Question for L98 owners

[Scooter76]

2 questions actually. Do L98 blocks have the provision for a mechanical fuel pump, & are all L98's set up for a factory hyd. roller cam? The reason that I am asking is I am planning on doing a hyd. roller shortblock for my C3. but don't want to run an electric pump. Thanks in advance!

 

[8388]

Yes to the 1st no to the second.

Roller blocks started sometime around 87.

 

[86PACER]

I AGREE.

 

[Scooter76]

Thanks for the fast replies. What I am looking at is a new L98 GM shortblock part # 12510737. I guess I can swing by Scoggin-dickey & find out about the roller cam question. Are the L98's durable enough for a mild performance, say 350-375hp. I drive my car easy most of the time (just an occasional blast) & really don't feel the need for a ZZ4 with the stronger internals & the $800 higher price tag. Any thoughts on this? Thanks

 

[rrubel]

87 was definitely the first year for the roller cam. however, it's easy to retrofit earlier ones with a lifter kit from Crane, Comp Cams, and others. I'm doing this to my 86.

And yes, it'll easily take 375 HP. Lingenfelter claims about 425 from its SuperRam/74219/heads setup, changing nothing in the block itself. You do need better springs and a bigger throttle body.

[RICHR]

 

[86PACER]

RRUBEL
IF THE L98 BOTTOM CAN HANDLE 375+HP, WHAT ABOUT THE 700R4 TRANS. AT ABOUT WHAT POINT CAN IT HOLD UP STOCK?

 

[Ken]

86PACER, I keep waiting for someone else to tell you about the upper case thing, but it looks like it's gonna have to be me that tells ya.

If you type in upper case font on the Internet, it is considered shouting and therefore considered rude. Will you please turn your CAPS key off when you post or respond to threads?

For further reading on Internet etiquette, also known as "Netiqette", see: Netiquette.

 

[86PACER]

Will do. Thanks Ken. Was not intentional

 

[Ken]

:cool

 

[8388]

RRUBEL
IF THE L98 BOTTOM CAN HANDLE 375+HP, WHAT ABOUT THE 700R4 TRANS. AT ABOUT WHAT POINT CAN IT HOLD UP STOCK?

I can tell you all about the 700r4. yes it can handle 375 hp so long as it is built right. I have one on my 570 rwhp car. The problem for me is getting it to go into 4th @ WOT with that much power. So far I can get about 4 to 6 runs before the band slips and it's fubar. If your just going to run it 1st thru 3rd and it's built right, you shouldn't have any problems. Most transmissions will handle more than what is recommened, the question is for how long, keep in mind that each application will have different results.

 

[tntcorvette]

the hyd. roller option started in late '86 then forward through '87 and on.

I have a build 700R4 that has held up through my old 355 super ram engine which made over 400 ft/lbs of torque and about 375 hp and now my 357 miniram motor which make more power than the 355.

 

[86PACER]

Thanks for the replies.

 

[hott85]

thanks 8388!

I can tell you all about the 700r4. yes it can handle 375 hp so long as it is built right. I have one on my 570 rwhp car. The problem for me is getting it to go into 4th @ WOT with that much power....

I recently had my 700r4 rebuilt, to include a shift-kit and 2500 stall converter. Numerous other mods as well..3.73 gears and it won't shift into 4th @ WOT. It's back in the shop now for them to solve the problem.. I haven't had it dyno'd, but have told the hp should be in the 400+ range.

Your post leads me to believe the problem is definitely in the transmission.

Runs fine in everyday driving, but driven very aggressively she'll bog when the rpms are maxed out in 3d gear. I hate having to lift off the gas in order to build more speed. A guaranteed way of losing a race.

 

[8388]

Re: thanks 8388!

I recently had my 700r4 rebuilt, to include a shift-kit and 2500 stall converter. Numerous other mods as well..3.73 gears and it won't shift into 4th @ WOT. It's back in the shop now for them to solve the problem.. I haven't had it dyno'd, but have told the hp should be in the 400+ range.

Your post leads me to believe the problem is definitely in the transmission.

Runs fine in everyday driving, but driven very aggressively she'll bog when the rpms are maxed out in 3d gear. I hate having to lift off the gas in order to build more speed. A guaranteed way of losing a race.

The reason your transmission is not shifting into 4th at WOT could be a combination of things.
The detent cable not adjusted properly.
Transmission pressure incorrect.
The (corvette) 4th gear valve inside the valve body has been replace with another, or the wrong spring.

4th gear OD is the weak link in the 700r4. The reason for this is because the band is applied in that gear. The band must hold the drum in order to shift into 4th, If the holding power of the band is overwelmed due to too much hp and torque, the band will slip . A couple of slips and it's over. 2nd gear is usually the first thing you'll notice slipping, since the band is applied only in 2nd and 4th gear.

 

[rrubel]

the hyd. roller option started in late '86 then forward through '87 and on.

Please cite your source. According to Mike Antonick, "Roller lifters were introduced for 1987, resulting in 240 HP, a 5 hp increase over 1986's with aluminum heads and a 10 hp over cast iron."

This is a major addition, requiring changes to the block, so it's not something they'd introduce at the end of the model year like they did with aluminum heads (which were SUPPOSED to be on all 86 Vettes anyway).

[RICHR]

 

[Mad-Mic]

i bet i'm pushing around 300 hp and 375 lbs of torque with my mods and i'm not done yet. i getting my long tube headers friday and adding my AFPR then off to the dyno for a tune on the A/F ratio to see what kind of numbers i am getting now on a basic stock L98 with some basic mods. i'm hoping 325+ hp range and 390 in torque. my tranny now still shifts as hard as it was when i first got it. after cam/heads/intake work/custom chip 400+ hp 450+ torque. well thats what i'm hoping for

truethfully the 700R4 does worry me though, especially after my mods this winter.

 

[86PACER]

Keep us updated. My 86 has the similar mods but with long tube headers already on. I dont take it to the track or dyno. This might give me an ideal of what i am pushing too.

 

[Mad-Mic]

yes i will do that

hopefully after xmas i'll have the headers on and AFPR in with a set of fresh cut back plugs then off to dyno for a bit of tuning

 

[scorp508]

the hyd. roller option started in late '86 then forward through '87 and on.

No '1987+ only. it wasn't an option once it was in place, they all had them.

You may be thinking of the aluminum heads or how all 86s are 1-piece rear main seals.

 

[tntcorvette]

Please cite your source. According to Mike Antonick, "Roller lifters were introduced for 1987, resulting in 240 HP, a 5 hp increase over 1986's with aluminum heads and a 10 hp over cast iron."

This is a major addition, requiring changes to the block, so it's not something they'd introduce at the end of the model year like they did with aluminum heads (which were SUPPOSED to be on all 86 Vettes anyway).

[RICHR]

:duh


sorry, that is aluminun heads and not the hyd. roller cam upgrade.