So im getting ready to do a top swap, any advice?

[thunder71173]

Ive got a 99 with a 3800 series II and I have recently acquired the parts to do a top swap on it. this will be my first time going deeper than an intake replacement on this motor and I was just wondering if any of you guys that have experiance doing a top swap have any advice that might save me some time and money. I know you need to replace the coupler on the supercharger with the one from zzp and since it has 9.4 or 5:1 pistons you have to run the stock pulley. I am also going to add speed daddy headers at the same time. I dont plan on making into a race car or anything I just like to have the power in a sleeper car to play around with mustangs, camaros and all the other big bad fast cars around. So if any of you guys have some helpful hints that might save me some time and $ it would be greatly appreciated!

Dave

[rmcardle3]

Hey Thunder, what is your starting point NA (or Gen3) and where will you be, when done Gen3 (or Gen5)? I don't have time to read all your other posts. Just trying to help but didn't quite know how (from your SIG, not a criticism) either way good luck with your swap. I'll be checking back here to see how it is going for you.

Edited

[blueguy]

A tune.

You'll NEED one. Other than that...just be sure you have everything situated before you dive into it. Take your time, triple check...and praying helps too LOL

[thunder71173]

I'm srarting with an L36 modding it up to a gtp from std gt. I have only done a cai new plugs and wires and a 180 t stat so far but I am going to ad a gen 3 system off of a 98 gtp to my 99 gt. I plan on adding speed daddy headers and plugs that are about two heat ranges colder because of the higher compression in my motor. I will also prob add msd 8.5 mm plug wiresand my existing cai to it.

[Bio248]

be organized. get a piece of cardboard and stick all the bolts through it so you dont lose any. keep all of them separate so you know where each goes.

USE HEAD STUDS FROM ARP.

youre getting ahead of yourself with the plugs and wires, but whatever..

[thunder71173]

so I dont need to go with a colder plug especially with the comp increase? If you dont wont it cause slight misfiring in the cylinders that would do damage to the motor in the long run? if not I will leave the stock 7mm plug wires on it and stock plugs.

[Pepino]

be organized. get a piece of cardboard and stick all the bolts through it so you dont lose any. keep all of them separate so you know where each goes...

Granted I only did LIM, but you can NEVER be to organized. I was in the same boat as you, had never touched anything besides oil/air filter changes, but just plan for more time then you need, something will cause a problem somewhere.... its just the nature of the beast. Otherwise take your time and triple check everything before turning that key.... and good luck.

Also dont know if you have a digital camera, but you can never take to many picts, granted your replacing most of the parts you are taking off.


You doing this in a garage? because the weather doesn't always cooperate...

[thunder71173]

im pretty organized and I will no doubt take my time. I would be willing to pay somone with experiance doing one of these to help me if anyone is close to southern illinois, western ky southeast mo or stlouis area.

[01gpgt01]

im pretty organized and I will no doubt take my time. I would be willing to pay somone with experiance doing one of these to help me if anyone is close to southern illinois, western ky southeast mo or stlouis area.

you need Autolight 104's

[matt5112]

once you've done this a couple of times you'll know what bolts go where.

Putting them in baggies and writing on the baggy with a sharpie is another way to keep things organized.

You wont want to use that 98 throttle body.

You want a 99+ throttle body so you can re-use your sensors. Unless of course the new TB came with sensors.

It'd just be easier for tuning purposes to have a 99+ TB though.

my only real advice is make sure the heads are in good condition before you install them, and check the harmonic balancer for cracking.

That and get a GOOD street tune. Wideband is pretty much a must IMO for any good tune.

[DaytonaGTP]

well youre on the right track by getting headers as you do this. ive heard that running a top swap with stock manis can cause a little kr but with the headers and your high compression id say youre gonna be about 30hp or more than a stock gtp when your done. since you have your heads off have you thought about having them ported or redone with bigger valves while your at it? maybe see about gettin a gen V for a good deal too? either way tune is your best friend. good luck.

[thunder71173]

once you've done this a couple of times you'll know what bolts go where.

Putting them in baggies and writing on the baggy with a sharpie is another way to keep things organized.

You wont want to use that 98 throttle body.

You want a 99+ throttle body so you can re-use your sensors. Unless of course the new TB came with sensors.

It'd just be easier for tuning purposes to have a 99+ TB though.

my only real advice is make sure the heads are in good condition before you install them, and check the harmonic balancer for cracking.

That and get a GOOD street tune. Wideband is pretty much a must IMO for any good tune.

I am using the 98 pcm with the 98 tb so th tb shouldnt be an issue right?

[01gpgt01]

I am using the 98 pcm with the 98 tb so th tb shouldnt be an issue right?

You're good to go there as long as the Maf sensor is a 98 also. 97-98's are different from 99 plus

[thunder71173]

yeah all the stuff is coming off of a 98. I had considered porting but i have heard the walls are very thin and that theres no a whole lot of room for improvement. The thing I have considered is putting 42lb injectors in place of the stock 33s after I get it running like a champ.

[matt5112]

Injectors are only useful if you want to go much past a 3.6 pulley. If not, the GTP injectors are fine.

[thunder71173]

Injectors are only useful if you want to go much past a 3.6 pulley. If not, the GTP injectors are fine.

I just had a gm mechanic tell me they might be good with the 9.5 pistons in the l36 engine

[matt5112]

You should talk to some people who tune these cars and have many hours tuning them.

http://www.prjperformance.com/

http://www.getoverkilled.ca/

3.8 Pulley + 9.4 CR = 36 # injectors aka GTP injectors.

L36 = 9.4 CR

[99prixgt]

don't forget about all the gaskets, rtv, coolant etc

when getting old gaskets and rtv off of aluminum be real careful, its easy to gouge the mating surfaces. Make sure you clean your mating surfaces on your block and heads real well. Don't forget about torque specs and sequences. Head bolts and rocker bolts are tty. Do a radiator flush before you pull apart your engine. Don't try cleaning your coolant passages with a q-tip (like i did and i dropped the q-tip in the motor ) 42#'s would be a good idea, i was just about maxing my stock ones on a 3.6 pulley.

you don't want a 97-98 t/b get a 99 style one

a tuner and laptop is a must

[99prixgt]

with the headers and your high compression id say youre gonna be about 30hp or more than a stock gtp when your done.

i highly doubt it, more like a few more if not the same as a stock gtp

[thunder71173]

well ive thrown a wrench into things guy's im going to do a complete engingine swap instead. I bought a whole motor out of a 98 with 84000 on the lower end from a site member. I am going to do headers,msd coils and wires, cai and a nice street tune any other mod advice is greatly appreciated