Pontiac Cat64

would 400 cfm be adequate for a 700hp 421 on pump gas. I have seen 427 builds make 750hp+ with racing fuel iv seen some heads flow north of 415cfm. I will daily this engine so a cam that will ideal with out to much trouble is a given. it also makes this hp level very hard to reach im just curious if anyones done this with an ls7

it will have custom fuel injected stacks for an intake heads will probably be lsx dr or some other extreme racing style head which will flow as much as possible to minimizes the amount of cam I will need.

will this work ? haha

Ari G

iTrader: (25)

To answer both of your threads
Save your money on the LSX DR

OEM LS7 head with a 2.250 valves can flow over 450cfm,that alone can make over 700RWHP with a good intake like stacks or equivilent

Pontiac Cat64

what valve lift is that 450cfm and are there other threads that cover high flowing ls7 heads that can flow that much, if I can get a head that flows 400+ at .650 lift that would be great. I cant run a cam set up that has .8 or 1.000 lift because it will be street driven haha idk of any cam that you could daily with that lift

it will have a nasty cam but one that will idle without stalling at round 1000rpm lol with a 2800-7500 rpm rang. ideal would be 2300-7000 but im pretty sure you cant have your cake and eat it too. ill need a lot of rpm I need to read up more about cams and rpm ranges etc but first more on heads

Orange Juice

iTrader: (3)

My stroked ls7 make 650 fwhp with cathedral heads and a cam with no more than 610 lift on pump gas. This was a pretty conservative build with everything off the shelf.

Ari G

iTrader: (25)

That is at .800 lift and ls7 have 1.8 rocker ratio

Pontiac Cat64

[QUOTE=Orange Juice;18361189]My stroked ls7 make 650 fwhp with cathedral heads and a cam with no more than 610 lift on pump gas. This was a pretty conservative build with everything off the shelf.[/QUOTE

stroked ls7 what displacement is that ? Iv limited my build to 421 because its going in an old Pontiac and the Pontiac 421 super duty was a legend, and I want to continue it even though I could bill a 470ci+ engine for the same money. also are your heads ported at all ? and what intake are you running

Blown06

iTrader: (32)

You could do a 455" ls motor. Although the 421 was pretty cool.

Blown06

iTrader: (32)

Way back when MTI was still around, they were doing a 455" package for the new gto's. I thought was pretty cool.

Orange Juice

iTrader: (3)

Displacement is 441, heads weren't touched, cam is a comp off the shelf 248, 248, 610 lift on the intake and 615 exhaust. When the motor was on the dyno they used a carb intake. They also had issues with the MSD box and couldn't spin it past 5800 rpm.

Pontiac Cat64

iv done some more Hw and this is possible, iv seen a 419ci set up make 705fwhp at 6900rpm on 98oct (Australian pump gas ) If I get a better intake and equal or better heads I should be able to make that with 93oct.

now they didn't using a dry sump with a dart block dry sump and vacuum pump so theres a lot of hp left on the table from parasitic losses, mostly windage. and with allpro lsw 2 heads that flow 460+ cfm its possible to make street able 700hp+ on 93 pump gas just an educated guess but heres the youtube link to the CID LS3 engine

that 5 octane difference should easy be compensated with a dart block vacuum pump and dry sump set up. not to mention it had 102mm intake and my intake each stack will be 50mm x8 so a lot more air and more rpms so more hp in theory.

speer13

I think it is very possible to do this when you are considering using 420+ cubic inches, judging by others results you can see you may not need as much as you have been looking at either in terms of induction etc.

After reading your other post as well I think you may be in for a rude awakening on the price.... you stated you wanted to spend around 8k in your other post but just for a basic rundown on the items you were discussing;

ITB intake system - ~4000
Mast/equivilent heads to flow 400+ ~ 3000
Dart Block/machining - ~ 3500
Rotating assembly- ~ 2500

So you may want to do some more research or talk to the guys on here who have close to those numbers because if it were me I'd rather have less power and a running engine than a bunch of exotic parts on a shelf...

Pontiac Cat64

speedmaster makes a ITB intake that's for ls7 and ls3 heads and it has 50mm throttle boddies fuel rails etc and its $1250 minus some really nice injectors that im guessing might cost 600-1000 at most ? im still reading up on injectors so input on fuel system requirements, so input would be great

allport LSW heads flow 460cfm + and they are actually a deal compared to mast which are amazing but soo exspensive. they do make bordix BR7 275cc intake LS7 heads that flow 410cfm assembled they are 3200 titanium intake valves, but minus springs rocks etc so probably 4500 all together maybe 5k,



the block, machining, and rotating assembly will cost around 6500+ plus lifters pushrods so probably around 12000-15000 total 3500 means 1000 on machining which seams high idk how much machining needs to be done and my friends are machinists so this could be much lower cost to machine the block haha

for now ill just run ported ls3 heads on a stock lq9 and the speedmaster ITB intake with headers and a cam and some valve train upgrades should make 500fwhp which is enough for now

then build the 421 dart long block and run that then get racing heads I cant do this all at once im not so billionaire haha but im not as obivious as you may think " I want 1000rwhp daily for about 2000 dollars"