[dci]

The DCI Tiger heads are definitely bad a$$$ for an inline valve platform. I cannot wait to get my new DCI 5 heads on an engine to see if it's possible to raise the bar again. My new heads will definitely help distribute the heat more evenly over the head and should hold head gaskets much better. That by itself is a huge plus!!!!


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 heads !!!!!!

[ponjohn]

What's the availability on cam companies being able to supply RA5 cams?

[dci]

There are several cam companies that can and will make cams, but I am working with LSM.



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 heads !!!!!!

[tom s]

Have been getting cams from comp for years.Tom

[dci]

Tom I have used Comp as well, but I like LSM's lobe selection better. Unfortunately Pontiac's have a small cam core and it's really hard to get a decent lobe on them. LSM seems to have a pretty good handle on it though.



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 heads !!!!!!

[RAMAIR RICK]

Remember for the aftermarket crowd, me being one of them, I am going with a 55mm cam blank, which will open up the possibilities for everyone going down that path.

[RAIV-Z]

Originally Posted by RAMAIR RICK

Remember for the aftermarket crowd, me being one of them, I am going with a 55mm cam blank, which will open up the possibilities for everyone going down that path.

Hey Rick,

Standard firing order, 4-7 swap or LS1?

[RAMAIR RICK]

RAIV-Z, I do not know for sure if it is going to be the 4-7 swap, or the LS1, are they the same? I will Let Chris Uratchko make that determination. Whichever one is the best for my application. I will be surprised if it ends up be the stock Pontiac firing order. If Chris is looking around PY, maybe he could respond to that question.

[Tom Vaught]

LS and late Ford 302/351 are the same and the cam would require a double swap.

1-8-7-2-6-5-4-3. vs the stock Pontiac:
1-8-4-3-6-5-7-2

Easiest way to visualize it is shown above. Let Chris decide.

Tom V.

[RAMAIR RICK]

Tom Thanks for your knowledgeable information. For the Pontiac people here, would you from an engineering perspective, tell the reasons/advantages of having a LS/FORD firing order as well as the 4-7 swap? This much I do know, the Fords and LS engines do has a nasty/anger sound to them. I wonder if that is a result of the firing order or head port design. I am wondering how the New DCI - RamAir V will sound????

[tom s]

Would changing the firing order affect the way custom headers are clocked?Tom

[grandville455]

Don,
I have some more questions, Are there going to be drain back holes in the heads? Will there have to be a special stud girdle for them? You can run water thru them right? Factory crossovers work or is that a special item too if needed? Will anything need to be done to the bottom end to beef it up, lifter bore bracing? or is 6-6500 going to be a good shift point? AS for the exhaust, will the headers stay the same height from the ground now as a reg D Port like my KRE heads, I have limited ground clearance now(maybe 2")for driving on the street,lol

[Tom Vaught]

Originally Posted by tom s

Would changing the firing order affect the way custom headers are clocked?Tom

In one word, Yes.

Say you had a clockwise pattern on the passenger side collector with a 10:00, 2:00, 4:00, & 8:00 clock pattern.

Stock Pontiac firing order clocking would be: (Assuming the pattern started at 2:00)
Cylinder #2 would be at 2:00
Cylinder #8 would be at 4:00
Cylinder #4 would be at 8:00
Cylinder #6 would be at 10:00


Say you had a COUNTER clockwise pattern on the drivers side collector with a 10:00, 2:00, 4:00, & 8:00 pattern.

Stock Pontiac firing order clocking would be: (Assuming the pattern started at 10:00)
Cylinder #1 would be at 10:00
Cylinder #3 would be at 8:00
Cylinder #5 would be at 4:00
Cylinder #7 would be at 2:00


Again you had a clockwise pattern on the passenger side collector with a 10:00, 2:00, 4:00, & 8:00 clock pattern.

Ford/LS firing order clocking would be: (Assuming the pattern started at 2:00)
Cylinder #8 would be at 2:00
Cylinder #2 would be at 4:00
Cylinder #6 would be at 8:00
Cylinder #4 would be at 10:00


Again you had a COUNTER clockwise pattern on the drivers side collector with a 10:00, 2:00, 4:00, & 8:00 pattern.

Ford/LS firing order clocking would be: (Assuming the pattern started at 10:00)
Cylinder #1 would be at 10:00
Cylinder #7 would be at 8:00
Cylinder #5 would be at 4:00
Cylinder #3 would be at 2:00

Tom Vaught

[tom s]

Thanks Tom,I knew the answer and wated to throw it out there for people interested.Tom

[estep455]

Originally Posted by Tom Vaught

In one word, Yes.

Say you had a clockwise pattern on the passenger side collector with a 10:00, 2:00, 4:00, & 8:00 clock pattern.

Stock Pontiac firing order clocking would be: (Assuming the pattern started at 2:00)
Cylinder #2 would be at 2:00
Cylinder #8 would be at 4:00
Cylinder #4 would be at 8:00
Cylinder #6 would be at 10:00


Say you had a COUNTER clockwise pattern on the drivers side collector with a 10:00, 2:00, 4:00, & 8:00 pattern.

Stock Pontiac firing order clocking would be: (Assuming the pattern started at 10:00)
Cylinder #1 would be at 10:00
Cylinder #3 would be at 8:00
Cylinder #5 would be at 4:00
Cylinder #7 would be at 2:00


Again you had a clockwise pattern on the passenger side collector with a 10:00, 2:00, 4:00, & 8:00 clock pattern.

Ford/LS firing order clocking would be: (Assuming the pattern started at 2:00)
Cylinder #8 would be at 2:00
Cylinder #2 would be at 4:00
Cylinder #6 would be at 8:00
Cylinder #4 would be at 10:00


Again you had a COUNTER clockwise pattern on the drivers side collector with a 10:00, 2:00, 4:00, & 8:00 pattern.

Ford/LS firing order clocking would be: (Assuming the pattern started at 10:00)
Cylinder #1 would be at 10:00
Cylinder #7 would be at 8:00
Cylinder #5 would be at 4:00
Cylinder #3 would be at 2:00

Tom Vaught

good info thanks tom

[RAMAIR RICK]

Thanks Tom for sharing your engineering wisdom. With all of the different firing order options out there today, from an engine dynamics/performance standpoint, is there one firing order that is better then all the other V8's??? and if so is it worth going after??? Say the Ford/LS engine firing order or the 4/7 swap. Thanks in advance

[BruceWilkie]

There was an article a few years back in iirc a Hot Rod Engines edition... the way it read to me was 4/7 swaps sometimes help add a bit of higher rpm power with no trade off at lower rpm. Manifold design might impact whether you gain or not. The double swap(351W/LS) wasnt tested in that article. However they did mention GM's decision to use it was better load distribution on the mains(less load on #2). Perhaps that was Ford's reason to use it on 351W and then later on the 5.0. Better load balance can help improve harmonics which could maybe allow more rpm and possibly more power through less load on bearings.

I plan to use the LS/351W order on my build.

I'll dig the article out and scan it if no one has an internet link to it.

[dci]

There are oil drain back holes in the heads .500" inside diameter on each end like the factory heads. I have not considered a stud girdle, but I am working with Harland Sharp who are making shaft mount rockers. They will have 1.5 to 2.0-1 ratios available. I designed the head for Harland Sharp 1.65 roller rockers as a direct bolt on with guide plates. As for the water crossover, you can definitely use one cut off of a factory intake or the KRE crossover.I kept the factory location so the factory water crossovers will work. I am anticipating a conservative rpm range for the street version of my heads at or around 6,000-6,500. So I don't think that the bottom end will need much mare than usual for that application. I also think that the alternate firing orders will help with crank and block stress as well. I am actually building the header prototypes. So I am very aware of ground clearance and will do my best to keep the headers tight without rattling.



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 heads !!!!!!

[Bob with the 66]

Go Don Go!

Hopefully you will design a set of headers for a 66 GTO ;-)

I'm really looking forward to hearing some output numbers on engines running your heads.

Thank's for keeping this going.......
Bob,

[Tom Vaught]

Originally Posted by RAMAIR RICK

Thanks Tom for sharing your engineering wisdom. With all of the different firing order options out there today, from an engine dynamics/performance standpoint, is there one firing order that is better then all the other V8's??? and if so is it worth going after??? Say the Ford/LS engine firing order or the 4/7 swap. Thanks in advance

The ORIGINAL FORD "late" 302 and 351W used the Firing order known as the LS firing order (for the GM guys). Ford went with this firing order because it eliminated the "Double Hit" on the #1 and #2 Main caps with The right front cylinder firing and then the left front cylinder firing. By doing this the block and crank saw a lot less stress vs using the GM firing order.

On a Factory Pontiac block, in my mind well worth the effort.

With a All Pontiac Block that has had the front bulkhead strengthened over the years and steel main caps on all 5 positions, maybe not such a big deal on the block but the crank still sees the hit on two crank journals for the 6 then 5 and 4 then 3 with the LS firing order and 4 then 3 and 6 then 5 with the Pontiac firing order.

So to repeat again, the benefit is on the front main and the second main that see all of the normal stress in a normal pontiac.

I have inspected Factory 455 4-Bolt main blocks with cast caps where the #2 main was broken completely around the inner bolts, the thrust cap was broken 3/4 of the way from the block surface moving toward the windage tray, and 1/2 broken on the #3 cap, again the crack started at the block surface and was moving toward the windage tray.

So the #2 main cap sees a lot of stress with the factory Pontiac firing order.

If you have a supercharger belt applying force on the crank snout it is even worse.

Tom V.