I'm working with an 87 camaro with a 350 my dad built a few years ago and we put in this car with the factory t5 and a few add-ons like ls1 brakes, vette wheels, eibach springs, things like that. My problem is that soon this engine will go back to my dad for his 57 bel air and I have a VERY tight budget. I've found a great deal on a 99 truck 5.3 complete from oil pan to intake and accessories/brackets to harness, sensors, and ecu. Since it's so complete I believe this swap can be done cheaper than building the small block i've been saving up for and in the end still be more reliable, better mpg and all around better for everyday driving. I'm limited on time to pick up this engine so i've been up late the last couple nights researching and have lined up most parts I know i'll need:

f-body manifolds, oil pan, intake, and accessory brackets
ls swap engine mounts
ls swap throttle cable
and I know i'll need to fab a y-pipe
if there is anything else i forgot let me know

The last things i'm not sure about are the tuning and what to do about the transmission. I see there are programs and tuners that can 'tune out' things like rear o2's and the VATS system but how much do these programmers cost and are they simple enough for someone with no tuning experience to use? I'll be leaving the engine stock for now so is it 100% required to do this or will it affect how it runs if I just leave them unplugged? Also will it cause any issues using a manual trans with an ecu from an automatic truck, and what is the fix for that if it does?
My next issue is the transmission. I know from reading other posts the t5 is junk and I should throw it away because the first time I shift it there will be a fiery explosion and I will die. But...again I'm on a small budget and cant afford to buy a t56 right now. I do plan to add a t56 later when I have the funds so even though the t5 is holding up very well it is just temporary. I see there is almost 1/2" difference i need to make up at the crank flange and have found people adapting them with a taller pilot bearing with no problems. I see they use a big block bell housing and custom linkage or a universal internal slave cylinder because the biggest problem I think is the 11" clutch hits the t5 bell housing when it is bolted up. Is there a reason I could not have the 5.3 flywheel drilled and tapped to fit the t5 clutch and pressure plate I already have, and would that give enough clearance in the bell housing? Or does anybody out there make a big block bell housing that will clear the bigger ls clutch and can mount the t5 and external clutch master cylinder I have now?

P.S.- There are a lot of threads asking about adapting the t5 to a ls engine, but they are so cluttered with posts about how it shouldn't be done and how bad an idea is, that you can't find any real information so please everybody remember...I'm looking for answers not opinions. Thanks

 

You can get the ECM reflashed to remove the vats, rear o2's etc. you can find all the necessary pin outs and instructions to build a stand alone harness here or LT1swap.com is great help. Reflashing varies depending on what kinda tune you want/need. The t-5 can be made to fit rather easily, EVERYONE tends to shun away from this but from what I gathered a 231 big block Chevy bell housing, ls1 flywheel with a mustang 11 inch clutch disc from I believe from 99-up. Now with the pilot bearing I personally had a machinist cut my input shaft down from 17mm-ford to 15mm-gm and used the factory ls1 pilot and I retained the factory clutch cable and linkage and it works fine. And I kept my factory driveshaft and mount. I'm running a TKO600 and QuickTime bell but pretty much same deal with t-5. I was going to use a t-5 myself but couldn't get my hands on one, came into some cash and got a great deal so it can be done easier than they tend to make it. Just my 2 cents good luck!

 

I got ahead of myself oops, you have a GM setup, but same 10 splined in put shaft I believe and the external slave should still work, and no need to machine input shaft as its already proper size, but I do believe it's shorter than a ford by 1/2 maybe.

 

Thanks for the info I have found that I can use a Ls7 pilot bearing and the big block 621 bellhousing to clear the clutch but still not sure if it will make up for the shorter input shaft. Is there any difference in the clutch and flywheel for a ls1 and the 5.3? I also found a site selling hydraulic slave cylinder retrofit kits for these same bellhousings that would make my install easier since I could use my factory master cylinder.

 

I've only dealt or seen for that matter 5.3L with 4at, but LS flywheel and plate fit/work just fine I've found. I kinda wish I had have bought the 621 bell sorry gave wrong number before but the QuickTime bell was pricey!