64post

iTrader: (5)

It won't be a tow truck motor.

big hammer

Thanks man. Sometimes it's hard to find time to work on it but I got it nearly done. You get yours in a car yet?

NAVYBLUE210

Going to be 6 months before Engine install at least. Still have many
Steps to prepare Drivetrain,Suspension, and break in a new clutch
Before installing the 396" in my C5.

NAVYBLUE210

Darth,
The split is all about the E/I Relationship.
Speaking NA The MAST Medium Bore LS3s are one of the best
LS3 Heads out of the Box IMO, comparing E/I relationship
From .300"-.600" is 84%-70%
My MAMOFIED TFS LS3s are 83%-68% (with slightly higher gross #s)
The MAST Big Bore 280CC Runners are 70%-64%
MMS 220s,235s are 85%-75% again at the same valve lifts
.300-.600".
So you can see the MAST Med Bore Heads have a E/I relationship
Much closer to MMS Cathedrals VS even Good aftermarket Square Ports.
Point being 6*-10* is probably the sweet spot for efficient E/I
LS3 Heads NA from 7000-8000 RPM.
VS the more typical 12*-16* splits seen with OEM Rectangle Ports.
In Big Hammer,s situation 14* will help carry beyond 7500 RPM
and only be a little soft below 3500 RPM (VS 10* split) which
I am sure he could care less about.
We are "almost" splitting hairs at this point.
I always value and get a lot from your threads & posts.

Darth_V8r

iTrader: (4)

I should have clarified. For carrying past peak I tend to see larger splits. Especially on rectangles. For hammers rpm goals, we sorta came up with something close to what he ended up with. In the end, Kip speced it out for him. But I also tend to like more exhaust in general. I like to open that valve early to vent the chamber down sooner. Then if you maintain any overlap at all, you end up 8+ split.

Look at it this way. If you do 45 IVC and 55 EVO and zero overlap, you'll get 10 degrees split.

For high revving, gotta open that valve to make room for fresh stuff!

And the respect is mutual my friend. I'm just really excited to see where hammer ends up. At 5 CI more than the every day 383, this thing is going to really shine vs the 383. Imo 3.62" stroke is plenty for torque. I feel like GM got that one right.

SoFla01SSLookinstok

Come on darth. I thought we weren't going to compare this motor to a normal 383. Which is completely different. Lol.

I have to check my phone & see how many tow jobs came in. Lol.

big hammer

I emailed mast to see if they knew what these heads flow on a 4.125" bore. They advertise fnumbers for a 4.070 bore. Short answer they don't know for sure, just "more". Lol

Tuskyz28

Darth... a well RESPECTED cam/head guy told me on the phone about camshafts with rectangle heads.
On the dyno the wider split cam performs well and usually makes the most power... but in the real world at the drag strip they run like crap which leaving people scratching they heads

Motor pushed 600 horses on the dyno but at the track it only e.t what a 500 horse car runs.

Basically what looks all good on paper isn't milk and cookies at the drag strip......

So in my words you have to be very careful with splits.

HioSSilver

iTrader: (8)

Idk....my ls6 has a super wide split. It seems ok at the track.


I'll be looking for 625-650whp out of hammers build .

jhshnh

I have normally don't do the guess my dyno thing, but this build is too interesting not to. 615 is my guess.
Either way, I'm sure it'll be a monster!

Darth_V8r

iTrader: (4)

I hear you. But I SERIOUSLY doubt that'll be the case on this one. I think this one will shock some bigger cube strokers.

big hammer

So like a 383 stroker....?

Mph shows hp. Et shows track efficiency.

I've only been to the track like 4 times in my life and almost always with different setups. So track efficiency I don't reallly have a handle on yet

Tuskyz28

6.0 Motor with LS3 heads mainly..... pm me and I'll tell you who mentioned it to me. He also said the rectangle port heads are very sensitive to overlap which makes them even harder to cam "sweet spot". I know mph shows hp. Hell it's a 427ci on here that traps 131 mph and runs 10.7 to 10.9 e.t. On the other hand it's ws6 on here traps 129 at runs 10.5 over and over. Both 6 speed F body cars.

HioSSilver

iTrader: (8)

Both should be faster unless they are retarded heavy.

SoFla01SSLookinstok

It actually does go deeper than that there buddy.

Keep on living & maybe you learn a little.

You should be less of a douche.

Oops, I acted like Hio..

Dark Energy

If a guy's running 131 on the top-end with a 10.7. Whats the 60 foot? The rear gear? and car weight? Car sounds soggy on the launch and not Properly set up for the track.
Hell John B. did 10's in the Monte Carlo and made 700 rwhp so does he need to re cam the car. There are many factors for the track and each car & build is different.

big hammer

I think I've read the same thing from the same person. For one supoosedly the intake valve is crammed to close to the cylinder wall on a 6.0. And given the size of the port and intake\exhaust bias, I would imagine that you could end up with port reversion quite easily if you don't have your combo set up properly.

Doesn't mean ls3's are crap, they just have their place. If you're goal is to build a 6.0 with the intention of shifting around 6500 I'd be more apt to stick with a stock cathedral casting over a stock ls3 casting. But if you want to build a 6.0 to rev to 7500-8000, ls3 me all day

Tuskyz28

car on YouTube.... 427ci with 235 TFS heads in a full weight SS built by vengeance racing.
On the other hand the car was on drag radials and was sideways for the first 60ft out.

big hammer

I think that 383's get a bad rap... well for one they generally perform no better than 346's. It's an under square engine making it hard to feed properly in a 2v configuration. Doesn't mean it can't be done. It just usually isn't. On a 383 I'd rather have a 250cc port that flows 310 cfm over a 230cc port that flows 310. On a 346, the opposite.

Since long stroke small bore by nature tends to increase volumetric efficiency, I bet set of mast small bore ls3's on a 383 engine would make a killer engine.

Tuskyz28

383s get a bad Rep cause the guy don't know how to pick the correct heads and cam. Richard Holdnerer did one.... It produced 605hp at the crank using TEA heads and a 239 duration cam.