347 vs 5.3

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Apr 26, 2016 | 12:15 AM

Ajq1540

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From: Florida

347 vs 5.3

Hey all, I'll start off with this. I'm 19, my dad and I try to do as much of the work as possible, I'm in college a few hours from home. On a trip home I noticed my oil pressure was less than usual, around 30-35 (42 is normal) put the clutch in to get off the highway and was watching the oil pressure gauge, started to head towards 0 and I shut it off. Got it towed to my mechanic, cold start 45 psi at idle. Did an oil change, still 45-50 at idle on a cold start, used to be north of 60. I get to the shop and hear the car run and it's making a low tone knock, not frequent enough to be top end. Took the head off and the pistons are fine, all lifters are good. Top end is fine. Car idles with no problems. Tried to answer as many questions as I can think of that might come up. Feel free to ask away.

Engine has forged mahle pistons, Callie h beams, 232/238 .620/.612 cam, and ported 243s with an ls6 intake.

Looking to do this as cost effective as possible. Here are the options the way I see it.
1. Take it to a shop, 5.3 swap and be done with it and tear into the 347 in the mean time. ($775 driving away)
Or
2. Do the work myself (with help of tech buddy) pull the 347, take oil pan off and see what the damage is, repair and install (no clue how much)

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Apr 26, 2016 | 12:17 AM

Ajq1540

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Is it worth fixing my current motor or would it make more sense to swap in the 5.3

Apr 26, 2016 | 12:34 AM

conan

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From: Back in the Burg

Was the oil drained and checked for excessive metal ? I would pull the pan and see whats going on before I made the decision to swap in a 5.3.

Apr 26, 2016 | 09:22 AM

Ajq1540

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Sadly I didn't get a chance to go through the oil. Mechanic drained it, don't think he looked at it too much.

Apr 26, 2016 | 10:15 AM

TimE

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To me, it sounds like a cost vs. time issue. If you have the time and money, I would suggest pull yours out, inspect and then decide 5.3 or repair and replace. At that point, though, it would be tough to get it to a shop if you decided you don't have the time or money it may take and need the car drive-able quickly.

Based on your choices given, if it's your daily and it needs to be a quick, inexpensive turnaround, the 5.3 "drive away", imho, would be most likely be faster(although not as fun as the 5.7).

Apr 26, 2016 | 10:21 AM

one fast zo6

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cut the oil filter open and take a look. check oil sending unit

Apr 26, 2016 | 11:54 AM

Ajq1540

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From: Florida

Time is not an issue. I'd rather not lose the pistons and rods out of the 347, that's the main reason I'm questioning swapping in the 5.3. Got a buddy that is going to go through the motor with me and help fix it. I would like to have a turbo on the car by the end of the year and want to be as smart as possible about this. I know 5.3s (maybe even a 6.0) are cheap and hold boost, but with my bottom end not being stock I'd rather boost the ls1. But then it's a question of whether or not the 347 can handle 10-12 psi.