L98 Block questions

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Feb 3, 2012 | 06:14 PM

JohnnyFive

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L98 Block questions

I was wondering what hp capability my stock 1989 L98 block has. Assuming splayed 4 bolt mains and maybe a girdle?

Feb 3, 2012 | 06:59 PM

rklessdriver

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From: Dale City VA

Quote:

Originally Posted by JohnnyFive

I was wondering what hp capability my stock 1989 L98 block has. Assuming splayed 4 bolt mains and maybe a girdle?

There are way too many variables to give you a real number for what some random L98 block will support.

However I will tell you that a number of people have turbo'd stock blocks well over 1000hp without failure.

In the late 1980's thru the early 1990's we were making over 600HP normally aspriated with stock 4 bolt main SBC's. Those engines were used in oval track cars, were raced an entire season before tear down and I can not remember losing one due to a block failure. OF course we sonic tested the cyl walls and before that we always selected the best of the pile - By looking (at the cam thrust surface) for the least core shift.

A good L98 block, with good machine work and splayed caps would most likely live beyond any amount of HP you could make in a street car.

BTW splayed caps are worth the work and $$$$. A Main Girdle is a useless hunk of metal that serves as a good basket to keep your (blown up) parts in.
Will

Feb 4, 2012 | 09:16 AM

BLOCKMAN

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From: NORTHEAST

Sonic test forst and don't go by core shift as I have block that show alot of core shift but sonic test fine, I have alot of block with no core shift but have faled a sonic test and most have one cylinder that fails which makes the block junk for a performance build

If you go to splayed caps use a flat bottom cap with a 10 degree outter bolt ange as it will not get you into the water jacket.

Since Program Engineering seems to be hard to get caps from this company here has a very nice splayed caps for 160.00 and made in the USA.

http://www.cipcoindustries.com/

Feb 4, 2012 | 09:34 AM

ddahlgren

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From: Mystic CT

All the Calloway cars had splayed caps from Programm.. I set up the tooling for it along with line bore line hone etc.. None of the bolts hit water when drilling. If memory seves me right they made over 525 ft lbs and the number 537 comes to mind though may be wrong on that. At 7500 rpm that is 750 hp at the crank.

Feb 4, 2012 | 10:27 AM

BLOCKMAN

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From: NORTHEAST

Quote:

Originally Posted by ddahlgren

I am a W-D with Program but never can get anything out of them now and the caps that CIPCO makes are identicle to the Program caps

Feb 4, 2012 | 10:36 AM

ddahlgren

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From: Mystic CT

Quote:

Originally Posted by BLOCKMAN

I am a W-D with Program but never can get anything out of them now and the caps that CIPCO makes are identicle to the Program caps

I am sure the caps you can get and are happy with are great. I was just shooting out a baseline to see if it is what they guy was looking for. Is Progamm just running flat out to keep pro racers supplied? I know in this economy running at 100% capibility with back orders is a lot more secure position to be inthan buying more machinery and taking a chance the orders do not keep coming in to suppurt the new expenses in machinery and employees to run them or even worse to have to relocate if out of space.

Feb 4, 2012 | 11:41 AM

BLOCKMAN

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From: NORTHEAST

Quote:

Originally Posted by ddahlgren

Since the new dart blocks have come out there is really no market for caps any more, In fact the trade shows I have been to the past years Kenny the owner of Program has not even had a booth there.

When I did my W-D buy in I was told I would never have to stock his caps he would have them on the shelf. Now that has changed!!!

Nobody can get there caps any more Callies, CV Products, Oliver as I have calls from some of these companies asking if I have product.

Feb 4, 2012 | 12:06 PM

1991Z07

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From: Austin Texas

Quote:

Originally Posted by JohnnyFive

I was wondering what hp capability my stock 1989 L98 block has. Assuming splayed 4 bolt mains and maybe a girdle?

As others have said...too many variables.

What cubic inches you aiming for? 355, 383, 396?

Going with Tuned-port? With good heads and a great flowing Tuned Port you could see 430-450HP naturally aspirated.

Thinking about a SuperRam? Those numbers go up about 10%-15%

Thinking about a MiniRam or StealthRam? The numbers increase dramatically.

Add a hairdryer or Vortec and you'll see lots more.

You need to be more specific on what you want to do before anyone can give you a fair estimate.

And reckless is 100% spot on...a girdle will do nothing for you unless you plan to spin it to 9k RPM and hold it there for hours. Just more weight to carry around...

P.S. My 355 with Accel base, TPIS runners, 58MM TB, CNC'd heads with 4-bolt splayed caps made 430 FWHP and 535 lb/ft

So far, it think it is the highest benchmark I've seen on this forum for a stock-style TPI. Totally stealthy & ridiculously bad-a$$ when you can spin tires in 1st & 2nd just by flexing the right foot.

Last edited by 1991Z07; Feb 4, 2012 at 12:12 PM.