69 N.O.X. RATT

Ya, I know, I hate to admit I have a few friends that drive Mopars.

Motor 4.5 X 4.125 Slowpar Mega block
Ported Indy heads
Indy intake
1050 Dominator
10.5 to 1
Solid roller .660, 264 at .050 on a 108 installed on a 104 ICL

Muscle motors built this motor and looking at the dyno sheets the interesting thing I noticed is the more timing they took out of the motor, the more power it made. Max power was at 30 degrees of total advance (race gas). They tried 28 degrees and from 4000 to 6800 it only lost an average of 2 hp.

Best pull:

Tq / Hp
4000: 644 490
4100: 661 516
4200: 675 540
4300: 684 560
4400: 693 581
4500: 699* 612
4600: 699 612
4700: 699 625
4800: 697 637
4900: 695 649
5000: 692 659
5100: 689 669
5200: 687 680
5300: 683 689
5400: 678 698
5500: 674 706
5600: 668 706
5700: 668 712
5800: 650 718
5900: 639 717
6000: 629 718
6100: 620 720
6200: 613 724*
6300: 603 723
6400: 592 722
6500: 581 719
6600: 572 719
6700: 563 718
6800: 552 715

Looks to me like a pretty efficient cylinder head with a good exhaust port. The motor really hangs in there and continues to make good power high in the rpm range. Muscle motors shut it down at 6800.

This is going in a 70 4 spd Challenger.

Any opinions, other than he should get a BBC :lol:

427Hotrod

Very impressive! The curve looks very similar to the first version of my 540 except it hangs on much better at the top end.

The Indy heads are amazing and it's hard to imagine the power they produce with an inline type valve head. Those suckers can move some air! Just goes to show you there are lots of ways to get the same results and "obsolete" designs are often easily compensated for with some real engineering, which Indy has done. Looks like they have the chamber design down to be a very fast burn type.

Were the heads out of the box or was work done to them?

Looks like you're going to have to make sure you have some serious power with your new 540-572-632 to make sure you can spank him!

JIM

SWCDuke

I'm assuming those numbers are on a lab dyno with open exhaust.

A street legal exhaust system is going to generate significant backpressure, and when conbined with all the duration and overlap the output is going to suffer substantially. Also, idle quality will be very poor as will part throttle performance.

I wouldn't want to pay the fuel bill.

The modest amount of spark advance necesssary for peak power indicates that the combustion chamber is very efficient. What are the BSFC numbers?

Duke

69 N.O.X. RATT

Jim,

The heads are ported, by Muscle motors I believe. I was impressed by the power and rpm range also. Althought the cam has some duration, the lift is relitively modest. As for my new motor needing to be pretty stout this is the same friend building the 572 Hemi, should be posting some dyno numbers on it in April or May. The Hemi should make some big numbers, 12.5 to 1, Stage 5 heads, etc. Going into a 68-69 Road runner This 528 was a 660 Hp 493 untill it dropped a valve, since the block was cracked he built the 528.

You really got me thinking on the tall deck idea, I might go as big as 598. There is a company in NV that sells complete 598 short blocks for 4,000.00 That plus a little nitrous would really test that Tom's rear end. I am going to drive down to Jeffco trannys next week and look at thier 4 spds. I want to take some measurments and see how much cutting it will take to get it to fit in a Vette, they are the same size as a Lenco so it will need some messaging.

Duke,

This car is a 1 to 2 day a week street pounder, we all drive to the local car shows (donut shop in H.B, etc) sit around and bench race. Every now and then we go to the track, break something, make excusses why we can't get a better 60' than 1.8 in Carlsbad and go home until next time.

The BSFC numbers are as follows:

4000 .388
4100 .402
4200 .394
4300 .389
4400 .388
4500 .388
4600 .39
4700 .392
4800 .4
4900 .404
5000 .409
5100 .413
5200 .416
5300 .42
5400 .425
5500 .433
5600 .439
5700 .447
5800 .457
5900 .463
6000 .469
6100 .474
6200 .475
6300 .474
6400 .473
6500 .472
6600 .475
6700 .476
6800 .479

I have a rough idea why BSCF is important, do you mind a explanation why ?

The Green Rocket

Yee Haw, that will be one dandy street engine!

Duke, what makes you think that much of an exhaust system will be installed on the car? I'd be suprised if much more than a short muffler and dumps are used. Fuel bill? - your'e killing me! (and missing the point of a big inch engine - torque baby, on demand, any ol' time) Big inch engines easily take camshaft profiles that make lesser displacement stutter at idle. My 496 idles smoothly @ 800 rpm, that 528 is a bigger engine with a more aggressive cam profile - but I bet it will idle nicely @ ~ 1,000 rpm.

Thomas

SWCDuke

Brake specific fuel consumption is a measure of thermal efficiency. Typical engines run about 0.5 at the torque peak with a 12.5:1 A/F ratio. That means one-half pound of fuel is required to generate one HP for one hour. The lower the number the higher the thermal efficiency, which means more power for less fuel.

Typical best (lowest) WOT BSFCs are at around the torque peak or somewhat below, and 0.4 is impressive. As you go beyond the torque peak, the combination of lower volumentric efficiency and high internal engine friction increases BSFC and 0.6 at the power peak any beyond is not uncommon on highly tuned high revving engines.

BTW, the mean piston speed at peak power is 4263 ft/min, which is also very impressive for a pushrod engine, especially one with inline valves. The practical limit on mean piston speed is about 5000 ft/min, which is what F1 engines are running at about 18K revs.

Duke




[Modified by SWCDuke, 9:20 AM 12/28/2003]

69 N.O.X. RATT

Thanks Duke, great explanation.