I have pretty much settled on this combo for my Vette project. The goal is 1000 hp naturally aspirated and then a bunch more with nitrous. Looking for educated, or uneducated opinions

BBC
555 or 572. Still trying to figure out if I can make the 4.375 stroke work in a 9.8 deck. I am a little restricted because of the ring pack neccasary with the nitrous pistons. None the less it will be a 4.560 bore and either a 4.25 or 4.375 stroke.

CNC AFR 357's with a little extra work done to them. Comp stainless rocker arms
Solid roller, 289 and 296 at .050 .750 lift. on a 114 LSA (nitrous)
Hogan's fabbed tunnel ram with 2 Pro-systems 1050 nitrous Dominators
13.5 to 1 compression
Aluminum rods
Wet sump

I am going to have Jeff Prock at Applied Nitrous Technology plumb two Pro race Foggers in the Hogan's. I plan on spraying a total of 550-600 hp worth of nitrous.

This motor is about 1/3 of the way done. It will be about a year before it is done. When I finish and get it on the dyno I will post the results.

 

I think you could make as much or more power for less money if you dropped the N/A idea and went with a blower...you could still add nitrous if you wanted.

I'm making around 675 HP on a blown 383 with what I'd consider a "mild" tune for the dragstrip. With a bigger cam and more boost I figure I can reach around 800 HP...just think what you could do with an engine the size your talking about.

Deen

 

Hi John,

I think you'll be close, but making 1000HP on "just" 555 to 572 inches w/ conventional heads is not trivial. But w/ the Hogan sheet metal tunnel ram and a great set of headers, you should be close. Use Westech's soft dyno and you might make 1100!

I thought you were looking at Pro Topline or the new Edelbrock Victor heads? Nothing wrong w/ the AFR's -- you know I like them!

Take care,

Mark

 

I am going to use the new Edelbrocks but since they are not out yet I said AFR. Everybody knows how good the AFR's are and these new Edelbrocks beat them by 17 hp on a Musi 565. I said AFR just for sake of easy comparrison.

I heard Westech recalibrated their dyno

Dean, I looked into the blower idea, what kind of blower are you running?

 

I'm running a BDS large bore 671, currently pushing 14 lbs. boost at 7% overdrive. On a 383-400 c.i. that blower is capable of pumping up to 26 lbs. boost. At my current settings I'm less than a tenth of a second away from dropping into the nines in the Qtr. Time to change my roll-bar to a full cage. What's nice about a blower is you do not need to turn extreme RPM's, run high spring pressures, or put up with a "radical" engine. Mine idles (lopes) at 900 RPM, runs a milder roller (252 int./260 exh. @ .050") and maintains around 180 degree water temp. Of course when you hit the loud-pedal it's a whole nother story.

Anyway good luck to you no matter which way you choose

Deen

 

I have a 14:1 565ci (4.250 x 4.6) with untouched AFR 357s, single plane Dart Intake, 1250cfm Dominator, jesel sportsmans with a 286/296 .748/.748 112LSA 4/7 swap cam.. I never did dyno it before we put it in my 72 Nova but the trap speeds and weight show it making in the 850-900hp range. The car only has 30 runs on it so we still have lots of tweaking left to do.

I think you will be close to your 1000hp target with what you are planning.

 

Thanks for the info Deen.

Matt, Killer ride, what does it weigh and what have you run, et.....mph?
Untouched AFR's meaning non ported, no CNC?

 

My gut tells me it's going to be pretty tough....I'm thinkiing you'll get all over 925-950 maybe....but I'm not sure even the CNC 357's will support the rpm needed on a motor that big to make 1000 hp. I may be surprised....but it's going to take some serious airflow. The Hogan and dual carbs will really help, so the heads better be ready for it.

I think the N20 will carry it a long way past of course, but I think when you really get to spraying it , a little more port volume will help.

Are there going to be any new Edelbrock larger volume heads too?

If you're going race gas, might as well put 15.0-16.0 in it huh?

I have a buddy with a 572. 14.0 compression or so, it had lightly ported Brodix -2's on it and it made around 860-880hp. It actually amazed me how well it did with heads that small. He recently went with some older Big Chiefs and he was at 980 or so. Almost 1000 hp. He has changed cam and is about to re-dyno it soon, so we'll know how it does. His old cam was designd for regular heads, so he has upgraded to something that will support the big heads.

He's running 7.70's@183 in a doorslammer Monte Carlo (tube chassis) at Denver's altitude with a 150 shot.

I still think if I was going through all of this, it would have Big Chiefs or Dukes on it. Check out folks who are stepping up to the latest greatest stuff. My buddy paid 5K for his setup. It included pistons, heads with titanium valves, cam and intake along with full Jesel rocker setup.

Either way, sounds like lots of fun!


JIM

 

on a loose dyno yes in reality i am thinking 900-950hp tops

 

Jim, I have agonized over the Chief stuff. If this was a 632 it would have the Chief stuff for sure. After I get all caught up in the way it "should" be done, I step back and realize this going to be a back half 2700 lb car with at least 1400 hp. It will take me a while to figure out how to use an get all that power down the track. That power to weight ratio should put the car in the 7's. I hope that will be enough of a challenge for quite some time.

The new heads have a port volume of around 360-370 cc's. They appear to be pretty promising. They should be out in January.

I think 950 hp is a realistic goal, maybe the new heads will push that a little higher, we will see.

I pulled my 454 apart and found some pretty ugly bearings. I am pretty sure it was detonating (sent you an email with pics) This has me a little unsure about the compression ratio I am going to run (572). I would not mind pressing the compression and trying to limp it around on the street, but with aluminum rods I believe you are limited to how many times you can pull the caps off. I "may" back it off to 11 to 1. I was thinking 13.5 due to the fact I thought that lead based octane boost would allow me to limp around on the street at low rpms and then run good racing fuel for the track. More research needed.

 

I replied on another board too. The engine shop by me ( Ultra Tech Racing Engines) just dynoed a 580 with 12.5-1, out of the box Dart pro-1's ( i don't know the size) and a 800 lift solid roller, single dominator. They teasted several carbs and intake spacers. It made 990 with the best carb and 975 with the worst carb. All tests were with collector mufflers. This is his spare engine that he's selling. I can get you his # if you want to talk to him and get more details. They also dynoed and built a 622 with a single carb and pro filer heads that made 1050 on the dyno. I know nothing about that motor.

Mike

 

Those AFR357 CNC port heads on a 13.5:1 555CID will make 1000HP at 7000RPM with the Dominators on a tunnel ram, and have a great powerband that extends to 8000RPM. Your exhaust lobe is huge for those heads and natural aspiration, so I don't really know how your powerband will turn out with the cam you specified. You should still get near 1000HP at 7000RPM though.

 

Headerdesign.com: I am not locked into the cam. It is just one I picked from a few different engine builds, what would you suggest? Remember this is going to be a nitrous motor.

 

I'm not sure about the cam needed for 600HP added by nitrous. My focus is on race engine design for natural aspiration. Some bracket racers will add a nitrous shot in the event they mess up the launch, but my basic design doesn't need to consider the small nitrous injection to work correctly.

Just keep in mind that the low and mid-lift flow of those AFR357 heads makes the cam lobes seem bigger and more radical to the engine than with other heads of similar cc. Look at the 0.3" exhaust port flow of those heads, and compare to older designs. If you are guessing at the exhaust lobe centerline angle, you might guess 117deg.

Intake lobe might be mid 0.7's lift and mid to upper 190deg duration at 0.200" lobe lift. It looks like you know not to put a big intake lobe on low intake lobe centerline angle. This would make the big engine come on too abruptly and uncontrollably in the lower midrange, then slap you in the face with poor powerband width.