[dre1984]

I have a big block chevy 396/402 bored to 408 and I am using it for the street mostly track. I am removing the stock 3.76 inch crank and replaceing it with a 4.00 inch crank making it a. 434. I am using 6.135 inch rods with keith black 11.5 pistons I have stock cast iron heads with big oval ports 2.19 and 1.88 inch valves bowel work and port gasket match on both intake and exhaust side. I am using a dart single plain intake with 950 holley carb with headers. So my question is do u think its possible to reach 600+ horsepower with good torque and what may be the best cam for this setup thanks

 

[alittle1]

In a word, NO!

You are going to run out of air. You won't have enough valve clearance with any large opening cam to supply the air you need.

I f you want 6oo horse, lower the compression and put a twin screw turbo or blower on it.

 

[Guy Hiltz]

If that 4 inch crank is a stock 454 peice,you will need to have the rotating assembly properly balanced,and use the correct balancer and flywheel/flexplate.The 454's are externally balanced,396,402 & 427's are internally balanced.
Guy

 

[dre1984]

All motor is what I had in mind for now is there another way to make 600+ with that motor size

 

[techinspector1]

Another fellow with a 10.5 408 PM'd me and asked me to DynoSim his combo. Might be you under a different screen name, I don't know. Anyway, here's my reply. Power figures shown will be dependent on getting the heads to flow according to the flow figures I listed.....

His question.....
I Have 408 Cid BBC. (396)
10.5 compression.
GM Rect. port 990 heads, heavily ported with 2.19"/1.88" valves.
Solid roller camshaft. - http://www.compcams.com/Cam_Specs/C...x?csid=501&sb=2
Edelbrock Performer RPM dual plane manifold.
Quick Fuel 850 CFM
Comp 1.7 Roller Rocker arms.
Electric Water-pump
4-2-1 Large tube headers
I would be glad to know circa how the engine performs and what kind of torque converter it would be best to use and so on.
Best regards And Take Care.

My reply......
Link to the cam was bogus. Ran the combo with a few of the cams I like. See how this grabs ya....
http://www.compcams.com/Cam_Specs/C...x?csid=511&sb=0
RPM HP TQ
2000 152 400
2500 198 416
3000 253 443
3500 331 496
4000 411 540
4500 491 573
5000 557 585
5500 596 569
6000 622 545
6500 625 505
7000 615 462
7500 588 412
Peak volumetric efficiency 102.2% @5500
Peak BMEP 216.2 @5000
I hope you can run good fuel with this. You'll need it.
Use a 3800-4000 converter.
Used these head flow figures.....
.100 72 59
.200 143 113
.300 215 139
.400 261 165
.500 290 186
.600 306 204
.700 323 213

 

[alittle1]

Quote: I am using 6.135 inch rods with keith black 11.5 pistons I have stock cast iron heads with big oval ports.

If he's using 11.5 pistons, he will be 'zinging' the valves at 6500 rpm's. Those heads will run out of air.

I would suggest that he do more thinking, before he buys anything more.