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'90 K5 - Project Betty - LS3 Swap for a DD/Offroad/Utility Build
- Thread starter cliles
- Start date
K5 Jess
1/2 ton status
and a cold beer! thats sexy 
502 Ram Jet vs LS#/X Need Advice Please
It has been quite a while since I have updated my CK5 build. I renovated a foreclosure which really got in the way of my 454-496 stroker engine build, but now I am back at trying to upgrade my 90 K5.
After doing a lot of engine simulating and cost estimating, I decide it made more sense (both from a time and $ standpoint) for me to just buy the 502 ram jet crate engine then having the 454 that I pulled stroked & bored to a 496, piecing together the EFI setup or buying a "plug & play" kit from Holley, Fast, etc. I know those with tuning skills will probably disagree, but I do not currently have that expertise and I am trying to get the project done by mid-summer.
Just when I was about to add the 502 RJ to my cart, and piece together the accessories I read that for the same-ish $ amount you could build or buy a LS3 turnkey crate which would give you similar to more power, be lighter, and more fuel efficient (everybody agreed LS7 is better option but to pricey for my budget, and LS3 seem to stand-out as the best of the other LS options).
However, after trying to research this for several hours, I only came up with peoples opinions without much back up. Most of the threads were LS-something vs BBC, and the BBC option was always carb'd. That to me seems like a clear apples and oranges comparison. Especially when talking about drive-ability and fuel economy.
So my questions are...
1. I feel like I would be very happy with the RJ's hp/tq curves, is it reasonable that I could get an LS3 turnkey that has a similar tq/hp distribution (that high & flat torque that the 502 has and a BBC is known for).
2. Would there really be any savings as for as MPG's? I know that gas mileage is not something that most of us are concerned about, but it seems foolish to disregard since I want to do a lot of road driving and we are talking about spending similar dollars, so why not get something that is more efficient.
3. Outside of the engines contribution to MPG's, what about the weight difference. I could never find the approximate weight of either engines, just that the LS3 was aluminum, and therefore should be lighter.
4. Reliability - a lot of people commented that the LS3 was more reliable (once again this was often compared to a carb'd BBC of any kind). Thoughts? People also commented that GM builds crap engines and the RJ is just that. All of those people were building GM vehicles, so I did note the hypocrisy, but is there anything to it? Would a RJ or LS3 built by a third party shop be inherently better than a GM built option?
5. Compatibility - Would the LS3 be more or less compatible with my 4L60E setup that I am currently running?
Anything else I should know/do?
Thanks,
Chris Liles
It has been quite a while since I have updated my CK5 build. I renovated a foreclosure which really got in the way of my 454-496 stroker engine build, but now I am back at trying to upgrade my 90 K5.
After doing a lot of engine simulating and cost estimating, I decide it made more sense (both from a time and $ standpoint) for me to just buy the 502 ram jet crate engine then having the 454 that I pulled stroked & bored to a 496, piecing together the EFI setup or buying a "plug & play" kit from Holley, Fast, etc. I know those with tuning skills will probably disagree, but I do not currently have that expertise and I am trying to get the project done by mid-summer.
Just when I was about to add the 502 RJ to my cart, and piece together the accessories I read that for the same-ish $ amount you could build or buy a LS3 turnkey crate which would give you similar to more power, be lighter, and more fuel efficient (everybody agreed LS7 is better option but to pricey for my budget, and LS3 seem to stand-out as the best of the other LS options).
However, after trying to research this for several hours, I only came up with peoples opinions without much back up. Most of the threads were LS-something vs BBC, and the BBC option was always carb'd. That to me seems like a clear apples and oranges comparison. Especially when talking about drive-ability and fuel economy.
So my questions are...
1. I feel like I would be very happy with the RJ's hp/tq curves, is it reasonable that I could get an LS3 turnkey that has a similar tq/hp distribution (that high & flat torque that the 502 has and a BBC is known for).
2. Would there really be any savings as for as MPG's? I know that gas mileage is not something that most of us are concerned about, but it seems foolish to disregard since I want to do a lot of road driving and we are talking about spending similar dollars, so why not get something that is more efficient.
3. Outside of the engines contribution to MPG's, what about the weight difference. I could never find the approximate weight of either engines, just that the LS3 was aluminum, and therefore should be lighter.
4. Reliability - a lot of people commented that the LS3 was more reliable (once again this was often compared to a carb'd BBC of any kind). Thoughts? People also commented that GM builds crap engines and the RJ is just that. All of those people were building GM vehicles, so I did note the hypocrisy, but is there anything to it? Would a RJ or LS3 built by a third party shop be inherently better than a GM built option?
5. Compatibility - Would the LS3 be more or less compatible with my 4L60E setup that I am currently running?
Anything else I should know/do?
Thanks,
Chris Liles
K5 Jess
1/2 ton status
what kinda beer is that?
Engine, Tranny, & Tcase are out. LS3 should be here tomorrow. 4L80E will be built in a week or two, NP241 will have its input gear and SYE installed by then to.
Thanks for all the advice. Now the real adventure begins, I am sure I will have plenty of questions if yall have the time.
Thanks for all the advice. Now the real adventure begins, I am sure I will have plenty of questions if yall have the time.
subscribed for the LS3 
LS3 Swap
Are you qualifying your subscription bc the rest of the build is too ****ty to follow?
jk, I really have not been giving the k5 the attention that it needed bc this renovation has been kicking my ass, plus a couple of big promotions landed me more hours and responsibility.
I think in the next 6-8 months I will be doing somethings that will be worth following. I think I am taking my blazer in a pretty different direction most of the other users that are building for shear offroad ability.
subscribed for the LS3
Are you qualifying your subscription bc the rest of the build is too ****ty to follow?
jk, I really have not been giving the k5 the attention that it needed bc this renovation has been kicking my ass, plus a couple of big promotions landed me more hours and responsibility.
I think in the next 6-8 months I will be doing somethings that will be worth following. I think I am taking my blazer in a pretty different direction most of the other users that are building for shear offroad ability.
I was just following the link you left in the RJ502 vs LS3 thread.
I like what you are doing with your K5 and I have built my K10 in a similar fassion. I get tired of seeing threads that involve cutting away 1/2 the body and the remainder is so beat to hell that you hardly recognize it as a K5 anymore. Keep up the good work, and I can't wait to see the LS3.
Like I mentioned, but I will reiterate, I was just kidding. I appreciate your subscribing. It really helps to have experienced people checking in once in a while. You are probably 1 of 8 threads that I frequently peruse for references.
So its tomorrow, where's the LS3? 
It got delayed till friday because even though I paid for shipping to the door, FEDEX had to charge me an extra 90 bucks and bring a truck with a lift out.
I got it now, I was going to post the video of its arrival, but this site will not let me load videos. I have never posted to youtube, so ill have to figure that out.
Got the 350/700R4 on the ground, the 454 off the stand, and I'll try to get the LS3 out of the crate and on the stand after lunch.
I got it now, I was going to post the video of its arrival, but this site will not let me load videos. I have never posted to youtube, so ill have to figure that out.
Got the 350/700R4 on the ground, the 454 off the stand, and I'll try to get the LS3 out of the crate and on the stand after lunch.
LS3 still crated
Block didnt have any brackets for a chain/hook. Did not want to poorboy it with a bolt through the chain and risk scratching something up. will rig something up today, plus i need longer bolts
Block didnt have any brackets for a chain/hook. Did not want to poorboy it with a bolt through the chain and risk scratching something up. will rig something up today, plus i need longer bolts
427 out of crate and on stand
Well it was like tetris getting all of the engines moved around. I really need to build a gantry style hoist. The engine hoist legs are too long/not wide enough to pick damn near anything else, and its a beating to get things on and off the stand because the stands legs are too wide to fit between the hoist.
Well it was like tetris getting all of the engines moved around. I really need to build a gantry style hoist. The engine hoist legs are too long/not wide enough to pick damn near anything else, and its a beating to get things on and off the stand because the stands legs are too wide to fit between the hoist.
Sexy
