You guys have answered all my annoying questions so far.. I think I'll get at ya again.

What I am looking at right now is an L98 motor w/ 115k on it. I am proabably going to have the block bored .030 over and put in new pistons. I am keeping the stock heads and putting in a zz4 cam and valve springs. I plan to put in a 2400 converter, and possibly run a 100-150 shot of nitrous later in the summer. I need to know a few things before I commence purchasing stuff..

-Should I have any machine work done to the crank or rods?

-What pistons should I use to obtain max power on 93 octane gas (not daily driver or anything like that so..) that will work with my iron heads and with the nitrous?

-What intake and carb do you guys recommend?

-Is it hard to gap rings and install pistons? should I have the shop do it or do it myself? what about the piston pins?

-Should I stick with 1.5 ratio rockers or go to 1.6 (I'm planning to replace my stockers either way)

Anything else I should know or do, please tell me!

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1987 Formula 350, headman hedders, Accel supercoil, cap, rotor.
MAF screens removed. 160 degree stat and manual fan switch.

Best ET: 14.745@91.317mph-Stock
Best ET: 14.418@95.51 mph-Modded
Ridiculed Founder of the Traction Impaired Crew

 

Here's what I'd use: yes you should have the crank magnafluxed (or x-rayed if you can afford it) and balanced. Also have the rods checked but they should be ok. I'd just use keith black flat tops since they're cheap but with nitrous use I'm not so sure. Use 1.6 rockers and you can't go wrong with a peformer intake. I'm not a big fan of nitrous, because if you're going to spend an extra $10 every time you want to go fast, why not just use alcohol injection?? Anyway, if you use budget internals and save your dough for some heads or heavy head work on the stockers you may well pick up 100-150 all the time. Can't beat it with a stick

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Base: 89 Iroc-Z LB9 auto 2.73 posi
Exh: 3" Dynomax muffler, 3" Pipe in place of cat
Ign: GMPP 8MM wires, Accel cap&rotor, AC Plugs
Fuel: Cleaned and flow-matched injectors, afpr, !air pump&diverter valve
Sound: Clarion deck, Kicker speakers and amps
Suspension/Drivetrain: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, All synthetics, Flexlite Transmission cooler
On the way: flow tech headers, alum. driveshaft

"Deserve's got nuthin' to do with it..."

 

You're putting together about the same motor combo as I'm doing right now, except mine will be TPI. I'm rebuilding an L98 right now, and I'm going to use the ZZ4 cam and springs also. I would absolutely recommend that you get screw in rocker studs installed in your heads to deal with the high lift. As far as rocker ratio is concerned, if you decide to use 1.6, you might want to just use them on the intake side since the exhaust is already at .510 with 1.5's. You should also definitely have the crank and rods checked to see if the cranks needs to be turned or the rods reconditioned. At 115K, the crank might just need to be polished or machined .010. Depending on your budget, you ought to consider getting the crank, rods, and pistons balanced as an assembly too. Piston rings are pretty easy to install yourself if the get the pregapped ones instead of the file fit type. I always check them with a feeler gauge to make sure the gap is right though. You do this by putting them down in the cylinder bore without the piston and sliding a feeler gauge in the gap while it's in the cylinder. You have to expand them very carefully when installing them on the pistons or you can break them. They usually have a dot on them to tell you which side faces up, and make sure you stagger the gaps on each ring. You'll definitely want the machine shop to press the pistons on the rods. I'm going to use the Keith Black signature series flat tops in my buildup. According to them, they'll hold up just fine to moderate nitrous use. Actually, the ones I'm going to use have a slight dish. I'm trying to stay under 10:1 compression. They're the KB193's with a 12cc dish. Staying under 10:1 should keep you out of trouble with the octane question, especially running cast iron heads. For an intake manifold, I'd recommend either a Performer RPM or a Weiand Stealth. If you prefer more top end, go with a single plane design like the Edelbrock Torker or Weiand X-Celerator #7546. My personal preference for a carb would be a Holley. I run a 650 double pumper and the Weiand X-Celerator intake on my 69 Camaro, and I love it. If you prefer a vacuum secondary carb, I'd go with a 600 or 750 cfm Holley. My brother got a 750 Edelbrock for his car and he's kicking himself for not getting a Holley instead. I don't want to start a big war over carb preferences, just letting you know which ones I've had the most luck with! Whew, that's enough typing for now. Hope this help you out some on your choices for your buildup! P.S. Say hello to my dad for me, he lives in Beavercreek, OH.

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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."

[This message has been edited by Pat Hall (edited February 11, 2001).]

 

if you're running N2O i'd used a flat top forged piston, not a KB hyper. have the oil holes radiused in your crank and have it polished as well as magged. have a machine shop fit your pistons, unless they're floating pins, then have the shop prep the rods and check both ends and mag check them. if you're going to gap your rings buy a filer, it's way easier. use comp 1318 rocker for SA applications. i wouldn't use an edlebrock intake, or carb. buy a weiand stealth and for a carb i'd look at around 700cfm vacumn secondary holley.

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ICON Motorsports

1st & 3rd

[This message has been edited by ede (edited February 11, 2001).]

 

with flat top pistons and 1.6' on the intake will there be any clearance problems?

 

You will also need to have your valve guides machined down some. Otherwise your retainers will hit. Even with the 1.5 rockers. I'm using the zz4 and have no clearance (piston 2 valve) with either 1.5 or 1.6. Also check your pushrod guide holes(if equipped). 1.6 rockers move the pushrod closer to the rocker arm and might bind it in the guide hole.

 

you shouldn't have any piston to valve clearance problems but you should always check it to be sure ,as well as the retainer to valve guide.

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ICON Motorsports

1st & 3rd

 

how do these pistons sound?
Speedpro Powerforged pistons:
SB-Chevy: 350
Stock type piston with 4-valve reliefs and pressed pin. Compression ratios: 9.72:1 w/std. stroke & rods, 64cc head

.030, 26.99 each..