Hey I have  an 1985 Vette that needs a rebuild. Should I replace the motor or use the L-98. Or is there any low budget mods that I can do to make some h.p? Oh and why did G.M make the L-98 as a 2 bolt main?  

     Hey there Nick6137, If you keep your engine then I would susggest these few budget-mods to help increase your power. I am using all of these exept for #3, but I will be ordering a set of those shortly.

1. Tornado fuel saver- extra 10 horsepower

2. 160 degree thermostat- 10 or more horses at a cooler runing 160 degrees which should keep you from overheating and blowing your engine. Look up Hypertech on the web and Check out their 160 degree power stats.

3. a set of March underdrive Pullies for your serpentine belt- up to 15 extra horses are achieved by slowing down everything connected to your pullie system.

4. I will soon be replacing my box type filter that has a hose connecting the filter box to the throttle body with the traditional pan style fiter that has the round open air filter in it. This will not only allow for more room under the hood of my truck, but will increase my horsepower since I will bypass that lousy hose and just have direct airflow into my engine. I have a 1996 S-10 SS with the 4.3 OHV V-6 by the way.

5. A K&N air filter- extra 10-11 horses

6. K&N Oil filters for every oil change- better oil fitration which should give ya' maybee an extra couple horses besides keeping your engine running better and extending it's life.  

I hope this helps ya'. If so please reply.

The L98 is a great engine.  I have one in my 85 Vette. (OK my wife's 85 Vette)  All stock and at 150,000 miles, the car would run very consistant low 14's.  I'm rebuilding it now for more power  but I'm not going low budget.  (AFR heads, TPIS lower intake and large tube runners)  Also I had to get a new block because the original had 4 cracks in it.  It never leaked water but I did not want to take any chances.  I bought a 4 bolt main roller block from a truck.  The best thing about the L98 is the low and midrange torque.  You just can't beat it for a street car.

I've seen these cars run mid to low 12's with headers, exhaust, a mild cam, ported stock heads, ported MAF, and the TPIS intake.  One magazine out there has a full weight Camaro with stock converter and stock gears that ran 12.50's.  They replaced the TPI intake with the Mini Ram and got it to run 12.00.  (with loss of lowend torque though)They still have the stock computer tuning and stock heads.

I don't know why they made the engine a 2 bolt main.  I guess it would be because a 2 bolt is more than strong enough, they probably saved a little money.

A few free mods - increase your fuel pressure, remove the screens on your MAF (529cfm stock to 711 cfm without screens),  and port the plenum. TPIS Insider Hints book gives a lot of information and ideas plus some dyno tests on various combinations.  They even have info on their '85 vette.  The book is kind of old but the info is still good.

The L-98 didn't need 4 bolts at its power level. HD trucks have 4 bolt blocks anticipating that they'll be working for a living and therefore be operated at high power settings most of the time. While the absolute power of a truck may not be as much as the 'vette. The 'vette, unless racing, is never working all that hard. It probably doesn't use much more than 20-30 hp to get down the freeway at 60-70mph. 

The Chevy SBC bottom end is pretty durable, one usually doesn't need to worry about maincap creep untill you're pumping 450 or more hp through the engine and using it (the horespower) regularly. If your going to build an engine in this area (which with your 85 is tough to do and still be SMOG legal) you can always opt for a four bolt conversion kit like Milodon's, or pick up a truck block. Be forewarned that unless you're getting a new block from GMPP, truck blocks having 2 or 4 bolt mains cannot be identified by casting number. If you're getting a junk yard dog to rebuild, you've gotta pull the pan and count bolts.

Whether to rebuild or replace your block will hinge on how much power you can realistically get out of the engine, how you will use the engine, and what condition the block is in. In the latter case; these modern engines run real hot with 200, 210, 220 degree thermostats and the castings are thin. This is a way of saying that if you ever overheated the engine, don't be surprised to find cracks.

Bogie

And to add to everybody else,if you haven't yet,get a good set of headers(smog legal if your demographic area requires such)just to increase the engines ability to exhale!Makes a definite difference but you need to do your homework and get something designed to work in conjunction with the rest.Good Luck!