Hey guys, ive been looking into building a motor for a while and my goal is 700 N/A hp. I want the motor to be solid, so I might have to tone things down a bit.??? Also I cant go higher than 10.5:1 CR because I can only get 91 octane out here in cali. Here's the base components im looking at.

-Warhawk tall block 4.125" bore 10.5 CR
-Lunati Pro Series 4.125" stroke crank
-Manley Lightweight I beam rods
-Futral motorsports cam 239/246 - 114+4 .612/632 (specs could easily be changed)
-High flow heads (something that will flow in the 350-360cfm range)
-Fast intake with 90mm throttle body

Guys keep in mind that I want this motor to be solid (last a decent amount of time before rebuilding) and run on pump (91 octane) gas.

 

For that big of a block forget the Fast 90/90 and go with a sheet metal or a ported ls7 intake. It can't even support enough air for the 402 buildups. I would say **** an off the shelf cam and get something tailored specifically to your heads and peripherals that you do so choose. The ETP 255's or perhaps the World LS7X heads would be nicely suited to that application. And if you're going to go with a 4.125" stroke, why not get a 4.25" stroke? It's the same price for the lunati.

Don't get caught up in Static compression ratio numbers. I can make a 10.5:1 SCR motor detonate like hell with a small cam where a 11.5:1 with a big cam might not even flinch. Dynamic compression ratio is where it's at. Talk to a motor builder and see what's right for your application and let them do the design process. After all they do this a hell of a lot more than you do.

Nate

 

what's the target rpm?

 

Yes, i'm shooting for the same thing with a smaller 434, but with a sb2.2 intake and 1550cfm throttle body, solid roller with big lift, 11.7 to 1 compression, and 7500rpm.

 

To hit that, you will need a lot more solid roller cam, better flowing heads, a lot of compression, less stroke, custom intake, dry sump, about 30-50k and no it will not run on 91.

People get caught up in hp numbers. Build a simple 550/550-575/575 motor that you can turn the key and enjoy. It will be just as fast on the street. When I was N/A, I could spin my 100 wear rating 12" tires at 90 mph..

Talk to Rick at Synergy. http://synergymotorsports.net/
510.796.3749 He only builds his motors in house (no internet turn/burn); he takes about 10-15 hours more on each one and has at least a half dozen stroker builds going on now (this is very important).

Edit. I am talking rwhp on the above, with a hydralic cam.

 

well i hope you can get here with 441cubic inch. American Speed can get you 720 bhp on a 406!

Chris.

 

Comp cams almost got there (675hp) with an efi, 410", 10.5 to 1, sb2 headed motor with a 230/236 590ish lift solid roller, at 6800rpm. It is not as hard as some would have you believe. Your heads and intake setup will be your biggest deciding factor. Good luck.

http://www.compcams.com/community/pr...69camaro-1997/

 

I assume you are wanting 700 hp at the flywheel? bhp not rwhp?

 

yes that can be done Naturally aspirated.

It will be tough on pump gas but definately achievable

 

Don't take this the wrong way but that seems to be a very mismatched combo. You got a HUGE MOTOR with a tiny cam and BIG HEADS and small intake. Here's my .02 setup...

-Warhawk tall block 4.125" bore 10.5 CR
-Lunati Pro Series 4.125" stroke crank
-Manley Lightweight I beam rods
-ET Splayed valve heads 265cc
-Jesel J2k Rockers
- Solid valvetrain
-2" headers
-260-280 duration cam .650-.750 lift ~110 LSA
-Sheet Metal intake 105+mm TB
- 13.0:1+ CR
Phil

 

its definately achievable, but u ned a bigger cam and a custom fabricated sheetmetal intake,to get that on pump gas will be a lil harder, but anything can be achieved for the money!!!!!

 

Unless something has changed, the ET splayed heads are 285cc's and not for street use. The 265's like I have however are "offset" and very useable on the street. With that cam size and intake, he better be happy with 8k rpm's. His goals are atainable with a high compression, solid cammed, FAST 90 setup. Hypothetcally speaking, were looking at 595 rwhp to obtain 700fwhp. I agree that the set-up may not be optimum, but it all depends on the options that fit your needs. For 90% of people, sheet metal intakes won't cut it on the street. The FAST 90, unfortuantlly, is the best thing we have to work with for under $1500. He's already ruled out high compression, so I'm gunna say, build you combo around your needs, and be happy with anything over 500 rwhp. I would personally use:

-Warhawk tall block 4.125"(more if possible) bore 11.5 CR
-Lunati Pro Series 4.185" stroke crank (448 ci at no more cost, plus added TQ from the stroke.)
-SCAT H- beam rods
-ET heads 265cc
-Jesel Mohawk "lightened series" Rockers (Only ones avalible for 265's)
-Big hydraulic cam (250+ durations) and keep DCR at a 91 octane user level.
-Kooks 1 7/8" stepped to 2" headers
-FAST 90/90

I say this because of the "reliability" you asked for in the begining. You should be able to knock down 550+ rwhp with the above combo, putting you just shy of 700fwhp with a killer, street friendly combo.

 

I think this combo might make a little more than 550 rwhp, there are 408s doing this with less head, and we are working with 40 more cubes... my guess 575-600 rwhp, unless the intake really holds back the motor. I did notice you put the plus on there Now if someone were to get crazy and got a sheetmetal or the 8 TB harrop intake and make that work, we could go plus another 50-70 hp from what they have told me..... this is assuming with a 6 speed of course. Damn I need to start building a new motor.

 

I always like to keep my guesstimations on the low side, so I stick with the low+ thing. As for the 8 TB intake, not everyone is as crazy as me. Many don't want to spend that kind of money on a intake, but soon they will realize they are a huge restriction to the potential of the heads we have avalible to us.

 

What about running less compression, 9:1 or 9:5.1 with more timing? I got the 91 octane problem myself.

 

I don't think you will need the 13:1 compression, or a cam over 260. However, the Fast 90 could be challenged. Single plane carb style, sheet metal, ITB, something on the intake to flow more air.

The ET 265 sounds about right. And it is definitely a solid roller cam.

 

With some nasty cylinder heads and enough cubes, it could easily be done. 700 fwhp isnt that tough (its only money right). 700 wheel and you might be getting a little tough.... you would need some SICK heads, 450 cubes, solid roller, and a carb style intake to take you up to 8k rpm. And you are asking alot to do it on 91 octane.

There are also a ton of little tricks that could make it easier....

 

I don't wanna steal the thread from adam but, it seems like a few guys chimmed in here. I am looking for "600 bhp" with a 402/408. Anyone have any recommendations for compression, cam, heads, intake. I am looking to run 91 octane as well. This will be in a truck with a 3000 stall, and must be streetable enough for a daily driver. Thanks

 

I don't understand we you all are telling him to go with the sheetmetal intake and crazy aftermarket heads when (two threads up) a stock LS7 with lightly ported exhaust ports, cam and bolt ons is at 620rwhp. Even if they tone it down to say 600rwhp and make it drive a little better, this is being achieved with a relitively untouched motor with 11.1:1 compression (91 octane safe) and it comes out to be around 700bhp. buy a stock LS7, and rework it until its to your desired hp level, which obvouisly won't take much at all. why is it harder than that?

 

its not that hard to make power, and it dosnt take a **** load of money. it dose take money but not like 30 grand. my 2nd cousin has a 427 sbc and it is n/a. its carborated with mildly poprted afr heads and a pretty grumpy bumpstick. i think .612 lift at 260 @ .050 or somthing like that. it made 600 or so hp on pump gas. and here you guys are with your all aluminum cnc ported efi **** only making mid 600's? wtf