Stroker combo with cathedrals
Thread Starter
Teching In
Joined: Jun 2011
Posts: 7
Likes: 0
Stroker combo with cathedrals First post and I hope it’s not too long! Wanting to build a shortblock this winter and add my current cam and heads to it. Currently running cam motion junkyard dog cam with mild ported 243s Vic jr and pro systems 800 on a lq4. What is the cubic inch limit with cathedrals? Considering building a 408 iron or an alum block 383. Which combo would work best with my current top end? This is in a street strip
Fox body.
Fox body.
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.
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.
Last edited by 99 Black Bird T/A; Oct 17, 2018 at 09:15 PM.
Trending Topics
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.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
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
Teching In
Joined: Oct 2018
Posts: 3
Likes: 0
Crank First post and I hope it’s not too long! Wanting to build a shortblock this winter and add my current cam and heads to it. Currently running cam motion junkyard dog cam with mild ported 243s Vic jr and pro systems 800 on a lq4. What is the cubic inch limit with cathedrals? Considering building a 408 iron or an alum block 383. Which combo would work best with my current top end? This is in a street strip
Fox body.
Fox body.
