2.8 top end swap

[Superdave]

First, yes I saw that someone recently bumped up a thread about swapping a 3400 on to a 2.8, and yes I went through all 14 pages of it. Seeing as that didn't really get anywhere I figured I'd start my own thread.

What I have:

I currently have an 88 GP 2.8/282 combo with tgp parts on it. I ran about 5-6000 mile on that this summer, and I figured it was time for more. Seeing as I don't drive the GP in the winter, I figured it would be a good time to add some parts.

I also just bought a 98 3400 with a ton of miles on it, ~182k if i recall. Full of nasty emulsified oil. Guess the previous owner had some good LIM gaskets on it....NOT

I've torn it down and pulled the heads off so far.

I plan on running LS6 springs with the Comp retainers and locks.

I'd stay away from the LS6 springs, from what i've seen in a recent engine build they are junk. We are using them on a 3400 with a .506 lift cam.. he's broken 2 of them and they are well away from coil bind. The Comp 26915 springs are MUCH better and they fit with all stock hardware and seals.

What I need:

1.) Right now, I'm planning on the GMPP Crane 260. $160 w/lifters is tough to beat. Can anyone suggest a better turbo cam for a similar price???

that's a decent choice, here is a list of other flat tappet cams: http://members.shaw.ca/betterthanyou...haft_guide.htm

2.) What should I check the heads for? I was planning on checking valve guides and a 3 angle valve job to clean up, and probably just have the mating surface cleaned up too, not milled or anything, just cleaned up. Is this logical?

Yep, replace the valve seals as well when you upgrade the springs.

7.) A good excuse to tell my girlfriend why I NEED to do this.

She'll never understand, just hint around it for a few days and then drop the bomb after some really wild sex.. LOL

thats cool man-anything special done to the bottom end? and how much boost were you running-also ive heard 3400 heads wont work because the combustion chambers are too big.

no_doz, for someone who asks so many questions you really shouldn't be giving out engine building advice. No offence but you are spreading incorrect information.

3400 heads work on a 2.8 just fine

[ghrarhg]

The bottom end is stock, only upgraded the oil pump. I've been running up to 10psi, but normally closer to 7-8. I'm using the TGP Garrett T25 turbo.

[no_doz]

thats cool man-anything special done to the bottom end? and how much boost were you running-also ive heard 3400 heads wont work because the combustion chambers are too big.

[ghrarhg]

Hey Jon, I live on the East side of Cleveland in Mentor, but I work in Columbia Station (a little closer). It looks like you're over a hundred miles from me. Yeah, I ran all last summer with the turbo. I'd say between 5-6000 miles on it. I put 1000 miles on it the first week I had it running. Much improved over the plain 2.8.

Does anyone know the difference between the felpro gasket kits HS9957pt1 and HST9957pt1? Seems like there is a large price difference.

Also, do either of these kits come with the metal LIM gaskets?

Last, is there any way to run a vacuum EGR on a 3400 or 3500 UIM? I'd like to keep my EGR if possible.

Thanks,
Jon

[no_doz]

lol my name is Jon, too!

[no_doz]

first off-has this 2.8 been running with a turbo? and as for your questions:

2.) What should I check the heads for? I was planning on checking valve guides and a 3 angle valve job to clean up, and probably just have the mating surface cleaned up too, not milled or anything, just cleaned up. Is this logical? --very logical, as long as your guides are good, your valves are sealing, nothing appears broken or cracked, & the mating surface of the head is for sure as nice as it needs to be, you should be fine.

3.) Can anyone recommend a decent machine shop in NE ohio to do the head work?
-depends on the part of ohio that you are in, lmk what city

7.) A good excuse to tell my girlfriend why I NEED to do this.
-tell her "putting the new cylinder heads/intake manifold on my car will increase efficiency & flow as well as improve the venturi & swirl, leading to better combustion & atomization, leading to increased power, mileage, and reliability" thats technically not outright lying to her, and if she DOES have any questions about that statement, either shes nosey as hell or might be one of the 35 girls on the planet that actually care about cars. p.s. that part about the venturi/swirl is just crap i threw in there because i HIGHLY doubt she knows what that means.

i live in central ohio-right over by mount vernon, how close to me are you?

[ghrarhg]

What would be the best route for rockers. The 3400 rockers that are on there are pretty high mileage, should I assume they're junk?

If so, does anyone have low mileage replacements? Basically it's stock or crane gold race rockers right?

[montess408]

you should maybe check on the comp valve springs as they do not need any mods to work . and you will need some custom push rods for this hybrid motor .get a new timing chain.and check the heads for crack's and leaks and you should be good to go

[ghrarhg]

First, yes I saw that someone recently bumped up a thread about swapping a 3400 on to a 2.8, and yes I went through all 14 pages of it. Seeing as that didn't really get anywhere I figured I'd start my own thread.

What I have:

I currently have an 88 GP 2.8/282 combo with tgp parts on it. I ran about 5-6000 mile on that this summer, and I figured it was time for more. Seeing as I don't drive the GP in the winter, I figured it would be a good time to add some parts.

I also just bought a 98 3400 with a ton of miles on it, ~182k if i recall. Full of nasty emulsified oil. Guess the previous owner had some good LIM gaskets on it....NOT

I've torn it down and pulled the heads off so far.

I plan on running LS6 springs with the Comp retainers and locks.

What I need:

1.) Right now, I'm planning on the GMPP Crane 260. $160 w/lifters is tough to beat. Can anyone suggest a better turbo cam for a similar price???

2.) What should I check the heads for? I was planning on checking valve guides and a 3 angle valve job to clean up, and probably just have the mating surface cleaned up too, not milled or anything, just cleaned up. Is this logical?

3.) Can anyone recommend a decent machine shop in NE ohio to do the head work?

4.) 3100 GP throttle cable

5.) Water Neck from thermostat housing in LIM, JY swiped mine.

6.) Coolant bypass pipe, goes to TB and heater core, JY sawzall'ed mine. I'm not 100% on this one yet, seeing as i have to T into it for my turbo coolant return. I've heard that i need a new one, and the old one can't be carried over.

7.) A good excuse to tell my girlfriend why I NEED to do this.


I know I don't have everything covered right now, but I just want to make sure the ball is rolling in the right direction. Springs, retainers, locks etc can be ordered or picked up, I work close enough to Summit Racing that the LS6 stuff can be gotten in a day. Just want to make sure when I take the heads in I've thought of anything.

Thanks for your help in advance. I'll post pics eventually if anyone cares.

Jon