View Poll Results: Which one?
383
14
22.22%
408
49
77.78%
Voters: 63. You may not vote on this poll
383 or 408
Thread Starter
Launching!
Joined: Sep 2004
Posts: 246
Likes: 0
383 or 408 Trying to decide between going for 383 or 408. Which do most of your prefer? I hate the idea of adding 60-70# over what I have RIGHT IN THE FRONT of the car, but I am looking for low end torque. But which will give most power throughout? Is the 383 going to give better top end? Since this is a daily driver, I do not want ALL MY POWER DOWN LOW.
1. 383
2. 408
Thanks
1. 383
2. 408
Thanks
TECH Apprentice
Joined: Jun 2004
Posts: 355
Likes: 0
From: Houston,TX
Cast iron will take a mother of a beating as compared to aluminum. It depends on your setup. I wont put down aluminum because it is more efficient and disappates heat better. For blown, or big spray, I wouldn't trust an aluminum over time, even if it did have a forged bottom end. Just my $.02. 
Staging Lane
Joined: Aug 2004
Posts: 98
Likes: 0
From: Vegas, baby!
You can see the route I chose.
With a car that weighs 3,700lbs to begin with, what's another 85lbs?
I need the torque in a big way. I've lightened the car a bit, so the net gain should only be around 50lbs or so.
With a car that weighs 3,700lbs to begin with, what's another 85lbs?
I need the torque in a big way. I've lightened the car a bit, so the net gain should only be around 50lbs or so. Thread Starter
Launching!
Joined: Sep 2004
Posts: 246
Likes: 0
Originally Posted by Sam 04 GTO
what's another 85lbs?
My budget puts me right at getting the motor. Already have built 4l60, full suspension, TQARM, Relocation brackets, panhard, SFC, In tank Walbro, 42# bosche. What I dont have is TH400 and something better than stock rear.
I will just take it ez for a while. But now the question is: What provides better power throughout? Or is that more dependent on cam selection? I appreciate the feedback.
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TECH Senior Member
Joined: Nov 2001
Posts: 10,341
Likes: 1
I have a 385 and love it but I wouldnt mind a 408 either. The extra ~25RWTQ will be nice and noticeable especially for a street car.
You can offset the weight easily (K-Member, A-Arms, Hals etc) and the durability of the ironblock is great.
cant go wrong either way imo
You can offset the weight easily (K-Member, A-Arms, Hals etc) and the durability of the ironblock is great.
cant go wrong either way imo
Originally Posted by Chris ARE 385
You can offset the weight easily (K-Member, A-Arms, Hals etc) and the durability of the ironblock is great.
TECH Fanatic
Joined: Mar 2003
Posts: 1,112
Likes: 0
From: Dallas
Originally Posted by VINCE
I would run my 408ci against a 383ci car similar to mine any day..
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
LS1=91lbs
LS1 heads=20lbs each
iron block=183lbs
This according to the GM service manual. (Bare block and head castings)
Actually it is around ~92 pounds of extra weight.
All depends on your set up. Light car with 383 would be my choice, also I'm not too crazy about the difference in expension between Alum heads and Iron block, especially on nitrous.
with a forged bottom like a Callies crank and rods + ARP mains etc.... it would match 408 output if properly built.
LS1 heads=20lbs each
iron block=183lbs
This according to the GM service manual. (Bare block and head castings)
Actually it is around ~92 pounds of extra weight.
All depends on your set up. Light car with 383 would be my choice, also I'm not too crazy about the difference in expension between Alum heads and Iron block, especially on nitrous.
with a forged bottom like a Callies crank and rods + ARP mains etc.... it would match 408 output if properly built.
Iron blocks are durable, great for power adders(boost/bottle). Weight is an issue if you're always staring at your timeslip, wanting a better time. So if you're that person, be prepared to do offsetting mods to counter that extra weight(tubular K-member, shocks, et cetera). Talking about a TH400 you're pretty much a drag racer, so its not like you're gonna need to do a lot of cornering with this pig. A full suspension can always be tuned anyhows, presuming you got the good stuff The extra horses from the 408 over the 383, combined with the weight loss mods, should make up for the extra weight.
The extra horses from the 408 over the 383, combined with the weight loss mods, should make up for the extra weight.