Generation IV Internal Engine 2005-2014 LS2 | LS3 | LS7 | L92 | LS9
View Poll Results: 421 or lq4
421 stock hand ported heads
57.14%
lq4 stock bottom end aftermarket heads
42.86%
Voters: 7. You may not vote on this poll

421 vs lq4

Thread Tools
 
Search this Thread
 
Old Aug 4, 2009 | 06:11 PM
  #1  
novaflash2002's Avatar
Thread Starter
TECH Enthusiast
iTrader: (51)
 
Joined: Jul 2008
Posts: 616
Likes: 0
From: Billings, Mt
Default 421 vs lq4

Well im in a bit of a delema. I have two optiions that i will be doing for myself finaly but cant decide what to do. I would either build a 421 (which i already have everything minus machining done) or a stock bottem end lq4 with some bad *** after market heads (thinking darts or trick flow). In the end it will cost the same. the reason i am starting a little poll is to see how may guys have or have had problems dding their stroker. I drive my car about 25000 miles a year. about 50/50 as far as intown and hwy. most of the intown miles are 15 miles one way. Im not worried about cam specs just seeing what would be the best. O and its going into a gto with an auto. thanks
Reply
Old Aug 4, 2009 | 09:10 PM
  #2  
Fbodyjunkie06's Avatar
10 Second Club
iTrader: (10)
 
Joined: Mar 2009
Posts: 4,712
Likes: 5
From: Greensboro, NC
Default

421 with ported l92 heads and a ported L76 intake manifold with a nice 232/236 60x/60x 112 lsa cam would get you very close to 500 rwhp I'd say if not a reasonable 470-490. And if you wanted a smaller more DD friendly grind a 228/230 or 228/228 58x/59x on a 114 lsa. I think that would still net you very close to 475 still with that setup and I think thats still a little low depending on the dyno you use and it will all be in the tune too as to what you make in the end.

Just saw it was an auto I'd say a Yank or Vig 3600-4000 stall for the bigger grind I mentioned and a 3200-3600 yank or vig for the smaller grind would do nicely on the street I'd think. Don't forget a good tranny cooler you'll need it.
Reply
Old Aug 4, 2009 | 10:17 PM
  #3  
novaflash2002's Avatar
Thread Starter
TECH Enthusiast
iTrader: (51)
 
Joined: Jul 2008
Posts: 616
Likes: 0
From: Billings, Mt
Default

nice info, i would probably stick to 5.3l heads that i will port myself (done a couple) put 2.02 1.60 valves in.

keep it coming.
Reply
Old Aug 4, 2009 | 10:31 PM
  #4  
MelScrilla's Avatar
TECH Fanatic
iTrader: (2)
 
Joined: Mar 2009
Posts: 1,139
Likes: 0
Default

i like the 421. will the 5.3's flow enough to feed a 421
Reply
Old Aug 4, 2009 | 10:38 PM
  #5  
novaflash2002's Avatar
Thread Starter
TECH Enthusiast
iTrader: (51)
 
Joined: Jul 2008
Posts: 616
Likes: 0
From: Billings, Mt
Default

just a decant power street engine. im not looking for a race engine and yes i have got over 3xx cfm on the intake and 2xx cfm on the exhaust with 5.3ls at .600 lift
Reply
Old Aug 4, 2009 | 10:54 PM
  #6  
one fast zo6's Avatar
TECH Resident
15 Year Member
iTrader: (490)
 
Joined: Jan 2008
Posts: 791
Likes: 0
From: Austin, Texas
Default

the more torque the better in a heavy GTO the more ci the better, but
you know that!!!
Reply
Old Aug 7, 2009 | 06:39 AM
  #7  
Bader-X's Avatar
TECH Apprentice
iTrader: (2)
 
Joined: Apr 2006
Posts: 386
Likes: 0
From: Kuwait
Default

I vote stroker


the reason:
370 with aftermarket heads (not LS7 or very large ports ones) with X compression and set up specced cam
vs
421 with stage 2-3 243 from the popular and proven vendors/L92 stock or ported with the same X compression and a set up specced cam

I say 421 wins and if the price is the same would like to be driving the 421 ^_^

{--- cooking 418 with PRC 2.5 317 (6.0 LQ9 heads) *because of +5 dome piston used short block

and if I were there in the USA I would`ve used PRC 5.3 2.5 if I didn`t have dome pistons and choose a piston according to my desired compression and money was an issue and looking for the best bang for buck ....or ..... use the hand ported or stock ones untill I can afford the heads I want

hope it helps and good luck with whatever you choose

Last edited by Bader-X; Aug 7, 2009 at 06:57 AM.
Reply
Old Aug 7, 2009 | 11:34 AM
  #8  
novaflash2002's Avatar
Thread Starter
TECH Enthusiast
iTrader: (51)
 
Joined: Jul 2008
Posts: 616
Likes: 0
From: Billings, Mt
Default

i preaty much made up my mind on doing the 421. for the time being ill just put a smaller cam like a torquer 2 or 3 in, ill do up a set of 5.3l heads to bump up the compression a bit.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo




All times are GMT -5. The time now is 06:29 AM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE