Too much intake

[Grn92LX]

Again, RPM ratings mean squat! That ALL changes with bigger cubes, cam timing, spacers. I've seen a dyno graph of a 347 with a mild buddy rawls custom solid roller cam on a TW headed 347 with a trickflow R manifold and it DIED after 5500 and made lots of low end torque because thats what the guy wanted.

Just an FYI, you have 10 second capibility with the heads your working with (assuming their legit) Figure out exactly how fast you wanna go. The cam IS the key to this puzzle. I'm building something very to your plans and i'm looking for low 11/high 10 second power. My vote is the R or the victor manifold but the holley and rpm II will work fine too. Like I said, I prefer to take it a step above the norm, I wanna go fast and win races I'm also working with smaller unported TW heads so I NEED the bigger manifolds. I don't care about over excessive low end torque, i'm building an 11:1 347 it'll make PLENTY of low end grunt for me. Everyones got their own opinions, this is mine.

 

[Michael Yount]

"I want to LEARN this stuff, not run to the nearest 'pro' and ask him to do it for me"

You'll LEARN a lot more working with the likes of Buddy or Ed than you will from most of the 'stuff' that passes for advice in most of the threads. The process of gathering actual data about your components for them to model the set up will be a BIG learning experience. Most importantly, you'll have some certainty that the combo you're putting together is gonna perform like you want it to. Don't confuse actually DESIGNING the combo you want with GUESSING at it.

But - having said that - best of luck; sounds like you're having fun trying to figure it out and that's half the battle. I hope it works out like you want it to.

 

[tmoss]

So you want to learn grashoppa? Here is a good site that has some calculations that will help you in some respects. It's a motorcycle site but the calcs allow the use of V8 data input:

http://www.rbracing-rsr.com/calculations.htm

Here is a place to download your own dynamic compression calculator:

http://cochise.uia.net/pkelley2/dcrvb6.zip

 

[Michael Yount]

....and here's one that will help you understand why trying to select a cam based on things like lift and duration, or, heaven forbid, a popularity contest in the forums, is tantamount to guessing. http://www.wighat.com/fcr3/

 

[tmoss]

I'll ante again too - here is one to help you understand valve train geometry:

www.mid-lift.com

You won't find hardly any sites or articles on manifold design, but if you do a search on "MIT" you should find Neil Erickson's porting website where you'll find and article on "Port Limiting Velocity"

 

[tmoss]

There is also a nice excel spreadsheet on my porting webiste under downloads that will help with some sim0ple calculations on engines and cams - see the link in my signature. There are also guides there to porting and manifold installation.

 

[detroitmuscle99]

Again, RPM ratings mean squat! That ALL changes with bigger cubes, cam timing, spacers. I've seen a dyno graph of a 347 with a mild buddy rawls custom solid roller cam on a TW headed 347 with a trickflow R manifold and it DIED after 5500 and made lots of low end torque because thats what the guy wanted.
QUOTE]


well, no, rpm ratings do mean EVERYTHING, because when you look at those rpm ratings it tell you what parts they want you to compliment that cam with example:
comp xe274hr (for compuer compatible 5.0 based engines)
hydraulic roller- 2500 stall (or stick) 3:55 or higher gears, better heads, intake and fuel system.
operating range- 2200-6200

if you selected a manifold with a matching RPM range like:
edelbrock Performer RPM II (part #7123)
operating range- 1500 - 7000 (making considerable power gains from 1500-6500)

say the same motor had a set of Edelbrock RPM heads (1500-6500) and 10.5:1 compression, it would make awesome torque and hold it from 2000-6500 rpm, and make peak power somewhere near 6200, it wouldn't matter if it was a 347 or a 302, the powerband would be within 100 rpm of each other, yes, its bigger, but isnt a super high compression (13.5:1 comp.) 408 windsor, if you wanna race car- then build a build a big inch race motor, then you can take advantage of the torque a real big motor affords you. But if you're building a streetable (less than 12:1 compression) 347 you arent going to be getting into anything wild enough to even consider some of the minute differences race stuff incorporates. Once again, just build a well matched combination, it'll generate solid power and you'll be happy in the end.

 

[shootme5150]

Thanks for the links and info, guys. I'm trying to finish my sub enclosure right now, but I'll be tearing through that info to make an EDUCATED decision sometime this week Again, thanks for the help.