logo
12 Port News - Features
12 Port History
Casting Numbers
Online Store
Tech Tips
Become a Member
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
1. who has done this and would be interested in making one for me?
2. what kinda price would you consider fair for this type of job?
3. would it be reliable enough for a street car?
4. pros and cons.

I was inspired by Jevan Dalla Valle 7 second inline 6 Chevy Opala

Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
This is for a Gen-3 250, etc?
Why this instead of an available 12 port head?

Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
Originally Posted By: panic
This is for a Gen-3 250, etc?
Why this instead of an available 12 port head?


It would be for a 292, aren't the 12 port kinda hard to get with a waiting list ?

Unsure what they cost but probably more then I'd like so they are an option

Joined: Sep 2008
Posts: 3,673
Likes: 42
1000 Post Club
****
Offline
1000 Post Club
****
Joined: Sep 2008
Posts: 3,673
Likes: 42
Several issues make it impractical, even for the most extreme builds.

1) A better 12 Port head already exists over what you would gain from trying to cobble V8 heads together.
2) Drilling the block to accept the V8 head bolt pattern weakens the block too much, and has been the cause of engine failures by those who have done it at that level.
3) The word "custom" usually doubles or triples the cost because all other associated components like pistons, intake, headers, valve cover and other specialty parts needed to make the V8 head fit the 6 cylinder block will also be required to be "custom". "Custom" = $$$$$$
4) See #1



Class III CNC Machinist/Programmer
Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
I have never heard to block needs modified for these style heads.

I feel confident in my ability to fab headers intake and covers.

The 12 port head is also custom.

I appreciate your input tho, thank you.

Joined: Sep 2008
Posts: 3,673
Likes: 42
1000 Post Club
****
Offline
1000 Post Club
****
Joined: Sep 2008
Posts: 3,673
Likes: 42
Originally Posted By: Shiozaki

The 12 port head is also custom.


Not really, custom hints at a one off concept, and all the 12 Port head components are production parts and not one off's, and are sitting on a shelf waiting for you to buy them. They have been figured out and proven for over 30 years, and is "store bought", as are the other components required to use it. The cost to purchase a set of V8 heads that are even capable of out flowing and out performing the 12 Port head to begin with will cost more than buying a 12 Port head($3500 fully ported), then you have to saw them apart and reconfigure them to re-weld them. Do you want to saw up a set of heads you have $3500+ invested in? If your truly wanting to mimic the performance you mentioned, that is just the starting point and you haven't begun to prep the shortblock to handle that kind of power output, which will easily cost as much or more than the heads will cost.



Class III CNC Machinist/Programmer
Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
The SBC V8 feature that makes its heads semi-practical is the fact that the bore pitch (distance between adjacent cylinder centerlines) is the same for the later L6* and V8 at 4.40". The bolts are way off.

* this is why the 235 etc. isn't so simple. Nothing else has that staggered bore pitch (although many older engines have stagger including the slant 6, GMC, Ply-Do, Pontiac, etc.), so in addition to all of the other work you also need either surgery just to move the chambers over the cylinders, or partially shroud the chambers.

Joined: Sep 2008
Posts: 3,673
Likes: 42
1000 Post Club
****
Offline
1000 Post Club
****
Joined: Sep 2008
Posts: 3,673
Likes: 42
Kudos if you can do the bulk of this yourself. Just be aware that most all hybrid head conversions rarely see completion. Just go in with your eyes wide open. Good luck!



Class III CNC Machinist/Programmer
Joined: May 2009
Posts: 493
S
Contributor
*****
Offline
Contributor
*****
S
Joined: May 2009
Posts: 493
Seems to me you might be able to find a damaged set of aluminum SBC v8 heads for cheap as a starting point. You only need six good chambers.

I would love to see photos of this conversion in progress. All I have seen is what Leo S. put in his book.

I am all for projects like this if you can do most or all the work yourself. If you have to pay someone, maybe not such a good idea in my opinion.

Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
I'm sourcing two aluminum vortec heads for this conversion, these heads are cheap and readily available.

I've been talking personally with valle, he uses a stock head with out the bolt in lump for use in his 7 second car.

Making 1000+ HP like him isn't my goal 600whp would be enough, if I can't find someone interested in taking on the job I just my go stock or the 12 port.

I appreciate all the input.

Joined: Sep 2008
Posts: 3,673
Likes: 42
1000 Post Club
****
Offline
1000 Post Club
****
Joined: Sep 2008
Posts: 3,673
Likes: 42
I was going to also say to not sell the lump head short because it has a lot of potential. You also seemed to imply he was using Chevy V8 heads welded together because you said you were inspired by his build. If he is using a lump head, why not just use a lump head yourself. Very little custom parts would be required then.



Class III CNC Machinist/Programmer
Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
Well I said he's using a stock head without the lump.

I was inspired to build a inline six because of his record, not copy his build.

Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
600 hp with the stock head?
Would that be nitrous, turbo, or supercharger?

Joined: Jan 2002
Posts: 395
M
Contributor
*****
Offline
Contributor
*****
M
Joined: Jan 2002
Posts: 395
I would not use a vortec head because a well prepped lump port will out flow it and bolt on. If I was going though the trouble I'd try a LS head first. The main issues with v8 head all the work involved and a shop or someone to help my be difficult. On a build like that there will challenges at every turn. We have been down that road many times over. The engines in Brazil are simple air pumps with a lot of Methonal,nitro and a huge turbo for boost. I have also spoken with the guys down there in Brazil.

Joined: Oct 2007
Posts: 5,041
Likes: 51
1000 Post Club
****
Offline
1000 Post Club
****
Joined: Oct 2007
Posts: 5,041
Likes: 51
An option mentioned in Leo's book but not given any coverage was the use of two 181 MerCruiser 4 cylinder heads. It would not be cross flow but it would be 12 port. There are a few head choices and it could work. The Siamese port issue would be solved. Most if not all head bolt holes wood line up. Once head was welded it would be nearly a bolt on with custom manifolds of course.


"I wonder if God created man because he was disappointed in the monkey?" Mark Twain
Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
I've been meaning to buy the book but havent yet, a more bolt on approach would be great, LS heads would also be great.

It be great if I could find someone wanting to do the work so we could hash out the details.

Last edited by Shiozaki; 01/05/18 04:08 PM.
Joined: Apr 2003
Posts: 1,541
Likes: 16
1000 Post Club
****
Offline
1000 Post Club
****
Joined: Apr 2003
Posts: 1,541
Likes: 16
The LS idea is a good one - cathedral ports flow like mad. Here's a write up on a Ford I6 with a hybrid LS head - EngineSwapDepot.

But you're into an experiment here - read $$. Should you find someone willing to undertake the prototyping - you'll have to bank roll the parts and the labor. And there is no telling how many times you'll have to try before you get a working engine:
2 or 3 blocks? You'll be experimenting on head-bolt boss relocation. You could hit water - you could have cracking when you try to torque . . .
2, 4, 6 heads? You'll be experimenting on where to cut - how to join the halves etc.

It's a cool idea for a project but it can't be approached as if one is just hiring a machinist to do known flat rate work.


Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
someone wanting to do the work

A lot of people want to do the work.
Exactly what work will they be doing (i.e., following your instructions)?

Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
The heads have been done before it isn't like I'm asking to explore the unknown.

And ls heads really weren't what I was shooting for.

Last edited by Shiozaki; 01/05/18 08:19 PM.
Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
Turbo

Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
it isn't like I'm asking to explore the unknown

Sorry, I don't agree. That tells you that it can be done. It tells you very little about how to do it.

Joined: Sep 2017
Posts: 209
Likes: 2
M
Contributor
Offline
Contributor
M
Joined: Sep 2017
Posts: 209
Likes: 2
I waited and talked to Mike Kirby (Sissell) for about a year for a 12 port head ($3500). You still have to buy manifolds. He told me he had 5 castings left but it was questionable if any of them were good. I will be running a 4-71 blower. I am having Gaerte Racing Engines build the 292. I spoke to Tom Lowe about a lump port head and he told me that Gearte would be better suited to do the head for what I am doing. James Larrow is doing the blower (jj inlines) and also a serpentine harmonic balancer for the accessories. Crank fired ignition and external oil pump driven by blower belt. 3 X 2 bbl Roch carbs. Tremec TKO 600 and Frankland quick change rear end. Goes in my 53 Chevy pickup. Good luck and go for it. It's the journey.

Joined: May 2009
Posts: 493
S
Contributor
*****
Offline
Contributor
*****
S
Joined: May 2009
Posts: 493
I don't know if right or wrong but driving the oil pump with the same serpentine as the blower raises question in my mind.

Blower drive is high power, say 50 horsepower or more. Oil pump has much less power requirement. Will the oil pump drive compromise the blower drive? High power drives are sensitive to geometry, slack versus tight side, pulley wrap, backside idlers, etc. are considerations. If you throw the blower belt you lose oil pressure. Again, not saying good or bad, just asking the question.

Joined: Apr 2003
Posts: 1,541
Likes: 16
1000 Post Club
****
Offline
1000 Post Club
****
Joined: Apr 2003
Posts: 1,541
Likes: 16
Originally Posted By: Shiozaki
The heads have been done before it isn't like I'm asking to explore the unknown.

And ls heads really weren't what I was shooting for.


I searched for a thread that I recall from 10 years ago - found it just now - High Performance: Hybrid Head for a 250 circa '08

The poster was pursuing and at least one response indicates success but not without challenges.

Good Luck and keep us posted.


Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
Question I don't remember addressed before: w/r/t welding the 2 (partial) V8 heads together.

How does the water in the rear head's passages travel forward across the weld? Do front 3 to rear 3 water gallery ends seal face-to-face without any leaks?

Joined: Sep 2017
Posts: 209
Likes: 2
M
Contributor
Offline
Contributor
M
Joined: Sep 2017
Posts: 209
Likes: 2
The blower belt is 3" wide. Could run 2" but they went with 3". I leave that up to the experts. There is a sensor that shuts the engine down if oil pressure is lost. Carry a spare belt under the seat.

Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
3" of course has better "traction" and longer life with the same load.
Disadvantage: greater bending stress on the crank nose.

Joined: Sep 2017
Posts: 209
Likes: 2
M
Contributor
Offline
Contributor
M
Joined: Sep 2017
Posts: 209
Likes: 2
They are making a billet crank.

Joined: Jan 2002
Posts: 395
M
Contributor
*****
Offline
Contributor
*****
M
Joined: Jan 2002
Posts: 395
Originally Posted By: mick53
They are making a billet crank.


Are they machining it in house or vendor?

Stock stroke?

We had Marine Crank in Cali do one for us and its a piece
of art. Hate to put in a motor and you cant see it.

Joined: Apr 2003
Posts: 1,541
Likes: 16
1000 Post Club
****
Offline
1000 Post Club
****
Joined: Apr 2003
Posts: 1,541
Likes: 16
Originally Posted By: MIGHTY6
We had Marine Crank in Cali do one for us and its a piece
of art. Hate to put in a motor and you cant see it.


I felt the same way about custom pistons from Ross - hated to stuff them in the bores never to be seen again . . .

Joined: Sep 2017
Posts: 209
Likes: 2
M
Contributor
Offline
Contributor
M
Joined: Sep 2017
Posts: 209
Likes: 2
They are having the crank made. Mcload or Mcmurry or something that starts with Mc I think. I don't know any specs on it. I build buildings so I just tell them what I want and they figure out how to get there. know it took 12 to 14 weeks to get.

Joined: May 2009
Posts: 493
S
Contributor
*****
Offline
Contributor
*****
S
Joined: May 2009
Posts: 493
I'm curious what your accessory drive looks like. Are you saying there will be oil pump, water pump, alternator and blower, all driven by a single 3 inch wide serpentine belt? Maybe I misunderstand.

Joined: Sep 2017
Posts: 209
Likes: 2
M
Contributor
Offline
Contributor
M
Joined: Sep 2017
Posts: 209
Likes: 2
The 3" wide blower belt will drive the blower and oil pump. That will mount in front on the harmonic balancer. I am having a custom serpentine belt harmonic balancer made that will drive the water pump A/C and alternator. I am installing electric power steering. The accessories will be standard 8 rib or whatever it is. The ribbed belt just replaces the v groove belt. Just like they make for SBC and BBC. The problem is I have to have all the stuff made custom because I'm not normal.

Joined: May 2009
Posts: 493
S
Contributor
*****
Offline
Contributor
*****
S
Joined: May 2009
Posts: 493
Gotcha. That makes sense.

Does the oil pump have stout enough bearings to handle the blower drive belt tension?

Joined: Sep 2017
Posts: 209
Likes: 2
M
Contributor
Offline
Contributor
M
Joined: Sep 2017
Posts: 209
Likes: 2
I guess so. I don't know a lot about it but these guys have been building race engines for 40 years or so. They used to build Greg
Biffles engines before he went to Rouch. I just happen to live 40 miles away and we know some of the same people. It took me a year to convince them to build my engine. I just have to assume they know what they are doing. They are even giving mr a warranty. They are making it idiot (that's me) proof with rev limiter and safety cutoffs for oil pressure and temp.

Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
Went way off topic lol.

Thinking of going ls heads, from what i was told, alot easier to make LA heads fit the block instead of making block fit your hybrid head.

Last edited by Shiozaki; 01/14/18 08:39 PM.
Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
I'll just leave this discussion to the experts, who always have time in their busy schedule to explain why I'm wrong.

Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
Have a nice day

Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
Why would I need a billet cam when all cams start out as blanks, it shouldn't be anymore then a custom ground cam I would think.

Joined: Dec 2017
Posts: 17
S
Active BB Member
OP Offline
Active BB Member
S
Joined: Dec 2017
Posts: 17
The Nissan and assuie hemi head do interest me, I wonder how they flow.

Page 1 of 2 1 2

Moderated by  stock49, Twisted6, will6er 

Link Copied to Clipboard
Who's Online Now
0 members (), 125 guests, and 27 robots.
Key: Admin, Global Mod, Mod
Newest Members
Hairyclive, THarper, crash, ocean1907, Jabez House
6,816 Registered Users
Sponsored Advertisement
Sponsored Advertisement
This Space is Available
Powered by UBB.threads™ PHP Forum Software 7.7.5