408ci Dyno
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 58
Likes: 6
From: North Carolina
TECH Veteran
Joined: Sep 2014
Posts: 4,892
Likes: 703
From: Mississippi
Bortous- The motor is making 1.5 horsepower per cube. Thats where most people WANT on pump gas and anything over that takes some serious attention to detail/optimizing. The op is making great power in my opinion. Those 700 horse 40Xci motors are solid roller, race gas or E85 etc....
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
TECH Addict
Joined: Sep 2010
Posts: 2,898
Likes: 467
Bortous- The motor is making 1.5 horsepower per cube. Thats where most people WANT on pump gas and anything over that takes some serious attention to detail/optimizing. The op is making great power in my opinion. Those 700 horse 40Xci motors are solid roller, race gas or E85 etc....
That is one big *** camshaft for a 408.
I was just mentioning the torque curve that's all.
It peaks at 4800rpm or so then begins falling off but by 6000rpm it falls off a cliff.
I was expecting it to hang on better in the top end with all that exhaust duration but if falls off a bit too quick.
TECH Veteran
Joined: Sep 2014
Posts: 4,892
Likes: 703
From: Mississippi
The power output is as expected.
That is one big *** camshaft for a 408.
I was just mentioning the torque curve that's all.
It peaks at 4800rpm or so then begins falling off but by 6000rpm it falls off a cliff.
I was expecting it to hang on better in the top end with all that exhaust duration but if falls off a bit too quick.
That is one big *** camshaft for a 408.
I was just mentioning the torque curve that's all.
It peaks at 4800rpm or so then begins falling off but by 6000rpm it falls off a cliff.
I was expecting it to hang on better in the top end with all that exhaust duration but if falls off a bit too quick.
TECH Addict
Joined: Sep 2010
Posts: 2,898
Likes: 467
The cam is big but then again its not too crazy. Ive done lots of research and development personally. The average guy that builds a 40Xci motor with cathedral heads is running a 244-251 cam. Usually these cars run 10s at the track. Look at YOUR thread where i posted those different stroker combos and look at those cam specs....
An extra 5 degrees of on the intake make it about as much as a square square port.
The exhaust duration is overkill for that head which still begs the question why the torque fell off too soon.
maybe it would have performed better with less exhaust duration?
Who knows.
I disagree with the torque falling off too quickly. Never seen a dyno that the torque was level and HP did not keep increasing.
Looks like peak tq at 4900 and peak power at 6500. A 1600 rpm power band is good.
Looks like peak tq at 4900 and peak power at 6500. A 1600 rpm power band is good.