prochargedpony

iTrader: (6)

Well, I am in a huge bind. Short block in my z is totally trashed. I don't have 1600 laying around due to a move going on, and I don't want to have a non running car.I found a 25k mileage shortblock from an 04 chevy truck for 250.00. Will I lose alot of power going to this short block, I still have my cam, ls6 intake, and stock 241 heads. If i am only loosing 5-10hp, I am fine.

I also found an LS1 short block for 300 but it has a broken head bolt, I am kind of leary on that one. Which should I do

rich5368

iTrader: (2)

With a bone stock 5.3 you're rated at 295 hp and a right about the same torque wise. Car Craft did an article with a junkyard 5.3 where they stuck some heads and a cam in it and made somewhere over 400 with it. If you get a look at the LS1 and the broken bolt can be safely removed without jacking up the block I'd go that route just for the aluminum block and more cubes, but the 5.3 is not a bad engine at all. It just doesn't have the overall potential that the bigger cubed LS does.

89tang

iTrader: (15)

From what i have read on the hybrid section on here (ls1 in a mustang etc. etc.) alot of ppl. go the 5.3 route cause you lose like 5-10 hp which isn't enough to offset the cost of a 5.3 and a true ls1. Actually a buddy of mine has gone the 5.3 route cause he got a complete 36k 5.3 for like 500 bucks shipped to his door.

garygnu

are the 241s valves too big for the 5.3 bore?

prochargedpony

iTrader: (6)

My main concern to be honest is cost. I actually can get the short block for 200, but I was told with the 241 heads my compression will be around 9.1 so it will be a dog.

89tang

iTrader: (15)

I don't believe it would be a problem i'm not sure about 241's on a 5.3, but you could mill your heads to raise compression that's like $50. And you save like 65lbs by going with an aluminum block also so weight isn't that much of a difference either.

garygnu

use a thin head gasket also.

prochargedpony

iTrader: (6)

i am more leaning towards the 5.3 motor, every machine shop i called makes it out like they will **** up my motor trying to get it out. this is so damn thrilling.

89tang

iTrader: (15)

Whenever i get the funds for my stang i will be doing a LS1 swap but i'm going to use a 5.3 block also. When you can still easily get 400+rwhp with the same mods you put on a 5.7 i'm like you the 5 or 10hp difference means nothing to me.

one fast zo6

iTrader: (490)

i would use the 5.3 and just mill your 241 heads .25
sould make around 360rwhp GL

prochargedpony

iTrader: (6)

That sounds doable, having the heads milled is no big deal. I was just alittle nervous about it being only 9.1!!!!! With those stock heads, that was texas-speed telling me that, and i know they know what is up. GM should have just put alum blocks in all their cars!!!!!! lol

prochargedpony

iTrader: (6)

okay, is this good or bad, the block is an l33 so it is the alum 5.3.....

pdbq

iTrader: (7)

If I ever blew up my LS1 and could get an L33 5.3L for under $300, I'd be all over it in a heartbeat. I'd prefer to use the stock 5.3 heads and mill them for a bump in compression and/or use 4.8L pistons (flat tops) as someone else here in this thread: https://ls1tech.com/forums/generatio...l-pistons.html

prochargedpony

iTrader: (6)

it will be here on friday it is actually a complete motor, but one of the heads has a crack on the top by the valve cover valley. I work for a body shop and this is from a vendor of mine. I just happened to get lucky that this was an alum 5.3 motor.

rich5368

iTrader: (2)

Could go with the PRC stg 2.5 5.3 heads at TSP. Have em set them up with so your CR is more like 9.5:1 or even 10:1 and you'd have yourself a little monster 323 on ur hands.

prochargedpony

iTrader: (6)

my compression is already 9.9. If i had the money for the stage 2.5 5.3 heads, I would buy a complete pull out motor for my camaro. Just isn't doeable with my move going on, paying 1500 for rent and deposit, plus renting a truck and buying alot of beer and pizza for my friends lol.

rich5368

iTrader: (2)

Well then stock replacements can be had pretty affordably. Add a cam and your in the mid 300s at the crank.

garygnu

get a LSr truck cam from comp,54-455-11.it has 5* of advance ground in.it would help raise you DCR,lots of low end torque.

LSX92Stepside

The guy needs a complete motor, not a cam or set of heads. For $300, just do the 5.3l and change out to a LS1/LS2 later. Sounds like you just need something in there without headaches. I would skip the ls1.

pdbq

iTrader: (7)

I have a friend with a stone stock iron 5.3L in a 93 Camaro. With the automatic + full bolt ons and he runs 13.0 @ 107 mph. Most stock LS1s run those times or maybe a tad better with full bolt ons. I'm really digging the 5.3s now!