RAV vs RAIV head comparison
 

I had an opportunity to freshen and flow some rare Pontiac high performance heads that were ported by two of the top Pontiac Cylinder head guys of the 80s-90's. The Ram Air V heads have a basic race port job. The two pair of 614 heads were done by the same guy. One pair are race ported and the other pair had a max effort street/strip port job.

The link will take you to more pictures and details. I don't think you need to be a FB member to read the link:

https://m.facebook.com/story.php?sto...ibextid=CDWPTG

Nice!


:)

Great flowing heads! :cool2:

I hope to switch to a RAV set-up one day (aftermarket, either DCI or McCarty).

Thanks for posting the side by side results. A great way to see how the different heads behave. The Ram Air V really comes on like gangbusters at high lift, just like I have seen on my bench. Keeps right on flowing until the retainer hits the valve guide. Push rod tube be damned, doesn't hurt much when the other heads are effectively done at .600 lift. Ram Air V exhaust is pretty bad as can be seen. On the plus side the configuration does allow for the best possible headers, especially when compared to D port exhaust. Great headers are desperately needed to take advantage of that high lift intake flow. Great stuff!

Thanks for show us this.
The RAV chamber looks more modern with the plug pointed right at the ex valve.

With the compression that the flat out racing Vs use even a 62 to 65 percent ration is not a limitation.

Just look at some of the SBC and SBF heads on motors making 900 hp and there still just pumping out Thru a 1.60” to a 1.65” exh valve.

The ratio needed changes very quickly above 12 to 1.

Thanks Mike.... The exhaust can picked up quite a bit by raising the port floor near the flange and additional porting. After doing some work on the intake port this head flowed 370 @ 750 and 387 with the retainer against the guide.... Like you said they just keep going!

YW... The 303 chamber was twenty years ahead of its time. This one was shaped a bit more than I would've liked. The virgin chamber resembles the chambers used in the Pontiac Pro Stock head. If you are really chasing power the 303 chamber is definetly an advantage.

Dead stock Vs with factory valves usually are about 315 or so at 600.Tom

Can you divulge the head porter ? I understand if you do not want to.
I remember Dan telling me about a pair of V heads he had on his bench that were the best flowing on the ex side of any Pontiac head he had seen. Almost 300cfm on the ex.
He said 300cfm was about it for RAIV heads but did get one pair to 310cfm.

I would be really cool to see someone with a worked set of 303 heads on a aftermarket block and see what it would make. Big cubes should help those heads work.

Thanks for the flow number here Paul.

The issue with getting the 4 heads Intake port to top 300 cfm is that there push rod buldge intruding into the flange area is more of a restriction then the D port heads since they where born with bigger diameter push Rods..
If you raise the roof up to near the top of the casting and carefully use a 1.86" valve bowl throat then 330 cfm @28" can be had.

But then if your not running a Intake for a high port head your dealing with a ton of welding and rework on your Intake to just match the new port height no less get the needed expansion rate on the way back to the Plenum.

Paul,
Thanks for the numbers. Going back in time. Do you happen to know the best that Mullins ever got from a Pontiac head?

Stan

Mendoza did my 303 heads,he reduced the port vol with splashzone.Tom

Mendoza did the V heads, Whitmore did both IV's.

I think 300 might be doable but awfully thin. The test procedure has a lot to do with the flow numbers. Especially on the exhaust side.

Max-effort deal around here is usually between 303-305 without moving the pushrod.... 290 is a lot easier.


Agree

YW .... I'd like to see a 330 CFM IV. I know Pete had talked about the potential being there. Unless you fill the water jacket behind the ports in not sure how one would get there.

I think the main thing holding the early efforts back on the V builds was lack of intake manifold knowledge. More times than not the factory dual plane was the winner.

Hi Stan, happy to share. I'm glad there is interest. I've worked on a couple pairs of heads done by Mullins. One pair were SD-455 that flow 280 @700. The other pair were a bit disappointing. They were HO heads that retained the 30° seat and went mid 250's. Very consistant from port to port and used large corner radius on the intake ports. However, I don't know the intended application and maybe they flowed enough air to accomplish the task at hand.

Like this ;)

Thanks Paul. Never saw an Mullins Pontiac head in person only in magazine articles. I had a few friends running 426 Hemis and did get the see his work on those.

What valve sizes are in those RAv heads?

This what i have for numbers on RAV heads

Pontiac Ram Air V 44 Iron
Exhaust = No Pipe
Bore Size = 4.18
2.19
0.20000 - 151
0.30000 - 164
0.40000 - 196
0.50000 - 252
0.60000 - 272
0.70000 - 286
0.80000 - 296
1.77
0.20000 - 86
0.30000 - 117
0.40000 - 145
0.50000 - 164
0.60000 - 176
0.70000 - 185
0.80000 - 190

Pontiac Ram Air V Ported Arrowhead Automotive SF600 Iron
Exhaust = No Pipe
Bore Size = 4.18
274.0 / 0.0 cc's
2.19
0.10000 - 73
0.20000 - 150
0.30000 - 222
0.40000 - 279
0.50000 - 324
0.60000 - 356
0.70000 - 372
0.80000 - 384
1.73
0.10000 - 57
0.20000 - 109
0.30000 - 152
0.40000 - 186
0.50000 - 210
0.60000 - 229
0.70000 - 234
0.80000 - 239

Stan

Juan reduced the port Vol 10% and kicked the flo to 370.As Paul posted looked like a layed over D port.Tom

Interesting numbers Stan thanks for posting.

I did some factory V stuff years ago. I remember both pair flowing around 370 at .700. One pair had the exhaust ports chopped of the side of the heads... Those moved a lot of air!

Mullins was definetly one of the top guys back in the day. It's fun seeing these vintage heads and what the the guys were doing. It's a lot easier today.

The V heads have 2.20 valves. Race port RAIV used a 2.125 with a 45° seat at the others a 2.11 with a 30° seat.