[Hawk397]

What do you think?

400 bored 40 over with a set of ported/polished 6x-4 heads and a custom grind cam topped off with an Edelbrok Performer intake and 750 cfm carb. Tuner had generic headers on there.

Peak Torque: 448ftlbs @ 3900RPM
Peak HP: 369HP @ 4800RPM

Thanks!

Mark

[Hawk397]

What do you think?

400 bored 40 over with a set of ported/polished 6x-4 heads and a custom grind cam topped off with an Edelbrok Performer intake and 750 cfm carb. Tuner had generic headers on there.

Peak Torque: 448ftlbs @ 3900RPM
Peak HP: 369HP @ 4800RPM

Thanks!

Mark

[tom s]

what cam,HP peak RPMs seems low.Tom

[Jeff Walker]

Kinda hard to say without knowing more details on your engine combo..ie cam specs, compression ratio, ect.

[Hawk397]

It's right at about 10:1 on compression. The rockers are roller 1.65's, Hydraulic lifters and the following is what I have on the cam @.050
Duration: 200 & 225
Lift: 310 & 305
C/L: 106

I'm used to my LS-1 Corp engine specs and those cam numbers look very "odd". Is it just me?

[tom s]

seems like a small cam,low lift and tight LC.Would not have been my choice for ported heads.Do you know the flo numbers on the heads?Tom

[Bad Karma]

Id buy a new Cam Brother. That Seems Pretty Low lift. polished and ported heads call for a Higher lift cam to make use of thier flow rates.
Change cams and you'll see more than 420 Hp Id bet easy.

[myckee]

I believe those lift numbers are for lobe lift, and not gross valve lift. Assuming it to be lobe lift, then a comparable cam from Comp shows .462 and .470 as the gross lift numbers. Therefore I suspect the lift numbers to be in the range of around 450

[Hawk397]

That would make much more sense (I had the office gal read them off to me - she might have given me the wrong set) I also wasn't expecting a 106 C/L and the duration numbers seemed "average" at best. (Keep in mind what I'm used to - my 402 LS-1 stroker specs are: 240/245 610/620 on a 112. Before that I ran a very mild cam 221 - 558 - 114 in my stock LS-1)

How much gross lift does going from stock rockers to 1.65's add?

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by myckee:
I believe those lift numbers are for lobe lift, and not gross valve lift. Assuming it to be lobe lift, then a comparable cam from Comp shows .462 and .470 as the gross lift numbers. Therefore I suspect the lift numbers to be in the range of around 450 </div></BLOCKQUOTE>

[Jeff Walker]

If those are lobe lift numbers that would give you a gross valve lift of .511 and .503 with 1.65 rockers. Considering the small duration numbers your results aren't too bad IMHO.

[Ken -Ace- Brewer]

From all the motors I dyno, those are good #'s! You should pat yourself on the back and be proud.
Be Cool,

[Hawk397]

Thanks guys, I appreciate it!

Mark

[myckee]

hehe I had a bit of a brainfart when I posted earlier and couldn't remember how to get valve lift from lobe lift.

Anyway just multiply the lobe lift by the rocker ratio, and the total is the total valve lift.

lobe lift X rocker ratio = gross valve lift

[wk wood]

I threw your numbers in an engine computer simulator and came up with 376 HP @ 4800 RPM and and 437ftlbs @ 3800 RPM, pretty close!

Changing cams specs to something like a Pontiac 068 cam (dur 212/225, lift .450 lobe sep 115 advanced 2 degrees, I came up with 415 HP @ 5500 RPM and 455 ftlbs @ 4500 RPM.

Just food for thought.

[buwalda]

I think those are good hp & tq figures for the mild combination you have. I'll bet the '106' is not the lobe Centre Line [ LSA ], but the intake centreline. If it was ground with a 106 LSA, that would be unusual for such a small duration. The '200' & '225' don't look right either. Don't recall seeing as much as a 25 degree spread between the intake & exhaust duration. This cam would not be using your ported heads, better intake & headers to their fullest potential. A Comp Cams XE268 or XE274 would really wake it up.

[Hawk397]

Yea, nice gal in the office but I need to see the print-out on the custom grind!

This is primarily a steet application (so torque looks great) but I had a target of 12.8x on sticky tires for an occasional Pontiac's only race.

In case anyone is curious, the rest of the specs on the car are:
-Tri-y headers
-Race prepped 200R4 with a 2400 stall converter
-3.42's in the rear
-Holley 950 TBI setup at a later date.

Mark

[Skip Fix]

Depending on the dyno , if its conservative thaose are some really good numbers. My RAIV 400 made right at 385hp with more cam(UD 288/296) and pushed a 3850 TA to 12.60s @ 108

[Hawk397]

Sounds good, I'm not very familiar with engine dyno accuracy but this was a brand new unit that had just been installed and calibrated.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Skip Fix:
Depending on the dyno , if its conservative thaose are some really good numbers. My RAIV 400 made right at 385hp with more cam(UD 288/296) and pushed a 3850 TA to 12.60s @ 108 </div></BLOCKQUOTE>

[Bad Karma]

KEEP THAT cam card!!!!!!it will come in handy many times later&gt;

[Hawk397]

Yea, got the card and it makes a little more sense now!
@.050 = 220 / 225
Gross Lift (1.5rr) = 465 / 460
Lobe Center Separation = 106
Intake LObe Centerline of 102

This engine ended up at 9.5:1 with 1.65 roller rockers. Attached is a copy of the results from the engine dyno.