to be evident, that this old adage wasn't really true to begin with, and was just an assumption based on "more is better" type of thinking. There is going to be in the very near future, not only a magazine article or two revealing some of the dyno data from all this testing and the power potential of the 6 cylinder, but also at least(2)new "How To" books and power manuals that will be very complete, precise and accurate on how to prep and build your Six. They will also reveal a lot of never before told "trade secrets" and "tricks of the trade" specific to these engines, so there will be no misconceptions about what will or wont work, and hopefully further clearing up many other beliefs that aren't correct. I also have developed a flow system that will allow you to "see" the airflow of any given cylinder head to evaluate flow patterns in the ports and chambers to further reveal both cylinder and chamber shrouding that a flowbench won't tell you, just for these types of scenarios. Thats one of those things to be released in one of the books. There are also a lot of behind the scenes development taking place as well that hasn't been told yet, but will soon be very helpful to many members here. Stay tuned for the 250 dyno testing coming up at the beginning of the New Year....

I will be interested to see if the small chamber head behaves the same way on a 250. Will the same components stack up the same way?

I think that with additional chamber relieving the small chamber can be made comparable to the open chambers breathing capabilities, just as in a BBC. But for the person contemplating the swap, it just means more additional labor and $$$$, just to end up at the same place the open chamber head is to begin with. So dollar for dollar, it will not be a wise choice from either the financial standpoint or performance one as well.

CNC-Dude, any time forecast for the distribution of the magazine articles and the two books?

Winter, the article(s) are slated for probably the most "top shelf" car magazine there is, and after all the data is compiled and put into text form, they usually have a 2-1/2 month lead time before it appears in the magazine. As for the books, I currently have a lot of the data already in text form, and am scheduling the photography in the next several weeks. Instead of having generic pics, I will make sure all of the photos are of actual Chevy 6 blocks, cranks, heads and related components. Once its all complied into a ready to print PDF format, its only about 6 weeks out from being printed. The second book will be exclusively about head porting for the siamese heads, and will be strongly involving Superflow throughout the entire book. They will be introduced first on here to give all the Inliner guys an opportunity to acquire them first, before being available elsewhere.

CNC-Dude:

Count me in for both books (and maybe a second copy of each for my son).

I hope some time in the future, you might consider a book on the "big" Ford six (with plenty of input and help from the guys in the Ford camp).

Russ

Glad you asked Russ, I have already been in contact with Gary Isbell who was a long time Ford 300 NHRA racer in several of their eliminator classes. He has sent me a lot of photos of his car and engine shots. He only lives less than an hour south from me, and he is planning on us meeting for a more formal sitdown in the near future. He also tried the 351C hybrid head on his 6 cylinder engines back in 1973, and was a true pioneer along with other Ford racers in that same time period. It should be interesting. Cotton told me to contact him, because he purchased his first Chevy II race car from Gary in about 1970 or so. Cotton told me that Gary was one of his all time most favorite competitors to race against, and said he is an all around great guy. In the several phone conversations I have had with Gary, I can see how Cotton thinks so highly of him, and I am anxious to be able to meet with him. I will keep everyone posted about the books, so don't worry, all will be given an opportunity to get one. Since I will own the publishing and printing rights myself, they will never be out of publication or print, so hopefully they will be around for a long, long time for many to enjoy and reap the benefits of them.

CNC-Dude:

GMC, Chevy, Ford, Mopar, AMC/Jeep, or ???. Four, six, or eight cylinders. If you put together a book on any (or all) of these inlines, count me in. Any good (inline) information on one brand should have at least some application on the others. Besides, my library is nowhere near full!

Russ

Russ, there is a vast interest in the inlines, thats for sure. I plan to include some one-on-one interviews in the books with several well known racers that have raced and accomplished great noteriety with these inline engines, so that in itself will make the books a little more personal and down to earth. I think tlowe has a book or two up his sleeve as well, so before long there will be a lot of good and informative inline performance "How To" books and manuals for prepping most any Chevy 6 engine from stock to 600+HP and beyond. So stay tuned....