P51 guys

supervel45 wrote:I have heard that some of the Pro's say 2 heads can flow the same numbers on the flow bench, but on the Dyno, on the same shortblock, one will out perform the other, as far as peak HP numbers, due to port velocity. Aplication and actual HP numbers, would seem to be a consideration also, when chosing. The definition of better is relative.

richter69 wrote:Flow bench nationals...

hey Tony are these heads like your old Doves? The ones that had the intake ports totally removed and secrions of pipe jamed in there?

supervel45 wrote:I think it may have been Sonny Lennard, and maybe few other bigdog's that mentioned the point, about the flow numbers. Peak HP dyno numbers are not always foolproof either, but in a full out race motor are a nice guage.

supervel45 wrote:Yes Sir. And it's all about the Combination, of the total package, sitting behind the green light when it drops.

whitefield wrote:

supervel45 wrote:Yes Sir. And it's all about the Combination, of the total package, sitting behind the green light when it drops.

So then flow bench numbers and dyno numbers are just tuning tools  !

 Compression , headers and intake would change the flow numbers too ?

yellowhorse7 wrote:

whitefield wrote:

supervel45 wrote:Yes Sir. And it's all about the Combination, of the total package, sitting behind the green light when it drops.

So then flow bench numbers and dyno numbers are just tuning tools  !

 Compression , headers and intake would change the flow numbers too ?

Weeny swinging tools  

supervel45 wrote:That is not what I am saying. Other varable's play a part in a cylinder head choice, like you mentioned on bore and stroke. I meant that dyno number's are "actual verifiable numbers" on one sample engine, with the "actual heads" that you are useing.  The E/T is the final goal, with the whole combination (Vechicle engine, trans chasis, ect. . It's seem's like the torque/horsepower debate, which one wins races, is what this is coming to. That was not my intention.

LivermoreDave wrote:I listened to Richard Maskin's answer to an air flow question, he replied " air flow should be your least concern, it's simply the result of a well designed port". David Reher sitting next to Maskin nodding his head with approval!

Just sayin,
Dave.

IDT-572 wrote:

yellowhorse7 wrote:Sad to see that all everyone got out of this is a perception that P51's are weak. No one ever said that. In fact, the whole point of the discussion was ignored and really never answered. EXACTLY HOW MUCH BETTER, AND WHERE, ARE THEY BETTER THAN SCJ's. Blake and John are examples of people making them work. Yes they will pick up but not enough to substantiate an "upgrade".

My opinion is from my hands on experience is, out of the box there is a huge difference in performance between the two heads. For someone wanting to just change heads on a 750 hp SCJ with no other mods to his engine, this would be a very worth while up grade.

Now, looking at fully ported casting to fully ported castings stepping up a valve size in both castings, there is going to be around a 50 to a 70 hp increase going to the P-51.s.

Keep in mind you may have a rule deal holding you to the SCJ casting. You can sell the SCJ's and recover most of the cost of the P-51's. It is a personal choice how much you want to spend to pick up 50-70 hp.

I have seen several 900-950 hp P-51 builds that are easy to duplicate. and also several easy to build 1000-1050 hp A head builds. People step up to the A head engines for 100 hp increase all the time and have to buy intake, pistons, headers, ect. for not much more power but a good bit more coin.

Its all a personal choice.  Also one could look at it in another aspect. They could be stepping up from a stock type head and are buying pistons and bypass the TFS Streets SCJ's and all the others and go straight to the Kasse's.

I don't understand why this is such a big deal............. it's all a progression to better heads for us. It hasn't been that long ago we didn't even have an aluminum head.

And running mid fives 50-70 hp is a little over a tenth of a second. 150 hp is worth less than 3 tenths. it takes a good bit of hp to go a little bit faster at that E.T.

Lem Evans wrote:I've heard this deal several times but, what is much over looked is that these guys have designed ports that the SCJ/P51/C460/etc castings don't have room for.  

IDT-572 wrote:It just gets to a point to where you can only get so much air through a low port entrance head. Hard to keep the air on the short turn when it enters below it and exits below it. Air is making a big turn for a long distance.

5pointslow wrote:if anyone has any P51 heads that they dont like for whatever reason i can Pm you my adress and will gladley under achieve with them ..lol

  

rmcomprandy wrote:

supervel45 wrote:I have heard that some of the Pro's say 2 heads can flow the same numbers on the flow bench, but on the Dyno, on the same shortblock, one will out perform the other, as far as peak HP numbers, due to port velocity. Aplication and actual HP numbers, would seem to be a consideration also, when chosing. The definition of better is relative.

THAT is definitely true ... it is a very dangerous thing to try and race air flow numbers as it only tells about PART of the total package.

fordmanmatt wrote:Me too

  

5pointslow wrote:if anyone has any P51 heads that they dont like for whatever reason i can Pm you my adress and will gladley under achieve with them ..lol