brucer

my car is a 98 trans am with 88k miles on it, ls1 has the #4 rod bearing wiped out....

went and picked up a high mileage 2003 lq4, like 200k miles.. pulled it apart and it still has crosshatching in the cylinders, block is clean for the mileage evidently guy kept his oil changed, cam was in good shape all bearings looked great.


I'm planning on just reringing the lq4 and using the valve train out of the ls1 and replacing the timing chain.. might stick a small cam in it, maybe a hotcam... I'm having the heads milled .035, new seals and z06 springs.

car is just going to be a driver, I have another old hotrod that I'm building.

I'm wanting some information on the swap, the lq4 had a single cross steam pipe on it, ls1 had one that went front to back, can i use either or do i need to use the ls1 steampipe with the ls1 intake? I also have all the sensors from the ls1 that i'll swap over to the lq4 along with the oilpan and windage tray and intake, fuel rails, injectors and such....

If i go ahead and use the stock cam, if i can even use the ls1 cam in the lq4? would I be ok to run the engine on the stock computer or should I get it tuned asap.. I wouldnt mind getting it dyno tuned in the future just to get it running as good as it can.

on the 88k mile ls1 with the jacked up rod bearing, would it be worth anything selling it as is? I know the block and heads are still good.. I was thinking about selling it or just pushing it to the back of the garage and using it for something later on, maybe another streetrod project..

thanks

mikesanto70

Make sure you get info from someone who knows their **** because 98 LS1's were different from all 99' and up LS motors and the computers are different, I would call TEXAS SPEED and ask them, they are LS motor gurus and will be able to give you credible information. 1-806-698-0365 good luck
PS, cam that bitch, better valve springs, and mill the heads to get the CR up!!!
and get a good tune and it will be a strong runner!!!

Redbull87

iTrader: (3)

From experience on my own car..you can run the front and rear steam pipes on the lq4 heads.Literally everything on the ls1 can be swapped onto the lq4 and start it up on the stock ls1 tune and it will run pretty good that you wont notice anything different but it should be tuned for the bigger displacement asap.

If you are going through all the trouble..put a cam in it now,due what upgrades you can and tune it once and be done.I went from stock 00 ls1 to an 04 lq4 and added a cam and ls6 intake and the only sensor I had to change was the oil pressure unit..reused the ls1.Everything else was the same and I kept the ls1 sensors as spares.It fired right up and ran pretty good on the stock tune.Dyno tune made a world of a difference though is how it ran and got much better mileage.Good luck.

bww3588

iTrader: (49)

If your using a stock cam for whatever reason, use the cam out of your ls1. The 98-00 cams were slightly larger than the later ls1's which received the lq4 cam. So the cam profile is the same as a later ls1 cam in the 6.0. But I agree, if it's worth doing, it's worth doing right. Not twice. Get a decent cam package and you will be much happier.

Also, I don't see new bearings in your plans...do not re use the bearings. The cam bearings should be fine as you are not taking them in and out of crush, but the rod and main bearings should be replaced, esp with 200k on them.

CHADsterss

I used my ls1 steam pipe, intake, windage tray, oil pan, and water pump

Josh Hakimi

I am working on the exact same thing except I bhilt the lq4 from scratch, Texas Speed, Painless, none of those guys could answer anytjing I was asking. If your using it as a daily , 98 pcm, harness sensors will be fine.....I went with a built 4l80e , amd had to upgrade to 99+ pcm & Harness. Its a pain in the ***. Worth it, but it takes a lot of time.