The Green Rocket

Its not going in my Corvette, but I thought a few of you might enjoy this.

The 468 in the '65 ElCamino I recently bought went pooka pooka after 4 passes at the drags (tore the main bearings out) so I decided to upgrade to a 496 while rebuilding.

Today was break in and tune up time on the engine dyno, here are the results:

RPM C_TQ C_HP
2500 496 236
2600 497 246
2700 498 256
2800 504 268
2900 515 285
3000 531 303
3100 544 321
3200 557 339
3300 567 356
3400 573 371
3500 575 383
3600 573 393
3700 565 398
3800 556 402
3900 545 405
4000 540 411
4100 544 425
4200 555 444
4300 570 466
4400 581 487
4500 591 506
4600 596 522
4700 600 537
4800 602 550
4900 594 555
5000 589 561
5100 586 569
5200 584 579
5300 583 588
5400 581 597
5500 579 606
5600 573 611
5700 574 622
5800 571 630
5900 565 635
6000 558 637
6100 550 638
6200 542 640
6300 533 639
6400 522 636
6500 511 633

Here are some engine details:
496 cube, 4.31" x 4.25, ~ 10.7:1 compression ratio (8.13 dynamic compression ratio), Brodix BB-2 heads 2.25" x 1.88" valves ports reshaped to flow in the 380's intake and in the 280's exhaust, solid roller cam: .653/.660 lift (.637/.642 lift after valve lash) 248/254 duaration at .050 110 LSA installed at 108 degrees, Victor Jr 454R intake port matched to heads, profiled 2" spacer 4500 to 4150 carb adapater, Holley 1050 Dominator with stub stack, 6 valve mechanical fuel pump, Mallory HEI distributor.

With the tired 468, which showed 368 rwhp a couple of days before the drags, it ran a 12.02 at 111.85 - I'm looking to improve upon that :)

Now I need to select a torque converter - and with a torque curve like this I'm not sure that it will need much stall to fly, besides I intend to hit the streets on a regular basis. Currently the race weight with me in it is ~ 3,720 lbs, turbo 400, 4.11 gears. With this torque curve I think the 4.11's and 4,500 stall converter that I have are overkill, I have a 3.73 differential that I may try out. I don't think I would do it right away, but if I put the car on a diet a Powerglide would probably make it quicker.

Thomas

427Hotrod

Now THERE"S a killer street motor!! That thing has blower motor TQ curve....flat and never dies!

What size tires do you have? I'm betting one of the 10" 2500 converters (that actually flash to 4500 or so with a motor like yours) and a set of 3.73's or 3.90's would be killer. Ought to put you through at a decent rpm with some 28-29" tires. Can you fit some 30's under it? May be able to stay with 4.11's.


Great looking motor....congratualtions!

JIM

The Green Rocket

Jim, yeah the torque "curve" is interesting that way, I understand that is a common characteristic of a 4.25" stroke big block setup mild like this one.

Currently the tires are E.T. Streets 28 x 11.50 x 15. There is not much wheelwell space leftover on the '65 for anything larger. Once the 28's stretch under acceleration it fills the remaining wheelwell space. Of course a set of tubs would solve that. I'll run it with the 4.11's first, but I'm sure to install 3.73's soon after.

If all goes well I should post drag results in a couple of weeks.

Thomas

632C2

Great combination! :cheers:

Now, what about that nitrous?!!

Steve

The Green Rocket

Steve - launching this thing will be pretty fun the way it is, but a "little" N2O on the top would be interesting :)

Thomas

69 N.O.X. RATT

So when am I going to see it out at Garden Grove?

The Green Rocket

John, it was at Garden Grove Main St Cruise once about two months ago, I'm expecting it to be on the road in the next couple of weeks.

Evening Orchid in color, black primer VFN 6" cowl lift off hood.

Thomas

OatBoy

congrats, street motors dont get much better than that.

Chuck Harmon

Green Rocket,

Your numbers are very encouraging! You've got better heads and intake, I've got more compression; but your cam is very close to the specs of the Crane solid roller I am now installing. I think I will like the results, yours are terrific! I peaked at 483rwhp before, looks like I can expect a bit more on top, but MUCH more down low.

Chuck

marky mark

WOW :eek:

I'm asking some qustions on various BB combo's on another thread and thought I'd see what you thought of taking the 496 and putting a factory low rise intake with either oval port or rect port heads (not as nice as yours) and maybe a bit smaller solid roller cam. Would the TQ / HP #'s drop off dramatically?

Regards, Mark

Chuck Harmon

Marky mark,

The 496 is a very big engine, but mainly due to its long stroke. A longer stroke does not make more horse power, but it does make much more torque. Green Rockets engine is very nice in that it still makes power even to 6500rpm. Yet my 427 with factory unported aluminum heads would still make 560+ gross horsepower on an engine dyno. I expect to gain about 40 horsepower with the new Cran solid roller. If I were to change to a modern single plane intake manifold and similar heads I have little doubt that I would make at least as much power. If I even had my current heads CNC'd (porting done by a computerized milling machine) I would be close.

The question you need to answer is how much torque do you really want? WA 2 Fast has a low compression 454 with mild roller cam, new high flow heads and intake manifold. Look up his recent post for an idea of what you would have in store. It really sounds perfect. The LS6 manifold would probably cost you about 30-40 horsepower compared to a new design, but it is only about 15 hp less than my L88 high rise. I think WA 2 Fast even has an extra LS6 manifold lying around.

I believe that if you followed a less expensive route and just stayed with your 427, using similar parts to WA 2 Fast, you would be thrilled with the performance without losing any of your current engine's smoothness.

My 427 really makes the power upstairs, but it still melts the tires in the lower gears. Don't think that wider tires will cure this. My ZO6 has wider and stickier tires than 99.5% of of all C3's and it easily melts them with only 350rwhp. I can't stress enough that copying someone else's engine that you really like is probably the best way to go. It is so easy to get caught up in horse power wars with the end result less desirable and much more expensive than building one a few notches lower.

Chuck

marky mark

Thanks Chuck,

As usual, you give good advice. I will look up WA 2 Fast's motor specs for comparison.

Can I assume you are running rectangular port heads on your 427? What brand of head? What carb?

Also, thanks for coming up with a figure on how much less hp the LS-6 manifold would produce. Do you think the torque #'s would fall by a similar margin too???

Thanks again.

Mark :flag :chevy

Chuck Harmon

Mark,

My heads are part #14011076. They are the D port aluminum heads that are the direct replacement for the 2nd design L88 open chamber head. I am running the Holley 950 dp from Holley pro shop. Basically a smoothed 850 with the choke tower removed. Wes (WA 2 Fast) is using the same carb.

The biggest difference you will have with the LS6 manifold is if you use the stock hood vs. the functional fresh air hood. You will get a 1% hp increase for every 7.5 degrees farenheit you drop the incoming air temp. It does get hot under there! If you keep the compression at about 10 or less, I don't think you will have a detonation problem without the cold air hood. The LS6 manifold was a pretty darn good one. At around 500 horse power, I doubt that any but the most sensitive butts could tell the difference behind the wheel. The fresh air is good and will make more difference, but I really love the look of the stock hood. In addition to myself, Wes, Steve Straus, and others have felt the same way, yet ended up going to the L88 hood once the full effect of the power addiction BIT HARD.

Another engine to check out would be Les69. He has a gorgeous 69 with new flat tappet cam that also makes very good numbers and drives very well. Definately one that will also humble my ZO6 in a straight line, at least up to about 110mph :yesnod:

Chuck

VetteLS6

woooooooohooooo should be a train if you can make it hook! :cheers: :cheers: