P-51 heads

Dave De wrote:

Gary Blair wrote:

Lem Evans wrote:
"580 cubes, 13.4 comp, 3100 pound car, both heads were ported and the SCJ heads have 2.25 valves"

I agree that there may be other issues but, your SCJ heads having the 2.250" intake valves have removed one of the advantages that the P51 have over the typical 2.200" scj frpp head.

Lem,
Is this SCJ one of your builds? Runs real nice.

Gary,
Thanks for the compliment. Lem helped me with my first build a 547 and had the heads done at Oaklys shop. The 547 was running 9.45 until an oiling problem got away from me. When I went 580 he wanted me to go A head and I said no. We all know Id be well into the 8s with that setup. I could almost see how quickly Lem typed " No sir, its not".  I tell you what a guy and he didnt even say I told you so.
So here I am with this Frankenstein set of parts but my limits are no power adders, no chute and no bars (I hope). So the limit is 150ish mph. And its knocking on the door right now.
Lem has been very good to me almost like a coach or a mentor. I never consulted him about P51s over SCJs. I think he would have said there is much on that change but then he did afterwards. I was going to buy another set of heads anyway for my street car and the P51s came up FS used. Better to have the P51s on the race car even if they are only worth a 10th over my SCJs.

Looks like you have a good working C-6 as well. I used to run one in a 2700 lb 67 Mustang years ago. I found no matter what combo I had in the car it liked to be short shifted so to speak at 5800-6000 1-2. It liked to get out of low as soon as you could. I like to think you would want it to drop back into the grunt zone and let it accelerate to 7200 or so. Looks like you have plenty of grunt too.

Gary Blair wrote:

Looks like you have a good working C-6 as well. I used to run one in a 2700 lb 67 Mustang years ago. I found no matter what combo I had in the car it liked to be short shifted so to speak at 5800-6000 1-2. It liked to get out of low as soon as you could. I like to think you would want it to drop back into the grunt zone and let it accelerate to 7200 or so. Looks like you have plenty of grunt too.

Launch at 3800 off the brake with 4500 stall. Notice the 1-2 time shifting at 6200. This was 1/8th mile with a 1.32 60ft. It doesn't matter that I was early .012
Skip the last 2.5 minutes. I see just under 2 seconds in first gear.

https://youtu.be/IMqaFtlSV4o

Dave De wrote:

Gary Blair wrote:

Looks like you have a good working C-6 as well. I used to run one in a 2700 lb 67 Mustang years ago. I found no matter what combo I had in the car it liked to be short shifted so to speak at 5800-6000 1-2. It liked to get out of low as soon as you could. I like to think you would want it to drop back into the grunt zone and let it accelerate to 7200 or so. Looks like you have plenty of grunt too.

Launch at 3800 off the brake with 4500 stall. Notice the 1-2 time shifting at 6200. This was 1/8th mile with a 1.32 60ft. It doesn't matter that I was early .012
Skip the last 2.5 minutes. I see just under 2 seconds in first gear.

https://youtu.be/IMqaFtlSV4o

I see, goes nice and straight. Maybe change just the convertor and leave at your 3800 and then try 5000. Is it a ladder bar or a 4 link?

Ladder

Very nice looking car you have

I've seen these movies before.

An engine that had a converter and other things that was marginal and things did not go well when the power curve changed.

Lem Evans wrote:I've seen these movies before.

An engine that had a converter and other things that was marginal and things did not go well when the power curve changed.

.

X2

Lem Evans wrote:I've seen these movies before.

An engine that had a converter and other things that was marginal and things did not go well when the power curve changed.

Okay Lem, we know the converter is crap so now Im going with a UCC 9" to stall at 5k and then the gear will be down to a 3.63
What else falls under the other things category?

I think the new convertor can pick it up. Of course it's possible that it could have picked it up with the SCJ's too. If you were to retune the P-51 with more cam I can't see any reason why it wouldn't help the SCJ's as well.

Dave De wrote:Ladder

It leaves with the right attitude. It's just right I think.

Dave,
That is one Very classic kick azz Stang, like bowling... rack em and knock em down.

Gary Blair wrote:

Dave De wrote:Ladder

It leaves with the right attitude. It's just right I think.

FalconEh wrote:Dave,
  That is one Very classic kick azz Stang, like bowling... rack em and knock em down.

Thanks for the compliments. UCCs converter should be here Friday and slid in the car Saturday for a TnT event at Milan on Sunday. I will post results for the converter and a tire test.

Update? I know we had monsoons on Saturday

bigblockfox468 wrote:Update? I know we had monsoons on Saturday

Milan was wet but the track was dry. There was a 15 to 20 mph head wind that would also go from side to side. Air was 2200 to 2500. My new converter didnt change anything and I actually was a little slower. My friends Firebird ran like clockwork at 9.06 and 151 mph same as without a headwind.
I played around with the setup and started running the 2 step at 4400. 60s were all 1.32 to 1.36
Changed the 31x14 GY slicks to my old MT 31x13 ET Drags, added one psi (9 cold) and the car pulled a 2 footer at an angle towards the wall, left in the left lane. I lifted and slammed the front end hard enough to mess up the camber and toe on the passenger side.
In spite of that it did the best 60ft for the day. I did gain one mph on the top end over the previous time out.
Im looking to replace the GoodYears with 32 talls that have more rollout and stay with 13 wide if I can find them. Probably Hoosiers or 14" MT's.
I'll straighten out the front and be back up to Ubly on the 4th.
After that a gear change.

Gary Blair wrote:

Looks like you have a good working C-6 as well. I used to run one in a 2700 lb 67 Mustang years ago. I found no matter what combo I had in the car it liked to be short shifted so to speak at 5800-6000 1-2. It liked to get out of low as soon as you could. I like to think you would want it to drop back into the grunt zone and let it accelerate to 7200 or so. Looks like you have plenty of grunt too.

^^^Did you try the short shift, could help the wheelie, and gain more through top.

It doesnt seem to matter if I shift short or high. This is because the tire height gear combination is geared to low to attain the right instantaneous wheel speed?
The UCC converter is not slipping in the 1/8th like the old converter but still I'm into 2nd just after the sixty foot when shifting at 6500.
Next step is to get some tall 32's. Followed by a 3.50 or 3.63 gear. It will be good to get this at the 150 mph trap speed again.

Now that I have more data to share on this I thought I could clear the air on my results with the change from SCJs to P51s.
The comparison from this change previously posted came from bad data. When I made the change I did not know that the trans line pressure was down and that negatively effected the P51 comparison where the SCJs had a trans with good line pressure.
This year has been an entire season chasing driveline and chassis gremlins with crashing the control arm from an aborted launch to save the car from hitting the wall. I did change a few other parts in my setup so I dont have a direct comparison but I can reasonable say that the P51s were worth .12 seconds in the quarter mile over my SCJs.

SCJs had been worked on by the Kentucky crew thru Lem with porting and 2.25 intake valves. Flowing 385?
P51s ported by Randy Malik flowed at 425, .800 lift numbers

Looking back Randy predicted the change here before he started the work on the P51s. Is he brilliant or what?
Lem made me aware that the flow number comparisons were at .800 and my cam is only at .680 so to use the full potential I need a bigger cam. I am fortunate to have Lem looking over my shoulder on this as well as Randy.

Other factors were tire change, rear shock change and converter change. These other changes factor into about .08 seconds where some testing took place prior to getting the setup straight.

Dave De wrote:Now that I have more data to share on this I thought I could clear the air on my results with the change from SCJs to P51s.
The comparison from this change previously posted came from bad data. When I made the change I did not know that the trans line pressure was down and that negatively effected the P51 comparison where the SCJs had a trans with good line pressure.
This year has been an entire season chasing driveline and chassis gremlins with crashing the control arm from an aborted launch to save the car from hitting the wall. I did change a few other parts in my setup so I dont have a direct comparison but I can reasonable say that the P51s were worth .12 seconds in the quarter mile over my SCJs.

SCJs had been worked on by the Kentucky crew thru Lem with porting and 2.25 intake valves. Flowing 385?
P51s ported by Randy Malik flowed at 425, .800 lift numbers

Looking back Randy predicted the change here before he started the work on the P51s. Is he brilliant or what?
Lem made me aware that the flow number comparisons were at .800 and my cam is only at .680 so to use the full potential I need a bigger cam. I am fortunate to have Lem looking over my shoulder on this as well as Randy.

Other factors were tire change, rear shock change and converter change. These other changes factor into about .08 seconds where some testing took place prior to getting the setup straight.

Actually a cam with near the same lobe AREA would probably be best but, getting that area with more lobe lift and less duration.