Mike98WS6

iTrader: (5)

My 87 GTA with the L98 pulled hard in the lower rpm's. I would just tap the gas and it would leap off the line. Once I was in 2nd going to 3rd it was all out of breath. I would say 4,500 or so. My 95 Z28 felt very strong of idle. Not quite as strong as the L98, but it pulled alot harder once it was past where the L98 left off. I was running out of breath at about 5,500. My 98 WS6 is a whole different story. It pulls strong down low, about what my L98 did. But once I rev it up it pulls like a frieght train. That was when it was stock. Now with al of my mods. It will tear your head off on acceleration. I hope this helps.

5w20

iTrader: (21)

What other difference were there than cast iron vs aluminum heads? IDK...

Frosty

iTrader: (17)

Different pistons I believe, no provisions for the EGR.

Amorget

I am pretty sure that the Vette has an EGR setup because it is a popular swap to put the Vette Alum heads on the 305 TPI motors, and I don't remeber having to change anything w/ the EGR setup.

25thAnnivZ28

My L98 pulls fairly strong down low for what it is. It routinely cuts 1.7s on DRs and 8.5s in the 1/8th with nothing more than a stock L98, bolt ons, a few suspension pieces and stock 3:23s all at 3688lbs. After the 1/8th the fun wears off real fast.

Frosty

iTrader: (17)

And you're still a tool!

Nice to see you over here Mike.

demonspeed

iTrader: (7)

I just figured it was aluminum vs iron heads. I didn't know about the EGR stuff.

technical

The Corvette L98 Al heads didn't have an EGR crossover like the iron heads, but the Corvette used an EGR setup like the early LS1's from the exhaust manifold to the intake.

I built a L98 engine with 10.5 pistons, ported Al 58cc heads and ported intake(upper and lower) twin 58mm TB, ZZ4 cam, SLP 1-3/4 headers + custom dual 3" exhaust for my '90 Camaro. That combo made power to about 5500 rpm. Was a lot of fun since I had it mated to a T-5 with 4.10's. I think the static compression was ~ 11.3:1 and man that SOB was loud with the side exit pipes.

demonspeed

iTrader: (7)

Interesting. So where is the EGR pipe located on the Corvette's manifold? Is there a provision on the Camaro TPI manifold that just isn't knocked out or what? Someone mentioned the 305 guys like the Corvette heads because of the EGR stuff. Does that mean the LB9 used the same sort of EGR setup that the Corvette L98 did?

Amorget

That is what I get for trying to remember what we had to do back in 01 w/ a friend car! What we did, from what I read that he posted back in 2001, was just left one half of the EGR hooked up and blocked the rest. No big deal really, probably why I didn't remember. The 305 likes the Vette heads because it is the same 58cc chamber as the stock 305 heads, so with a thinner head gasket we up the compresion and little and get better flowing heads then the stock stuff.

technical

The EGR pipe on the Vette's cam up from the back of the pass. side exhaust manifold into the back of the lower intake. The F-body's just used the crossover between the heads. On both manifolds the EGR sat in the middle under the plenum. The trick was to get an '86 lower manifold from a F-body without the EGR port in the back and put it on the L98 heads. The L98 heads had the traditional intake bolt pattern while the post '87 heads had the middle intake holes at a different angle. This way it looked like it had a functioning EGR system when in fact it didn't. This got past smog much easier.

demonspeed

iTrader: (7)

Very interesting stuff. Thanks for the posts.

Muffracing

Pontiac only made about 1550 (1552 I think) So there weren't many to start with. They were rated at 250 hp but really had quite a bit more. They are woth some money.

Amorget

1555, 1550 actual TTAs and 5 pilot cars, most of which are still around.

Frosty

iTrader: (17)

Thanks. That's what I meant.

Frosty

iTrader: (17)

...and L98 GTA's didn't run in the 15's unless it was beat to ****.

Amorget

.... or their drivers can only compel a LS1 to a 13.7, much less a L98 into the 14s

kukri

iTrader: (9)

I've got L98, and good thing about that motor is that u get best peformance/money ratio for street applications. Mine runs 12.1 and it was pretty cheap. Pulls down low 1-2500 and high 4000 - 7000 rpms pretty hard..
and mm the carburetor noise..
I dont know about people having 700+ rwhp on the street, that's pointless to me..i already cant keep traction in 1st and 2nd and it's prolly 350-400 rwhp
gunna dyno this sumbitch soon

the stock motors however is definetely LS1>LT1>L98, no question bout it, I've driven/had all. LS2>ls1 omfg!

bad0211secws6

iTrader: (6)

never heard of a tpi l98 that was still pulling after 4500???

kukri

iTrader: (9)

<<<<---mine does. i didnt build it either
it's not stock tpi 350, been bored over and built a lil better