What are the specs on that cam? Typically when you add cubes but dont change the top end, you add torque and shift the power band to the left

 

I say build for as many cubes as you can.

 

Junkyard Dog Single Plane Cam- 232/244, .621/.604, 111LSA, +4 deg. adv.

 

 

 

Definitely agree.

My 383 LS1 is a very fun well mannered street engine. The top end is what was pretty typical back in 2002/2003 for a heads & cam LS1. It peaks at 6,000 rpm instead of 6,500 rpm and makes an extra 40 foot pounds of torque at the wheels and like maybe 10 more hp. The 3.9 bore limited the valve size to 2.04 and on TEA's flow bench 320 cfm. The exact same head on a 4 inch bore flowed 330 cfm with 2.08 valves. Depending on cam selection etc definitely more potential power with the bigger bore.
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Like Darth & KCS said go for max cubes and bigger bore more for more hp and power. The 408 with a 4.030 bore and 4 inch crank is an extra 25 cubes over a 383 LS1 that will allow more cam. With a 4.030 bore and 4.125 crank it's a ~421, 38 more cubes than a 383 LS1.

Unless some sort of class rules require a 3.9 bore or its a just for fun resto-mod toy like my 91 RS, it's very hard to make a logical argument in support of a 383 LS1 these days. Getting the extra ~100 pounds off the front of the RS was good for handling.

BTW - Thompson Motorsports has a sweet sale going on for 408 short blocks.

 

Just be aware, that theoretically a bigger valve will bleed back into the head at low lift more than a smaller valve will. So valve opening and closing rates are important with that bigger valve and a custom cam may be a better choice.

 

What size crank u plan on using

 

That cam is too small for a 400 plus cube stroker. Get a cam custom cut to the weight, gearing,etc of the car.

 

 

I made 507 rwhp and went 10.80's with my 416 ci motor with stock 799 heads and a fast 102

 

Thanks for the bump!!!