[Dragncar]

But tom s you did shrink the ports with epoxy and the flow went up right. I seen the pics of the heads and it looks like there was a fair amount of epoxy on the floor area.
I would bet a as cast RAV head on a 366 engine would indeed be lazy on the bottom end.
On the real 366 Pontiac engines with the 7.10 rods nice RAIV heads always beat the RAV heads. Just the way it was.
Those guys that guys that built that RAIV headed 366 on thier own dime for NASSCAR back in the 70s proved how well that worked. Came within a few tenths of the lap record for the track and got "good ol boyed" off.

[tom s]

FWIW,the "real" 366 engines were std deck engines,the reason for the long rod.My 366 is a short deck with 6in rods.The flo went up with good porting and not the epoxy.Also the engines were dynoed and driven with stock intake manifold ports with out any epoxy.Std ports only flo aound 315.My other set flo 400 at 800 with no epoxy.The reason my motors have worked well is because of the highlift modern camshafts.My 446 motor in my 69 GTO with COMPLETLY stock heads runs great.Drove it to a show today and screwed around with driving it,starting off in second gear with a M21 muncie with 3.55s in the back to see if I could use a 4 speed OD trans in this car.The OD trans is only avail with a 2.20 first.AGAIN!Before anyone bashes the so called lazy port,drive one,or 2 if your in the area.Tom

[Elarson]

When I was working on the design of the billet Ram Air V-based heads (for the Boss Bird), we flow-tested a stock RAV head. The big thing that came screaming out at us was that they needed a modern cam to perform to their potential.

FWIW:

Eric

[NHRASuperStock455SD]

Originally Posted by blaktopr

John, alot of it depends how the port is shaped. One person's "work" can be different from another. This includes how well the mixture exits the valve depending what is happening upstream.

blaktopr is correct here. Not only about swirl, but the non existence of swirl. What do you think a RA-V head has coming into the cylinder with a straight port? (Chew that one for awhile )

Recently we got a set of SD heads from a very good head porter. We had extremely good flow, but the CSA of the port was small. So, we sacrificed some flow in order to get that push rod area up to 2.7 square inches up from 2.35 square inches

This gave us peak RPM up to 7200 from 6700 and about 35HP average. What less flow and more HP? What a concept!

Many professional head porters go for shape first and flow second!

Lynn

[NHRASuperStock455SD]

Originally Posted by tom s

I am SOOOoo tired of everyone who have never worked on,never seen and never driven a V motor saying the ports are too big to drive.It is total BS!My little 366 engine with 274CC ports that flo 380@800 drive great.The dual plane intake 236-242 cam makes 446HP@5800 and carrys over 400lb TQ across the rpm range of a street motor on our 91 piss gas.FWIW,Tom

I agree with Tom. I had a RA-V 400 cu in with stock heads and intake and a single 4 and drove it around for 3 hours at the Dream Cruise in 1997. It drove like a Cadillac. (with the exception of the rear leaf springs)

Now.....that was a 4sp. However, just because we can make it a bit better doesnt mean we had a problem huge to start, it is just an improvement particularly for the automatic guys with no converter.

Just like something that stinks isnt necessarily bad to eat!

Lynn

[NHRASuperStock455SD]

Originally Posted by Elarson

When I was working on the design of the billet Ram Air V-based heads (for the Boss Bird), we flow-tested a stock RAV head. The big thing that came screaming out at us was that they needed a modern cam to perform to their potential.

FWIW:

Eric

::::: DITTO :::::

[BruceWilkie]

Originally Posted by BruceWilkie

Sounds like you want the look. Low rise intake, exhaust manifolds? If that sorta stuff including low speed performance are concerns, this head and other high flowing heads are probably the wrong choice. You cant have a head intended to make big power at high rpm on smaller motors or big power on big cube engines and expect great low end too.

Always choose the head thats best suited for your application.

I did not intend this to mean RA5 wont work at lower rpm. A head optimized for lower rpm range will work better at low rpm. A head intended for higher rpm power is better suited to do just that. If it happens to work acceptably at low speed thats fine. Some larger ports work acceptably that you would think otherwise.

To back what TomS is saying... One only needs to look at Fords 351c 2v head. The ports appear large but performance is zippy its generally a bigger port than a Pontiac d port for sure. The 4v versions were notably down in power at low speed. Same for std and CJ big block 429/460 fords factory iron(large and larger respectively) Part of the low speed loss was greatly attributable to cam specs! (and a choked factory ex port)

I agree cam profile can make a huge difference in how things behave.

FWIW I can drop a Pontiac 2.11 valve in the intake port of My Kaase heads with room to spare. It will still be driveable though. 413 cfm head flow, near .750 net lift cam with modest duration(288/298 adv 264/272 .050" .430 cam lift 1.83 effective rocker ratio) and modest overlap.(not a big cam duration for 528 cubes) My 528 is not yet complete but there are lower compression 521-557 ci versions with similar duration but shorter lift cams(Comp xr292 typical street grind) out there making 750 hp on the street and very driveable even with a victor and dominator and pump gas.(some on these boards would argue its not driveable) Pk power near 6500 expected. Im utilizing a tunnel ram and a pair of 750's and race gas or E85 due to my 13:1 compression. It will still be driveable and should still exceed 800 hp. Kaase says I'll have a fatter tq curve with the tunnel ram over the victor but smaller 750 carbs I'm using wont give significantly more hp over single domi victor combo. I could have opted for Edelbrock heads or Ford Racing SCJ with similar sized port slightly smaller bowls and valves. Id lose around 100 hp up top and gain very little above idle with the same cam.

The straighter the shot from the carb where the fuel is atomized to the center of the cylinder the less impact of supposedly lower velocity ports causing problems. There is more to velocity than meets the eye on a flowbench vs what is going on in the engine itself. Atmospheric pressure vs cylinder pressure, abrupt flow stops/starts from valve motion, reflected waves from those shocks, sonic wave reflections, carburetor air/fuel atomization, laminar vs turbulent flow, strength of exhust "slug" creating negative pressures behind it enhancing pressure differential as the intake opens at overlap, chamber purge of residual ex amount when the exhust closes at end of overlap. I hate to talk Ford on a Pontiac board but Kaase will tell you the flow number is merely the result of finding the best shape to meet the parameters. Much the same as my telling you folks you design a cam around an application not the LSA or .050 numbers.

The pics below are a Kasse p51 cylinder head 2.25/1.74 valve size. Top of the line in factory size/port location/bolt pattern Ford heads. (wimpy compared to pro stock pro mod heads available for the big ford.) These heads are intended for 429 thru @ 600 cid applications.

Valve im using for comparison is a 2.11" Pontiac.

I dont think Lynns revised RA5 head is too big unless your doing a Jim hand style tractor motor.

[Jim Robertson]

Any updates on the head castings?

[azbirds]

Lynn, What do you think direct injection would do for these heads, or any other Pontiac heads for that matter? Would it be feasible?

[NHRASuperStock455SD]

Originally Posted by Jim Robertson

Any updates on the head castings?

Jim,

We are pouring water jacketed prototypes next week. Working on a new patent for Clean Coal Technology, so I havent been keeping up on the boards, however we plan to get a couple of ports done next week via Tony Bishoff.

Side Note- I went to the Engine Master's Challenge on last Wednesday where Tony Bischoff shot out into first place. 435 ci LS-2 with a single 4 barrell. Everyone else had 2 x 4 barrels. He finished 2nd place by 1HP. The scoring was done with average HP and torque added together divided by the cubic inches.

We are doing Stacy's 428 this week for Vegas, and hopefully the RA-V heads next week. Tony is going to port the heads look at the tooling and tell us where we need to add alum for porting if any.

Lynn

[NHRASuperStock455SD]

Originally Posted by azbirds

Lynn, What do you think direct injection would do for these heads, or any other Pontiac heads for that matter? Would it be feasible?

My son is working on the Direct injection for the RA-V stuff. I can tell you this it is awesome. We had a complete kit for a RA-V but we sold it, I wish I didnt.

Lynn

[Stuckinda60s]

Lynn:

I don't know if this question's been asked or not, I've only read the first 30 or so postings. I apologize if it has.

Do you have any projections on what kind of compression ratios you can run on pump gas? The reason why I ask is because your chamber design looks like it would support some pretty high ratios. They look similar, while bigger, than the ones built for Fords and Chevies by, I believe his name was Fueling. They were capable of some really high ratios.

[NHRASuperStock455SD]

Stuck,

First of all I gotta tell you I love your screen name.

Compression is a combination of a lot of factors. Static compression ratio is just one of the variables. For example, we all know that the more intake fill you get from cam, intake flow, intake velocity, intake tuning, exhaust tuning, depends on the actual compression of the motor.

RA-V's even though had tons of intake flow, if the heads are too big, then velocity suffers and the net gain is sacrificed. What many people dont realize is that a RA-V has virtually zero intake "choke" limiting RPM and HP capability. This is the major component limiting HP. It is also the major component that makes Pontiac run in a street engine due to maximizing the velocity.

We hope to hit a better target around 455 cubic inches. It is going to be closer to making power like a square port big block or Hemi than like a Buick Stage I or a 455 Olds W-30.

If we can build in as much flexibility as possible, then the heads become not the limiting power of a Pontiac. Smaller engines (400 cu in or below) depending on how they make power might need to epoxy the intake ports depending on where they want to make power. We know this that the velocity of the new alum heads will be much better than old.

On the other end, we have a huge ability to gain CSA in porting for the larger cubes.

With all that being said, static compression ratio depends on total cylinder compression not static compression ratio. Yes it significantly contributes, but it depends on all the other design factors.

Tony Bischoff got second place in the engine masters tournament week before last. (average HP + average torque/ cubic inches) Those engines are pump gas engines. Tony will be a great help.

It was also very nice to get a call of support from George DeLorean the other day and the guys at Dart.

Lynn
[email protected]

[NHRASuperStock455SD]

Got pictures of the block @ BES for the RA-V street motor project. It is a beautiful passivated gun metal gray color after shot peening (my cell phone doesn't do justice.) Just a standard 455 block with 4 bolt SD caps to be installed.

Main cap on top to be fitted. Just wanted to advise of progress. It is going together very nicely with just regular "off the shelf" stuff.

I showed RamAir-V heads to Tony Bischoff today and he is wondering if the regular street motor makes more power than mine or Stacy's SSer?

That might make me sad and happy at the same time?

Lynn

[ponjohn]

Originally Posted by NHRASuperStock455SD

Got pictures of the block @ BES for the RA-V street motor project. It is a beautiful passivated gun metal gray color after shot peening (my cell phone doesn't do justice.) Just a standard 455 block with 4 bolt SD caps to be installed.

Main cap on top to be fitted. Just wanted to advise of progress. It is going together very nicely with just regular "off the shelf" stuff.

I showed RamAir-V heads to Tony Bischoff today and he is wondering if the regular street motor makes more power than mine or Stacy's SSer?

That might make me sad and happy at the same time?

Lynn

Lynn,

Is that a freshly cast block or OEM?

[NHRASuperStock455SD]

Originally Posted by ponjohn

Lynn,

Is that a freshly cast block or OEM?

OEM Pontiac block 1976. This crate motor will be a street version with all regular stuff. We are going to see what power we make with just standard street stuff done as economical as possible.

Stacy's 428 OEM block and crank w.Q-jet produced on the dyno today mid 700HP range and goes 8700 through the traps. Bearings came down perfect.

I plan to include this crate motor in my list. You either send me a block, pay a core, or buy an after market block as an optional adder.

Lynn

[440GP69]

Forgive me for being confused Lynn, Are you making an Aftermarket Pontiac Block or Not? and when are you taking deposits on the 5 heads? Thanks

[NHRASuperStock455SD]

Taking deposits on RA-V heads without water jackets!!!!!!

Taking deposits soon on water jacket RA-V heads. Yes we are doing a RACE BLOCK ONLY! There is already two very good after market blocks that I need not duplicate.

My block will not be compatible with street engines, however invaribly someone will build a complete RA-V race engine and put it in a street car. ;-)

I hope to have a 4.550 bore RA-V race engine done by the end of the First Quarter next year. The RA-V street engine will be done this year. We will first build with stock heads, then with ported heads.

Lynn

[Ron H]

Does the block have to standard? Can someone send a complete short block to be worked over?

[mysticmissle]

"I hope to have a 4.550 bore RA-V race engine done by the end of the First Quarter next year. The RA-V street engine will be done this year. We will first build with stock heads, then with ported heads."

woohoo thats awesome> i need to sell the mustang and get another pontiac to put a V motor in!
only way to get that big a bore is no water jackets right? thats why not a street motor? how bout on alcohol?