the_merv

iTrader: (88)

You get a bigger Cam in there, and it will be a monster. That setup is very similar to mine, and mine has some crazy power at low RPM's as well..I have a bigger Cam..hopefully it puts down some nice numbers..

BOWTIE

Do not sale yourself short on compression unless you have some sort of future plans (i.e. forced induction). As long as you keep your DCR in check with valve events, compression will equate to free HP and a much better curve. One of the reason huge cam only motors make lousy torque down low is because of the mediocre compression which when combined with a large cam drops the DCR way too low.

N4cer

iTrader: (11)

Screw the dyno numbers. This isn't a ricer board. Ask what TIMES they're running! I wanna know since I'm putting a 408 in soon.

SS101

iTrader: (2)

well i'm planning on twin turbos and nitrous in the future, just can't come by the money right now . i'm pretty much a dope when it comes to cams...the numbers may as well be in chinese, but i asked around before and got these numbers from predator-Z

243/249 .629/.629 112+2 Lsa

i said i needed a good idle, plenty of power under the curve (road racing) and a high redline @ or around 7K. like i said, i don't know jack about cams, but i DO know that predator-Z is the man when it comes to cams.

the_merv

iTrader: (88)

Patrick G is another very helpful guy when you want a Cam. He spec'd mine.

Gannet

Run the numbers first. Big engines need big cams, big cams have lower DCR, all else equal. There's a reason everyone is running 11+. I think you'll find that 10:1 is too low.

slow trap

iTrader: (22)

you could build it pretty high compression for the time being with a set of 59cc heads and later down the road you could swap out the 59 cc heads for a set with 72cc chambers when you go fi.

Ryne @ CMS

iTrader: (10)

two motors in the works:
434 stroker, ported ls7s, 13.5:1 compression, 259-268 .658"int/ext 110lsa+0 custom grind comp. numbers soon.
this motor is already completed just not in the car.

438 stroker, World product ls7x warhawk heads, 11.5:1 compression, 242-248 on 112+4, numbers soon as well

SS101

iTrader: (2)

that's a good idea gannet...i might just do that

do you think it would make enough ower to justify the cost of another set of heads tho? if we're talking ten of horsepower then i may just take the hit in the wallet

jeremym

iTrader: (3)

414ci with 244/248 cam, TFS 235cc heads 11.8 comp 545rwhp 510rwtq in a street car with A/C. With 475rwtq at 3000rpm

brokeTA

iTrader: (9)

Two recent 403/408 builds that we have completed.

403/L92 cnc heads, Pat G. cam with about 12.5 compression 544/498 through 28 in hoosier QTP's

408/L92 cnc heads TSP cam 12.75 compression 529/490 through a 12 bolt and 27 in et streets.

Both M6 cars, both running out of fuel.

Did another 403 not long ago in a 06 C6 vert, also m6 had out of the box l92's with a TSP giant on a 114 and 10-1 compression, and it did 501/478 through 1 7/8 lt's and corsa exhaust.

Also an auto 02 z28 with an slp shortblock, and out of the box l92's with a TSP giant on a 112 and a 9 in rear with a 3600 converter- 477/458 unlocked.

BOWTIE

This is the best idea I've heard yet for what you want. Get a set of cheap stock castings, ported and milled to get thye compression up with your piston choice. Then when you are ready, splurge on the best set of heads you can afford (or possibly some L92's) with the larger chambers to get your compression where you want it for the boost. I would bet the compression will make much more than 10 HP difference peak, but more importantly, it will make the car more drivable and much less slugish down low.

WKMCD

iTrader: (2)

Already a monster. My car is 500lbs lighter than yours.

edcmat-l1

iTrader: (10)

Any more details on these? The 544 would be an L92 record i would think. For that small a motor.

Gannet

Compression is worth 3-4% per point. Plus better throttle response and fuel economy. Call it 4% and on a 500 rwhp build you're looking at 20 hp to move 1 point.

Let's assume a 427 with 59cc heads and a SCR of 11.73. Going to 62cc gets you 11.35, and 72cc yields 10.25. So you can move it a point to a point and a half with a head change. From an economic point of view, if you buy quality heads that are well-regarded, such as AFRs, then you should be able to sell them for 75-80% of what you paid for them.

N4cer

iTrader: (11)

Just to clarify:
I believe when people refer to a "point" on compression, they are referring to a movement of a whole number. As in 1 point is the difference in 11.0:1 and 12.0:1.

SS101

iTrader: (2)

would my DCR still be low enough to run pump 93??

SS101

iTrader: (2)

if i went with smaller heads, would i have to change my cam as well?

N4cer

iTrader: (11)

Most say 8.8:1 DCR is max with iron heads, and in speaking with some engine builders and head porters, I'm hearing 9.5:1 with aluminum heads.