GTAman

iTrader: (2)

so in my hunt for a 350 engine, someone is offering me a 350 L98 out of a corvette. really interested in this engine, however, i don't know what is involved in adapting this engine to my 88 GTA. If anyone can give me some pointers about it i'll be very grateful. just can't wait to get my car back on the road again.

GTAman

iTrader: (2)

also just an FYI: the engine is from an 1987 corvette.

my apologies if this subject has been addressed but i searched and could not find anything concerning the corvette 350.

LilSki

iTrader: (1)

The only major difference that I know of is EGR and how it gets its exhaust gasses. on the iron headed 305/350 in the F-Bodies they use an exhaust crossover in the cylinder heads that goes into the intake and through EGR. That 87 Vette motor should have aluminum heads and no exhaust crossover. Instead it gets its exhaust from the passenger side exhaust manifold that connects to the back of the intake near the distributor. If you wanted to keep EGR you would have fab up something to connect your exhaust to the back of the intake.

The computer is the only other difference since you have a 305. I don't know much about factory computers but I'm sure someone will chime in.

Other than that it should be near identical and bolt right into your GTA.

PAFORM350

I was thinking of doing the same swap. Heard abot some issues with the oil pan needing to be changed. Can't verify that though.

GTAman

iTrader: (2)

thanks fellas. luckily the engine would be coming complete with everything. Plus i already have have a new oil pan so that's set. Hey lilski! how do you like that vortec in your T/A? i was thinking about those too but all the used ones have insane mileage.

vetteoz

iTrader: (13)

Vette L98 ( and LT1 ) pan with longer , shallower sump won't clear F-Body cross member
Need a regular deeper SBC pan like the ZZ4 pan shown

GTAman

iTrader: (2)

does anyone know if the TPI lower intake manifolds are the same bolt pattern? are they different between cast iron and cast aluminum heads?

Orr89RocZ

iTrader: (20)

Your intake would have the altered angle holes for the 4 center bolts. I think its a 72 deg angle compared to 90 deg for the other holes. The vette intake should have all 90 deg bolt holes.

So you will have to oval out the holes on the Fbody intake to fit the L98 aluminum vette heads. Not a big deal to do. Or just run the vette intake since its likely already setup for the EGR off the header.

other than that, there should be no difference in performance.

GTAman

iTrader: (2)

thanks! now what about exhaust? this engine has the EGR tap on the p/s exhaust manifold. can i use the corvette exhaust manifolds or do i have some fabrication to do?

Orr89RocZ

iTrader: (20)

you can do corvette manifolds if they fit but likely need a custom y pipe then. Could just drill, possibly tap the factory irons if they are thick enough and run a compression type fitting with copper line to the intake. Else weld on a tube in, like a left over steel brake line or fuel line or something?

Scoggin Dickey parts who sells the vortect TPI manifold sold an EGR kit that does the same thing. Not sure if they still have it but its worth a shot

BlackenedBird

iTrader: (5)

Isn't the accessory (alternator/AC/power steering, etc.) setup different & wouldn't fit?

vetteoz

iTrader: (13)

Obviously you use all the 3rd Gen parts and accessories on the new engine
as required

GTAman

iTrader: (2)

Orr, thanks for the insight! i know when i was considering a vortec engine i was on SD's site looking for things but didn't see the EGR kit. i'll have to give them a call. i might just get headers and have a shop weld the tube to the new header...

actually that brings up a new question: is the exhaust manifold bolt pattern the same between the two motors?

another question i have is about the computer. im assuming i need a 350 computer and prom?

five7kid

iTrader: (14)

Yes

Not completely necessary. The '88 TPI system is MAF, which isn't as sensitive to displacement changes. Of course, a 350 PROM tune would help it run better.

The 305 and 350 computers were the same thing. Only the PROM changed.

vetteoz

iTrader: (13)

Yes

NO
Just a stock 350 MAF memcal (chip) or a custom 350 tune in your existing TPI computer
Also need a 350 (MAF) knock sensor if the engine does not come with one.
Your 305 KS is different and won't work with the new 350 tune

GTAman

iTrader: (2)

great! i was planning a 350 swap anyways. i have the 350 knock sensor. concerning the memcal, if i buy one can i put it in my 305 computer? also, i am converting to manual trans. how will this be affected?

vetteoz

iTrader: (13)

As noted above , the ECMs are the same , only the tune on the memcal changes

Nothing
A auto tune has settings for convertor lockup (TCC ) so a auto tune will work on a manual
but a man tune not on a auto ( engine will run fine ; just nothing to operate the TCC )

dwinhofer

I did a L98 out of a 1989 corvette into a 1985 IROC with the 305 tpi. I used the oil pan from the 305 and I blocked off the egr and removed the air pump and plugged the holes in the stock exhaust manifolds. I put a 1985 corvette 350 prom in the computer and it ran fine until I decided to add a cam. Now it seems like it wants to overheat. I don't think the 1987 corvette came with aluminum heads so everything should fit.

GTAman

iTrader: (2)

hey everyone thanks for all the info! Just as an update: the motor is in and trans will be going in today! Here's what happened:

Definitely had to change out the oil pan. That was obvious. I ALSO had to change out the oil pump pick up because it was too long and take off the windage tray.

I put poly mounts in the car so mounting the engine on day 1 was a PITA. It would have went much easier if i had had ladyslipper pry bars that night. i picked up a set yesterday to get them through the rest of the way and the bolts were through in no time.

put on the flywheel, clutch and bellhousing as well yesterday. i'm not very happy as too how much flywheel is exposed because i don't have an inspection cover. apparently they are very rare to find. was thinking about making one. anyone have schematics?

on the top side, i was going to swap injectors and FPR from the vette rail to my old rail because of the cold start valve but i just realized that the engine is from a 1990 vette and doesn't have the hole in the manifold. Off the bat i'm thinking of getting a custom tune and deleting EGR, cold start injector, and AIR. If there's any other ways around this let me know.

back to work!

GTAman

iTrader: (2)

Also, what's are good headers for my GTA? gotta start thinking about it since it's almost go time.

five7kid

iTrader: (14)

Corvettes got aluminum heads starting mid-1986 model year.

five7kid

iTrader: (14)

Hooker 2055HKR are bolt-ins.

Orr89RocZ

iTrader: (20)

If you get a custom tune, might as well burn the chip to have the same bin file as the manual trans L98 vettes. I forget the coding for that specific bin but I can ask my corvette bud from another forum, whom I helped tune his stroker TPI setup. Its like the ARAP bin but for manual trans. I dont think i have a copy of it anymore

GTAman

iTrader: (2)

five7kid: Thanks for the recommendation, man!

Orr89RocZ: yeah i have no clue whatsoever about PROM burning so i was going to pay for a prom to be burned. definitely need one since i need to delete the 9th injector and, by the looks of things, Scoggin dicky does not sell the EGR adapter kit anymore. It's ok since i'm registering the car as historic so i don't have to worry about inspection.

GTAman

iTrader: (2)

who's got a recommendation for a person/place to get a custom prom burned? D-day is coming up soon and i gotta be ready.

GTAman

iTrader: (2)

hey guys! the swap is moving along fine. question: i know i already asked what's a good pair of headers, but i need to revise that. What's a good pair of headers that DON'T have the AIR stuff on it and might work with stock Y-pipe? I have decided to not run EGR and AIR, and because the AIR equipped headers are too expensive.

vetteoz

iTrader: (13)

Check out the listings for other 3rd Gen Camaro headers
http://www.summitracing.com/search/P.../?Ns=Price|Asc

Just make sure they fit Chevy angle plug heads like these 2 do
http://www.summitracing.com/parts/HE...RO&prefilter=1
http://www.summitracing.com/parts/HE...RO&prefilter=1

GTAman

iTrader: (2)

thanks, vetteoz! you've given me great options. i did some research before and i thought hooker 2460s were my only route. those hedman 68470s look good too! i'm trying to determine if i need a new y-pipe with those or not.

five7kid

iTrader: (14)

The cost of non-A.I.R. header plus what you'll pay at a shop to get any header w/o A.I.R. hooked up to the exhaust, will be more than what the 2055HKR's cost.

5spd-iroc

not positive on the hedmans but most headers require their brands y pipe

LilSki

iTrader: (1)

Headman 68470s fit great in my car but be aware they do not have a 02 bug on them. I had to add one to mine. They also require their y-pipe unless you fab up your own. This is a shot of the y-pipe from under my car.

five7kid

iTrader: (14)

And, the 2055HKR Y-pipe is the only one that is 3" after the "Y".

GTAman

iTrader: (2)

did you have any clearance issues on the passenger side. i'm fitting mine now. the driver's side fits great, but the passenger side is hitting the frame i think.

here's a non-header related question concerning something i just ran into: on the intake manifold, right next to the hole where the egr exhaust hose connects, there's a 45* brass fitting. what is it and what does it do? and can i plug it up?

Tuned Performance

iTrader: (92)

use a pipe plug and plug it. it was a coolant vent that corvettes used. I think it 1/8 npt.

GTAman

iTrader: (2)

you are correct, sir! all plugged up. installed water pump, fuel rail, deleted cold start valve, re-shimmed mini starter, dizzy installed, and fiddled around with passenger side header to see why it's not hooking up.

ok, first thing tomorrow i'm going to check out my ECM and prom before brian strangles me and can get my PROM tuned! lol

also gotta get an EGR delete kit. any recommended brands let me know.

Tuned Performance

iTrader: (92)

I have ones that are steel and zinc coated for the egr. but the vette manifold needs the small plate as well. The have a offer feature.

http://www.ebay.com/itm/CHEVY-L98-TP...ht_1133wt_1063

let me know, LOL

Tuned Performance

iTrader: (92)

GTAman

iTrader: (2)

yep! those are the ones i just saw on Hawks! looking real good.

Tuned Performance

iTrader: (92)

easy to make with the gasket as a template.

GTAman

iTrader: (2)

just bought them!

GTAman

iTrader: (2)

just installed those plates! VERY nice!

also got the O2 fitting installed on D/s header. cost me $25. if anyone from north NJ wants to know a great exhaust shop, go to KC's custom exhausts in Ramsey, NJ.

GTAman

iTrader: (2)

ok, ran into a problem. i put the serpentine brackets on today. Driver's side went on great, but the passenger side head is lacking one hole for the bracket on that side. i'm guessing i have to drill and tap it? do i have any other options?

also, i have discovered that the passenger side header will not go on with the coolant pipe on the frame rail (for oil cooler) installed. i am going to re-route it.

GTAman

iTrader: (2)

picture fail. womp womp.

SKELITOR117

iTrader: (3)

I didn't know the corvette L98 came with aluminium heads.

SKELITOR117

iTrader: (3)

Did you end up buying the engine?

GTAman

iTrader: (2)

yeah, they got them in mid-1986 like five7kid said. When i was on the market for an engine, vetteoz offered me his but i couldn't take him up on it because he's all the way in california. This engine i found at a junk yard a few minutes away from where i live.

Tuned Performance

iTrader: (92)

you'll need to drill and tap a hole so you can bolt the accessories on. I have used a transfer punch with the bracket bolted on to get the hole centered properly.

TTOP350

iTrader: (8)

I'm pointing to the hole you'll need to drill and tap.

GTAman

iTrader: (2)

that's what i figured. thanks, fellas, for the tips!

TTop350, how far did you drill that hole? and does it go into a water passage?

TTOP350

iTrader: (8)

Its as deep as the other holes in the head.
They really need to be a bit deeper because the F-car bolts will bottom out without 2 arp washers on a few of the bolts that go in the heads.