Later Heads On A Dauntless

I have several Dauntless engines and I want to up grade the heads with later 231 heads, I've read conflicting stories about the best heads to use and what years are the easiest. I was referred to TA Performance a while back since they had a V6 guru that had a good write up, no response. This will be for my '66 CJ 6 with Holley intake and EFI. I may do the same thing for the engine in my homebuilt skidsteer with a Dauntless and automatic.
If anyone has successfully completed a head swap and is willing to share their info I would certainly appreciate it I would need details like cooling passage mods, casting numbers for the heads used, and year, model etc. I haven't found anything in my searches, TIA.

 

I have heard guys on here stating that the oil passages are different. I have heard that the 231 heads flow better but will require some machine work to make happen. Thats all I know. I hope someone with more knowledge posts so I can learn too.

 

There are some performance books that may help you ... V-6 Performance: Pat Ganahl: 9780931472138: Amazon.com: Books

 

Later heads will not work................oiling passage's are different as will as the water jacket passages are different....................welding up the block or heads to accommodate either could be done with considerable time and machining but why?............................The later heads do have taller ports and flow better...............but were only talking 30 cubic ft.............build an even fire if you want to make more power.

 

I'll second Tim's suggestion on Pat Ganahl's book if you're serious about learning and building a Buick V6. It's very informative and a great resource. All you questions will be answered.

AFAIK, only the 231 odd fire heads will work on a 225. I think the change was around '76 1/2 or '77. Pretty sure the 231 was even fire by late '77-'78. Those heads won't work without major major rework. There was an interim head design that may work with less work but, scarce and hard to find. Easiest way to tell 231 OF heads from EF heads is the exhaust ports....low or high, respectively.


V-6 Performance: Pat Ganahl: 9780931472138: Amazon.com: Books

 

47v6, that is my understanding. Cooling and possibly oil passages.
Timgr/wheelie I've had Pat Ganahls' book for years, it does not answer any of my specific questions, that I can find.
Tarry99 If later heads absolutely won't work, why do people constantly refer to Ganahls' book about doing it?
I'm not arguing with any of you, I don't like an EF V6 engine sound or weak cranks( yes I am aware of GN Buicks) and, I am too deeply invested in OF v6's. I have two vehicles using them and three spare engines. Can anyone tell me how a Dauntless would know if it had EF or OF heads on it? I am looking for casting numbers of usable heads, pictures or diagrams of cooling/oil passage mods. I had an excellent write up from 15-20 years ago that was lost in a computer crash, and is NLA. IIRC a '79 or '80 model year head is the latest reasonably usable head.

 

http://nmr.mgh.harvard.edu/~reese/BuickV6CastingNumbersandInternalSpecs.pdf

 

225 dauntless and of231 (75-77) have entirely different oiling at the heads. 231 EF " low port" era heads are adaptable to the of 231 with minor work.

 

I never said it "absolutely won't work" I just made the point that welding up passages and then re-machining all the parts to get there in my opinion , had very little upside..........And yes , perhaps you could enjoy a little better cylinder head that flows a few more CFM but at what cost and benefit? 40,50,60 hours of welding and machining , pre & post heating the parts each time? And then needing to have all the surface's reground to flat once done.......chances are the valve seats would also need replacing , A new later manifold would also be needed to accommodate the ports and that manifold angle do to the removal of other metal may also need it's mating surface angle adjusted................I don't know what your time is worth $ but if that was being done by a competent machine & welding shop it's probably at least a 4k-5k upgrade in today's dollars!

The 225 Oddfire in itself is a unique motor with it's unbalanced firing ...........But, this was not built by GM engineers to enhance performance nor create a new state of the art engine platform.......the 225 came about as a quick & easy way using old components to rush a GM V6 into production on or about 1963.........I think we can all agree the 225 OF program was a success..........but later , GM finally took a look at the Illegitimate son they created and decided that and Even Fired motor would be better suited going forward to accept multiport injection & sequential timing as they did on or about 1978.

I get it that your invested in the Odd Fire's , but what I don't get is what you are trying to accomplish by sticking on the later cylinder heads? Is it just the hope that by increasing a few more CFM's , you think the Odd Fire will suddenly come to life an add 25-50 HP ? Ultimately without other adds to the OF motor like compression , camshaft , intake , exhaust and Ignition the gains would be minimal.

Don't get me wrong.........the Odd fires are an interesting motor but limited in many ways as to what they can make power & torque wise.........there are several folks here including myself that have invested many hours porting cylinder heads , decking blocks , shaving cylinder heads , raising compression ratios , changing rockers & trying different manifolds to extract a few more ponies...........quite honestly the biggest improvement to the Odd Fire's I've seen is to take that 52 lb flywheel off of it and replace it with a 30 lb...........along with a low granny transmission and suitable rear axle ratio's

The Buick even fire turbo block and the 25518445 head has a better starting platform to add Horsepower............and why is it , you think the split crankshaft is weaker as I have seen many of these turbo guys use them into the 600 + HP range and then only damage them when they beat the bearings out of them from detonation.

25518445 cylinder heads , shaved , ported with larger valves and seats added I have a ton of work into these..............compare the water ports to your Odd Fired heads & Block.

Some of the additional work required .............pouring hot aluminum into the heads to block the smog ports that hurt the flow.

 

Maybe I don't understand just what you're trying to determine. I found Ganahl's book very specific about what works and what doesn't as far as the heads go.

And I quote......" Unfortunately, '77 and later heads cannot be used on '76 and earlier blocks (without modification) because of a change in water passage shape and location...."

There are pages of info on the subject in the book-----pgs. 81-84.

 

Evenfire vs Oddfire
I believe the split crankshaft design to be slightly weaker.
But the strength difference must be a mute concern because you never hear of evenfire V6 engines breaking their crankshafst.

Some of the early Buick and Jeep Oddfires had crankshafts made from what GM called Armarsteel.
One of my Dauntless engines has an Armasteel crankshaft.
"Armasteel" was embossed onto the crank itself.
That engine was fully rebuilt after about 125K miles.
Amazingly the original Armasteel crankshaft was in like new condition after 125K.
All I had to do was polish the journals and the crankpins.

Heads
I expect the best heads for a Dauntless are probably the Buick 225 Fireball heads.
Those early 225 heads do not have the injector ports.
So gaseous flow obstruction should be less.

 

I am not arguing with any of you, I feel I have done my homework. My goal is/was to improve performance using stock parts to complement HEI and EFI already in place.
I have been researching and using Dauntless engines for about 20 years now. I have downloaded every article (200+)I can find on these engines. I have the Ganahl book, the Buick V8 and V6 Performance Years book and others. The engine in my CJ6 and skidsteer loader are are daily drivers and/or daily users. Since original Dauntless heads are not equipped with hardened valve seats and are somewhat restricted in flow, I would like to swap to later heads, I see no purpose in replacing the valve seats in a head with limited flow and smaller valves, when a better flowing head casting WITH hardened seats and bigger valves are available. I have HEI distributors on both engines, and Megasquirt on my CJ6, as stated in my original post.

What I am looking for is the info that was originally published by TA Performance regarding the required mods for installing '79 and later heads on a Dauntless, since I contacted TA and got no response, I thought I would ask here. I felt I was pretty clear with my request "If anyone has successfully completed a head swap and is willing to share their info I would certainly appreciate it I would need details like cooling passage mods, casting numbers for the heads used, and year, model etc. I haven't found anything in my searches, TIA." as written in my original post.

Wheelie: In the Ganahl book, page 82, in reference to '79 and later heads on earlier blocks it states "using a pre-77 head gasket as a template), you could probably make them work on an earlier block"

I have the ability to do the block/head mods myself, it is not rocket surgery, LOL.

If I was after a max effort, all out race engine I would put the money/energy into a Stage II TA.

My apologies for the confusion, TIA.

 

OK. In your OP, I found "later 231 heads" a bit unclear. Much more specific now with " '79 and later heads....." No arguments from me.

I am curious to see how your project progresses if you move forward with it.

 

I want to see the 225 powered skidsteer

 

me too.

 

Me 2.

 

Just for exercise and something to look at...........here is the early odd fire dauntless head on top and the later #8445 head on the bottom.......

 

Thx for the pix and casting numbers Tarry99, that will help a lot. I am busy tomorrow helping my son at a gun show. Current temp is a balmy .5 degrees, and we only have about 5 hours of daylight here in Alaska. Never uploaded any pix here but I'll try. I thought I had some pix but I can't find them tonight. Give me a couple days to get some pix.
To give you some details, odd fire, HEI, 3 speed automatic, driving a triple reduction chain drive to a common drive shaft between two '57 Chevy rear axles (the pinions face each other, with a drive shaft between the two pinions) I am in the process of adding the third stage reduction, slow going working outside and limited mobility caused by too many birthday cakes, 70 of them.