[81malibuman]

I'm building a 406 and was wondering if this combo would be good and how much horsepower it may be!

scat 9000 series 3.75 stroke crank
scat 4340 5.7 i beam rods with bolts
10.5 to 1 forged dtep dish pistons
aluminum 210cc heads 2.02 and 1.60 valves 64cc
hydraulic roller cam with following specs

int. exh.
duration lift 296 300
dur. @.50 234 238
lift 539 548
lsa 112*

victor jr. single plane intake
825 demon carb
3200 stall with 4.11 gears in a stock suspension 81 malibu

thanks any comments would be appreciated or if there is anything i should change please let me know

[68NovaSS]

10.5:1 dish pistons? A piston sold or labeled as a particular c.r. is a WAG at best. What's the dish volume in cc's?

Moving to Basics for power estimates, you should get some answers there.

[81malibuman]

15.2 cc step dish piston

[68NovaSS]

With limited information, not knowing piston compression height, etc, with a .041 gasket, 4.155 bore and the piston at zero deck, with 10.44:1. With the piston .025 in the hole I get about 9.88:1.

Here's a calculator for reference.

[81malibuman]

im just going by what the manufacture says.they are icon forged pistons on there website for a icon 754 piston which is a 15.2cc dished flattop is 10.5 to 1 with a 64cc head so what would it be i think you have lost me somewhere. are you saying that i will be fine with a flattop piston?

[techinspector1]

833.22 cc's in the cylinder
66 cc's in the head (they usually pour larger than advertised)
3.11 cc's in the piston deck height (assuming a stock block deck height of 9.025" and a stack height of 9.011") (1.433" piston, 5.703" rod, 1.875" crank radius), leaving a piston deck height of 0.014".
15.2 cc's in the piston crown
8.85 cc's in the Fel-Pro 1014 gasket (recommended by Airflow Research for their aluminum heads) 4.200" X 0.039", so the squish will be 0.053".
All totalled up- 926.38 cc's
Drop out the cylinder volume- 93.16 cc's
Divide the larger by the smaller and find 9.94:1 static compression ratio.
Be sure to drill the heads for steam holes....
http://www.gregsengine.com/convertin...ds-to-400.html
Math doesn't lie, it's black and white, no gray areas.

Now, if you'll post the flow number on the heads and the part number and mfg of the camshaft, I can run the motor on the DynoSim.

[81malibuman]

eldebrock hydraulic roller edl-2201

flow numbers

--- int. exh.
100 63.0 52.2
200 117.1 97.8
300 163.1 132.9
400 203.55 161.9
500 230.3 180.0
600 248.2 189.2
700 252.2 192.1

if its not much trouble could you also do a test for me using comp cams 274 extreme enegy solid roller part# 12-700-8

dur.
int. 268
exh. 268
@.50
int 224
exh 224
lift
int 525
exh 525 with a lsa 110*

Thank you

[techinspector1]

Edelbrock cam retarded 2 degrees works the best. Tried several other grinds, including the comp solid you asked me to try.
First, I ran the Victor Jr intake
RPM HP TQ
2000 163 428
2500 211 443
3000 260 455
3500 316 474
4000 361 475
4500 398 465
5000 416 437
5500 409 391
6000 360 315

Then the Edelbrock RPM intake
2000 164 429
2500 206 433
3000 262 458
3500 323 485
4000 377 495
4500 418 488
5000 450 473
5500 450 430
6000 400 350

[81malibuman]

thank you tech inspestor you are a big help with lots of information to lots of people! my engine is at the machine shop getting freshend up i plan to get the rpm air gap. thanks

[techinspector1]

I wouldn't us the Air Gap model unless I lived in a really warm climate. The standard RPM will do the job and will warm up a little quicker on those cold Kentucky mornings.

[81malibuman]

how much will it help if i port my heads and intake? how much compression should be the max with aluminum heads on the street?

[techinspector1]

Originally Posted by 81malibuman

how much will it help if i port my heads and intake? how much compression should be the max with aluminum heads on the street?

Power is in the heads, but it's a balancing act. If you don't have a good cast of supporting actors in the mix, your star will not give a good performance.

As far as max SCR on the street, I like to be around 9.5 with iron heads and not over 10.0 with aluminum. I know there are fellows who will run more, but I would rather be conservative and be safe if I take on a bad load of fuel. If a fellow isn't smart enough to make a ton of power at 10.0, then he probably isn't smart enough to make it at 11.0 either. The more compression you use, the more cam you have to use and pretty soon, you're out of the street motor neighborhood.