Originally Posted by 1Bear

My knowledge of the Gen VI L29 style Vortec 454 heads are that they are of a large oval design with basically 100cc combustion chambers. Like Richard mentioned, I would stay with a reasonably small camshaft unless you were to convert the heads from the net-lash rocker set-up that they were equipped with. You can convert the heads from the net-lash configuration that the Gen V & VI’s use by drilling and tapping the factory 3/8” rocker bolt holes out to the 7/16” bolt holes that the Mark IV’s used. When doing so you will then have to use the adjustable rockers, pushrod guide plates and pushrods from the Mark IV. You could also use a conversion stud arrangement, but there again if you were to do so, you would need to limit your cam size as the conversion studs will not handle too much spring pressure before failing. They are actually pretty good heads and can be quite a performance booster to most of the smog era big-blocks that originally came with either the peanut style ports or 119cc heads that resulted in them having 8.5:1 compression, in most cases they were saddled with both the small heads and low compression. They respond well to adding the larger 2.19/1.88 valves in place of the stock 2.07 / 1.72 pieces, yet may be unnecessary in a fairly low RPM configuration. The L29 intake is not that bad and the injectors are of the same type as the L98 small-block, so there are plenty of options for larger injectors. The intake consisting of a lower and upper configuration lends to access when porting is deemed necessary. I would concentrate on a healthy lower RPM set-up as the PCM in the ’96 to ’98 models as everyone knows does not allow anything over 5800rpm anyways. Bottom end components can be purchased and assembled as you would with any traditional big-block, the only major difference being that the L29 454 has a one-piece seal crank and as such has particular balance requirements.

Originally Posted by tank454

Thanks a lot guys. If I were to try to make 400hp, what size injectors would be able to handle that much power and fuel? I have much more experience with Duramax motors than big blocks and I have used FASS fuel systems and upgraded CP3 pumps and added a large amount of power. Can I use parts similar to those to increase my power potential?

Originally Posted by Big Red Truck

I have been a big block junky for years.

How much money are you willing to spend?

I might be able to help you, if you like.

Originally Posted by stock48

No totaly different animal. To add power to a NA gas engine you need to increase airflow, in and out of the engine with a bigger camshaft, better flowing heads, Cubic inches, headers, intake, TB etc.

With a diesel you do it with Turbo, boost, injection timing, fuel rail PSI, and volume. You don't need to mess with the cam and heads until you start making BIG power.

You can build a nice 496CI with the Brodix heads, ported intake, 225*/234* @.050'', .573''/.600'', 112* Isky cam that should make ~450HP/500TQ with the fuel injection. It will run strong but won't hold a candle to a 400~500HP Dmax that makes 800+ lbs of tq.

If you want to run with a tuned Dmax and keep it NA, you will need at least 650+HP. You can easly make that with a NA 500CI BB with the Brodix heads but it's going need at least a 244* @.050'', .650'' HYD, or SLD RR cam, and aftermarket fuel injection like a fast system, or switch to a carburator. It will be streetable but on the nasty side for a daily driver.

Another option that I just thought of would be to run that mild fuel injected 496, and hit it with a shot of N20.

I have a NA 505 CI (factory 454 block 4.350''X4.250'') Ported factory #049 iron oval heads, Isky 244*/250* , .650''/.636'', RPM air gap, holley 950HP carb that makes 650HP, and 686LBS (flywheel). It runs mid 11's in shitty conditions in my 5000LB lifted 1970 chevy K20 4x4.

Originally Posted by xXxSilveradoxXx

F keeping the big block NA! Turbo that bitch!