[Herb Hagan]

Aaron,
That was another aluminum head option I was discussing w/Cliff @ Norwalk. That is why I decided to stick with a PROVEN combo for now and picked up Jack's old top end from Wayne Garrison. Jack has run 8's N/A (tube chassis) and Wayne has run 9's N/A (Back half). The new motor project will be 500+ CID and will definately need a good flowing set of heads.

Herb

[GTOGEORGE]

Brian has a point! I think it's important to get the middle exhaust valves away from each other. I've aways said someone should make an aluminum high port RAV head! I would be the first one in line.

[bmpmdf]

Brian, The closest to that is the LS1 thru LS6 engines from the gm guys which is nothing more than a refined fuel injected Ford Winsor head. But each port can be made exactly like the one next to it.

[Tom Vaught]

Ideal head would be (Front of engine left side) E-I, E-I, E-I, E-I, with the drivers head).

When you install the head on the passenger side it would be from the front of the engine going to the firewall) I-E, I-E, I-E, I-E.

This puts the chambers in the right spots for the piston locations. Even though the Number #1 cylinder is specified as such on the Pontiac engine on the drivers bank, the actual most forward cylinder is the #2 cylinder on the RIGHT side of the engine. (like a Ford).

George,

You can have your Ram Air V aluminum head today (if you buy a Ford Tunnel Port DOVE ENGINEERING) head and move one head bolt in the head very slightly. All of the head bolts except for one will go right into the Pontiac block.

Mill off the material necessary on the exhaust to have your HIGH PORT exhaust (Ford racers have done that for years), build up the port shape you want, and get your shaft rocker system from T+D.

Once the intake is created (with a blower engine) no one could tell the difference from a Pontiac Ram Air V head either.

Tom V.

[lugnutt]

Not to start an argument, but how would it be a pontiac motor?
New block, new head, new intake? What left. I know the eternals are the same but what makes a "pontiac" a pontiac??
My as well just build a world products motor.
Oh, let the arguments begin!

[Robert C.]

A Pontiac is still a Pontiac when you can take any stock part and bolt it on in place of a after market part. That is what AllPontiac see it like, when making a part.

The only thing that we make that is not a Pontiac part, are the girls that buy our cloths. ha ha Girls are like Pontiacs, They look good, smell good and ride good. But you have keep working on them to keep them in top shape.

[Rob]

Ken I have no doubt that there's a lot of people that can build a competitive motor. Joe is likely one of them.

My point is, the DCI head is very close to the Wenz Super Chief(at least the one at Nowalk this year) so you're likely not gonna blow the performance out of the water. Need to stay above 2hp/cid and run faster than Scott -it's a tall order(and 2004 records, no doubt 2005 will find them improved again). We're all finding ourselves moving into classes...Pro Stock, Pro Modified, and 10.5 tire guys are probably going to be the big three.

I'm all for any competent company producing Pontiac cylinder heads, even happy with anyone giving us something close. I think we will all see Bob and Frank take the SC type head past where it is right now and hopefully increase production. The Pontiac is a Tall Deck, Mid-large size bore engine and the lifter bores are set up for inline wedge type heads. We are racing the fastest inline valve cylinder heads in the world. That makes them all resemble wenz superchiefs.

As far as different designs for new pontiac heads, In my opinion the best possible is one that will have the biggest Intake Valve and compareable runner. The canted valve head would require some fancy lifter bores(well maybe not require) and the RAV has pushrods going through the middle of intake ports. Hemi is probably the best design for moving the most Air and Fuel, but block clearance for pushrods and making a valve lift hi and big chamber volume make them less desirable for NA engines.

My post took a long time to type! I Agree with you completely Bob!

-Rob

"Big Valves, Big Lift, and Big Cubes rule all; ok atmospheres and cold O2, but that's not ON MOTOR!"

[NHRASuperStock455SD]

Yes there is a possibility of new RA-V heads. We ran RA-V heads in our NHRA 69 TransAm in 1982 in A/Modified Production at 3450 lbs and it went 147mph.

However, that was the same year when NHRA allowed to our surprize the new alum small block heads.

There was no way for a production head to compete with the 300 cubic inch small blocks after that. The National record in A/MP went from 9.41 to 8.92 the next year.

The Super Chief heads with our few modifications
show very real peformance in the ability for Pontiac guys to compete in Competition eliminator in NHRA. We got 427 cfm with a 2.3 with a special designed and improved combustion chamber. Our next step was to go with a 2.4 valve with some special work, so we can compete with the B-1 Mopar heads.

It is definitely a great and exciting time for Pontiac racers. :-)

Lynn McCarty
CMI Motorsports Inc

[Brian Baker]

Lynn, I assume those figures are with a 4.25" bore? This raises some question I'm pondering.

For years it has been generally accepted that 4.25" would be the "standard bore" to gauge head flow. Now that we can have bores much larger than this (up to 4.400" with the iron IA-II?), do we throw these figures out the window if building such a larger bore engine? Or do we stick with the 4.25" as an accepted "yardstick"? If we didn't, I could see the confusion creeping back in that was prevalent when 4.25" began to be the accepted "yardstick", as a 300-cfm head on a 4.25" bore would certainly flow less on a smaller bore. Maybe I just need to take some Motrin?

[NHRASuperStock455SD]

Brian,

You are absolutely correct. Just goes to prove that Pontiac guys are some of the smartest guys around. We did do our flow numbers with a 4.35 I believe it was.

If you take a Pontiac cast iron head, like my 455SD block that I run in super stock, and put the OEM SD head on it, and look up the bore hole backwards, it will frighten you to death!!

It makes the valve shrouding issue very apparent. This is with a 4.215 bore and a 2.11 Valve. The Pontiac engineers were smart about notching the blocks for valve flow.

Our next step is to go to 4.223 on the Super STock stuff. The Chevies are ahead of us on this one because they found out a long time ago that the SBC with a 1.88 intake doesnt run that much slower than the 1.94.

With the Wenzler heads it is exponetially exacerbated by the valve spacing when you try to go to the larger intake valve. So we have redone the valve spacing.

Even with all of these techniques, it still requires a 4.40 bore (my opinion)

We also are looking at head placement to maximize those shrouding issues.

When we take the next step to the 2.40 valve, it will be very interesting if it can be done at all. We are still working on it.

[crossbreed455]

looks like the car is twisting alittle ?????

mike m.

[NHRASuperStock455SD]

Yeah, the torque and the heavy rotating weight plays havoc with the 4-link. We have to run the heavy rods, heavy crank, so combined with the 610 ft-lbs, and 3270 lbs, those 1.29-1.32 60 foots take their toll. (Not to mention stock compression ratio, Cast iron SD heads, and a Q-jet)

WE were beginning to tear a 4-link bracket away. Didnt know it at the time.

Here is a picture if the link works. If it doesnt, then just go to AutoImagery.com and type my name in the search box, then double click on the pictures. You can also see other Super Stock racers like Don Kennedy, Peter Biondo, Steve Smith, John Angeles, Mike McKinney, Kenny Shawver.

US Nationals, Indy 2003

[grandville455]

Man thats TORQUE!!!!!

[Ron]

Hi Lynn. You run SD Heads...#16 SD Heads..and you get this level of performance out of low compression heads. WOW!!

[Brian Baker]

It's probably not as low as you think, Ron. If Lynn has taken advantage of all of the "maximum" allowed increases in bore/stroke, and "minimum" allowed decreases in chamber volume, it's probably somewhere in the 9:1 range.

Remember this head performed well from the factory in 73-74 in it's low CR form, so it is not surprising at all to see it run so well in Super Stock trim.

Good show, Lynn.

[Badbird69]

Check out the pictures of Michael Mans on that Indy site. Believe it or not, that firebird is powered by a 350 Olds motor with 1.88 intake valves. Amazing but true.

[Ron]

I was thinking that myself Brian. Still 9:1 is a lot different than say 11:1 or bigger. Still a pump gas type of motor and still impressive to me.

[Bill Bolin]

Gotta love those cars that twist!!!!

[NHRASuperStock455SD]

Thank you Ron, Brian,

Brian is correct, as we get to bore and stroke. However, the stroke hurts us more than it helps us.

A 455 piston speed at racing conditions causes the engine to "run out of breath". This limits performance.

It does not help us increase actual compression, just theoretical compression ratio.

We definitely need to increase the bore because of the valve shrouding issue, but not because of compression. The cubic inches hurt us more than helps us as the cylinder heads will not support it at 6000 plus RPM. Actually, a 4.00 stroke would make our engines faster as it would slow the piston speed down to a reasonable level for the cylinder heads.

The NHRA rules on the cylinder heads limit us. That is we arent allowed to increase the volume of the intake or exhaust ports. The numbers for the 455SD heads are 188ccs on the intakes, and 182 cc's on the exhaust. What we port out, we have to put back either by welding or adding epoxy with a few minor exceptions.

A low speed street engine cubic inches help, but at race speeds you have to have the head flow to go with it.

A good tech article to read about racing Pontiacs is on the www.wallaceracing.com website about this subject. Arrow down till you see "tech articles"

Lynn

[Skip Fix]

Lynn glad to see you posting here!