400ci
TECH Fanatic
Joined: Aug 2011
Posts: 1,324
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From: Marengo, Ia
Hot rod tested a pair of stock ls3 heads on a 468 stroker and made something like 690 horses. Stock heads. Clean up the exhaust ports and run about 11.5 compression and cam correctly for the street should make more that a ls3/l92 combo. If a 468 can make that power at 6900 rpms then a properly cammed and headed 400 with a 4.185 bore should be a blast. I'm only adding bore over an ls3 combo. I have plenty of opinions but no real answer.lookin for the y and y not.
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It will be if you get a smallish cam and enough compression but you'll need relatively small heads for it to be really snappy, and at that point you're wasting all the benefits of the huge bore. If you put a big valved 450cfm head on there it's gonna be lazy as heck for 400 cubes. If you put in a smaller head then it's going to not make as much power on only 400 cubes.
But as said before, a different setup with a longer stroke and even smaller bore will make more torque and power. A proper setup 416 will kill it in torque and snappiness and make more power up top to boot.
But as said before, a different setup with a longer stroke and even smaller bore will make more torque and power. A proper setup 416 will kill it in torque and snappiness and make more power up top to boot.
For the cost spent, you won't see much benefit over just a stroker LS2. The added bore opens up more head options, but most of them need more CID than you'd be giving them.
I'd also use LS7 heads on something with that much bore.
Preferably, I'd do a 4.185" bore with 4.125" stroke and spin the 454 to 7500 all day with some aftermarket LS7 heads and aim for 700rwhp all motor.
I'd also use LS7 heads on something with that much bore.
Preferably, I'd do a 4.185" bore with 4.125" stroke and spin the 454 to 7500 all day with some aftermarket LS7 heads and aim for 700rwhp all motor.
If the high short block cost causes you to be limited to LS3 heads with only the exhaust ported then you'd probably be better off with a LS3 based 416 and much better heads. The longer stroke would build more low end torque and the better heads would make more top end power.
Clean up the exhaust ports and run about 11.5 compression and cam correctly for the street should make more that a ls3/l92 combo.
But like mentioned, a 416 with those same heads will blow your 400 out of the water everywhere in the curve and be significantly cheaper.
I have plenty of opinions but no real answer.lookin for the y and y not.
