.

 

87 I think for the cars was the roller cam. The truck L03/5 motors were hydraulic flat tappet cams.

 

.

 

Actually it was 88 when all the cars got roller cams... I'm purdy sure of it..

As for eh truck engine i thought that they were LO5's

Kat

 

I thought the LO5 was the 350 TBI, not just the truck version. The compression for an LO3 (305 TBI) should be 9.3:1 (stock)according to everything I've ever read.

 

.

 

my chiltons manual and a haynes manual both say stock compression for an lo3 is 9.5:1

------------------
1991 RS LO3

RACECAR spelled backwards is RACECAR

 

.

 

Same is true for the L03. But the truck and passenger car versions of both engines are different. The cars have roller cams, trucks don't. And at least as far as the L05s go, some of the trucks have 4-bolt mains.

 

rollers started in 87.

Trucks didn't get the rollers then though.

The L05 is a 350, cars and trucks got them, the cars had a roller cam and the trucks had the flat tappet.

------------------
1989 Pontiac Firebird Formula LO3 Auto
-180 degree stat
-Hooker Cat-Back
-velcro t-top bag
-Wonder Bar from my IROC
*****Possible future mods*****
4th gen seats, fiberglass spoiler, new paint

1985 IROC-Z, TPI Auto
-Accel Super Coil
engine and tranny overhauls coming this summer


http://www.geocities.com/krt80/

 

Keith5 is right cars got roller in 87 but trucks didn't. I have an 89 4bolt main 350 from a truck, and it has flat tappet and so does my dads 93 350 truck. The truck motors have the provisions for roller cams. you need to find the spider plate and the retainers use one though. I am going to take the roller vavetrain and parts out of my LO3 and build the 350 with it. Not the lo3 cam though.

------------------
91 RS 700R4. Open Element and Ultra Flow Muffler. ET 15.86

55 Chevy on 76 4x4 frame

 

Okay, this is really confusing. Where in the hell are y'all getting these compression ratio numbers? Right now, I am looking on page 203 of my owner's manual and page 297 of my haynes manual and they both say 9.3:1 for the LO3.

 

Owners manual: L03=9.5 to 1

 

I'm still not getting this here, lol. I have a 91 Firebird and the manual says clearly 9.3:1. Do different years have different ratios?

 

.

 

I think I read somewhere that they used differnt head gaskets in 90 or 91 changing the compression but not sure though.

 

Yeah. To me, I've heard something about that too somewhere. Someone keep this at the top so we can get to the bottom of this.

 

.

 

Not all cars went to roller in 87. Maybe the Lg4, lb9, and L98 did,.. but the L69 didn't.

------------------
1998 Z28
M6/!cags
MTI lid w/k&n
Magnaflow catback

**Previous Rides**
1990 RS
1985 Berlinetta

 

.

 

I know that the '88-89 L03's had 9.5:1 and used a .018 steel shim head gasket, and I've heard that the '91-92 L03's had a thicker composite gasket. I don't know which the '90 model was. I've never seen one with the heads off from those models. Maybe someone who has removed the heads on a '90-92 could tell us. Anybody??

------------------
82 Z28 383, Ported 215cc Dart Iron Eagle Heads 72 cc Comb. Chambers, Comp custom grind Hyd roller cam, Speed Pro .250" domes, Wheeler Motorsports 4340 I beam rods, Eagle 5140 steel crank, Weiand Team G intake, Holley 830 DP, hedman headers
Trans: Turbo 350 w/ 4000 stall -- Rearend 7.5 w/ Richmond 4.10's, Auburn Minispool
Best ET:11.63 @ 113.25, w/ a 7.39 1/8 @ 93.04, and a 1.626 60'


89 RS, L03 305, Hypertech Chip,cat delete, Dynomax exhaust,K&N open element Filter,160 stat, MSD coil --Trans:700R4 Corvette Servo -- Rearend: 7.5 GM 3.42 w/ posi-lock
New Best ET: 14.91 @92.9
Bassett Racing

 

.

 

The L69 was offered in 87' and 88' in the Monte Carlo SS's and they had roller lifters for both those years.

------------------
89 Transam GTA, 350TPI, auto, 3.27 rear, dual cats, gray.
Magnaflow cat-back,
K&N open element,
Best E.T. 14.63@95mph

 

.

 

I know what you meant, I just felt like adding some more useless, unrelated information. Looks liek eventually the question was answered.

------------------
89 Transam GTA, 350TPI, auto, 3.27 rear, dual cats, gray.
Magnaflow cat-back,
K&N open element,
Best E.T. 14.63@95mph