what is the differents between this two engine 88-92 L98 and LO5 other than one is tpi and the other is tbi?

 

Everything, cam, heads, compression, pistons, intake.....

 

In short, yes, one is TPI the other is TBI.

 

 

L98=TPI
Better Heads
Better Cam
Pistons?


LO5=TBI
****ty Heads
****ty Cam
Pistons?

 

I think the pistons were dished in the LO5, and flat tops in the L98.

 

Flat tops in my L05. The cam sucks.

 

L98=
240hp, 340tq
mid 9's for compression
better heads
Decent size roller cam
Good Budget Street motor

LO5=
210hp 300tq
mid 8's for compression
smogger heads
Small flat tappet cam
Good Cheap Truck engine

 

Are you sure? Are they not pistons with a flat dish, about a .25" from the edge?

 

both blocks are roller cam correct? are the blocks the same?

 

Both are roller. Mine had flat top 4 relief pistons. But mabey cuz it was a 9c1 package, dont know if the regular L05's had them.

 

Both have roller blocks, but IIRC, the LO5 didn't have a roller cam. Could be wrong about that though.

 

If it's a 350 TBI roller from a passenger car, roller cam yes. If it's a truck, roller block yes, roller cam, no (a flat tappet just got stuffed in there).

 

Setting aside the usual TPI-TBI rants, there are at least three different LO5 engines:

a. 89-93 B platform (Caprice), police car (9C1) was TBI with 190, or 195 or 205 fwhp depending on the year (89-90, 91, 92-93 respectively) and due to slight tweaks from the factory. IIRC all used the "773" roller hyd cam, and the block was 2-bolt mains.

b. 1991-1993 non-police B platform passenger car (Caprice, Roadmaster, Olds Custom Cruiser, and in 93 the Cad D platform Fleetwood) was also TBI. These were 180 fwhp and 300 fw ftlbs. The cam in these engines was the same as the so-called "peanut" roller hyd cam used in the LO3 engine. The block was also 2-bolt main.

c. early 90s up to 1995 light C/K trucks, again also TBI. These had up to 210 fwhp in 1995, not sure about the preceding years and the hp/torque numbers; they all used a flat tappet cams (trucks didn't get rollers until 1996), but they also used a less restrictive and louder exhaust than the cars listed above so the power numbers are comparable. As a rule, I believe all GM truck-intended engines were 4-bolt.

There were two slightly different L98 engines during that era: one in the Y platform car (Corvette) and the other in the F platform car. Both were obviously TPI. The Ycar got aluminum heads using good flowing raised D-shaped exhaust ports; the Fcar got iron heads with the same basic intake and chamber shapes, but it didn't get the raised exh ports so they didn't flow as well when stock.

Both Y and F cars used the "773" cam, as mentioned above. I think there was also a different part number for the L98 cam besides the "773" number, used in earlier models of the L98 but the cam specs are essentially the same as the 773, and the full info is in one of the cam tables in either the FAQ pages or in the Tech Articles page of TGO. And IIRC for the blocks, the Y car got 4 bolt main bearing caps, while the F car got 2 bolt caps.

I don't know which LO5 or L98 you meant, but you can pick out the differences from the above. AFAIK the crate replacement engine from GM is a roller-cam passenger car version, but I doubt that it has the 773 cam because the engine isn't rated for "police use". And I don't of anyone that has pulled the cam cover and checked the pn.

I do know that several 9C1 owners have pulled their L05 cams and found the 773 pn, with one who actually miked it to verify the lobe sizes. The data agreed with the L98 773 cam info here on TGO, so it seems that GM borrowed the hotter cam from the L98 parts bin for the police LO5 engine. HTH.

 

One minor detail: Only 86-1/2-up Y platform cars got the aluminum heads.

My brother has a '93 version of that engine/vehicle. He thought it was hot stuff until he got an L98-spec rebuilt to put in it when the bearings gave out (suspect previous owner neglect). Now he really thinks it's hot stuff...

'87-up L98 and LO5 pistons both have a slight dish starting about a quarter of an inch from the outside, and valve reliefs.