00_Hotrod

An Engine w/ new parts r one w/ 100k to run hard, I vote for new parts, And These heads I have flow better than a stock 6.0 (317) head, Why would one spend more money buying a used engine when one can build one cheaper w/ more power..(More compression & better flowing heads)

joeyc125

iTrader: (7)

Who did the heads? any flow numbers? LSX heads are not as easily ported for big gains like old SBC or BBC heads are. It takes a very competent person with lots of experience in those heads to get anything, they actually are very easily screwed up and lose power! What kind of parts and who's installing them? 100k miles on a used engine is nothing for these motors. I had 155k on my 99 and ran a 125 shot on it and all the bolt ons for thousands and thousands of miles. Look at auto trannies, you can have one rebuilt with stock parts and it will last 1/4 as long as a new OEM trans. Rebuilt engines go along the same principle, of course unless a reputable builder is building the trans or the engine. A stock 6.0 can take 500 RWHP all day for many many miles provided its tuned right. Rebuilding an engine never turns out to be as easy or cheap as 99% of us plan on it being. If you are building a 5.7, you might as well put good rods and pistons in it. Thats damn near the cost of a 6.0 right there. Just throwing that out there...

joeyc125

iTrader: (7)

OR......get an lq4 and put your 862's on there and be at your compression, bigger displacement, and lots cheaper. I can find lq4's around here for 8-900 with under 80k.

00_Hotrod

Kimm Barr Racing Engines in Dallas Built the heads, LS1 VALVES & MAJOR PORT & POLISH, MILLED 30K, I can't tell u the flow # off the top of my head but at the time talking w/ Barr and flow # comparisons they will out flow a stock 317 6.0 head, as for Engines I have built 100's of Hi po motors in my time and know what it takes to do the job And will build this one my self like i have done everything thus far with out a problem But if I'm going to spend money i want to put it somewhere i get the best gain and I think w/ what i have put on a 5.7 w/ the compression increase & flow increase it will out preform a stock headed (317) 6.0...U do know thier is a power increase w/ compression increase & flow increase....

turbosilvi

from what you are saying... and how much time and money youve already put in your 5.7, i would stick with that and put your parts on that. and if youve got friends with shops that owe you, i would get as much out of them as possible. throw an intake on the 5.7 and a nice cam, exhaust upgrades are a definite, and have it tuned. like previously said, if your gonna be spraying more than a 125 shot frequently, i would think about investing in some bottom end upgrades.

00_Hotrod

I'm running a 5.3 right now but planning on a 5.7 and do all the tuning myself w/ DST, I have not had this thing dynoed yet but so far best 1/4 ET is 13.46@103, doing research on the net and trying to get a guessement on hp ET calculator shows around 475hp at flywheel, this is my daily driver but i would like to get around 500 to 550, I dont want to get to crazy with it...

joeyc125

iTrader: (7)

Well if you have built 100's of hi-po engines, then why are you asking strangers on the internet? you should know exacly what the difference in displacement and compression will do...

1Bear

iTrader: (1)

It sounds to me that you have already made up your mind. But as has already been mentioned, if you have a good set heads, why not use them on a 6.0L? It sounds like you’re planning on reusing your existing 5.3L for a build, but unless you’re just trying to get out a cheaply as possible “which is understandable”, why not pick up another short block to build and then throw your heads on it and go? That way you don’t have as much down time. I don’t know your situation, but for me down time is important. If you do pick up another short block to build, then a 6.0L would be a good choice as they are not that much more expensive than a 5.3L and you could take your time with it. There is nothing wrong with building an iron 5.7L at all and they run well, but one item most folks overlook and one the reasons LS1’s rev so well is the slightly lighter rotating assembly “of course they had a little more aggressive cam as well”. The truck cranks are solid, while the LS1’s have gun drilled mains making them lighter.

00_Hotrod

Did you get a chance to read the first page of the thread. I'm not asking u what compression will do I'm telling u, Well everybody talks so highly of the 6.0 and i was just asking a question and I guess u think u know it all, I'm just trying to find out why everyone thinks the 6.0 is the greatest thing ever to hit the streets.....

mcfarlnd

iTrader: (15)

most people just get the 6.0 and slap it in with out a rebuild but, i honestly wouldn't do it and it doesnt sound like you would either. i have personally done a 5.7 iron block from the ground up and the money added up rather quickly, but we used nice stuff including gm rings, arp bolts and studs, we had the rotating assembly balanced, 228/228 588 588 cam, dual springs and some port matched ls1 heads with just a valve job, etc. etc..... it put down 376hp and it still has room in the tune. also, if it had some good heads and something other than the stock truck intake it would make quite a difference.