I have a 91 lb9 with a 3.08 posi rear end (G80)- I'm ready to make the thing go faster (no more bolt ons) so its time for a cam and a new rear gear ratio, probibly some roller rockers too. ok - so i was thinking of a zz3 cam and some rockers with 1.6 intake 1.5 exhaust. just was wondering if this sounded like a good setup - im trying to eventually get 320 hp out of the 305 with the addition of heads latter on ... oh and i wanted to know exactly what the ring size is i have 7.5..8.5... also if there is anything else that i need special because of having the post.. whoops that was 3 questions... oh well... thanks - \

kane91z




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91 z28 lb9 5 speed - hooker 1 5/8 headers - high flow cat- full 3 inch exhaust - home made ram air - tpis airfoil - dual chamber flowmaster - Stage 2 Jet Chip and 160 stat - 8 mm Msd plug wires - 55,000 v hypertech coil/rotor/distrib. cap - Mac. White face gauges - lots of sound system crap...

 

uggg - i just read my post -- too many typos - sorry about that - post should be posi and i think you can figure out the rest...

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91 z28 lb9 5 speed - hooker 1 5/8 headers - high flow cat- full 3 inch exhaust - home made ram air - tpis airfoil - dual chamber flowmaster - Stage 2 Jet Chip and 160 stat - 8 mm Msd plug wires - 55,000 v hypertech coil/rotor/distrib. cap - Mac. White face gauges - lots of sound system crap...

 

The ZZ3/ZZ4 cam is probably too big to do any good with stock 305 heads. I'm going to give it a shot w/World 305 heads (see sig) & carb, but even then it is probably a bit much. At least you have the exhaust taken care of. If you don't get different heads, then definately get better valve springs when you put in the cam. The ZZ3 is a dual-pattern cam to assist the exhaust side in keeping up with the intake, so you probably want to stick with 1.5's on both intake & exhaust.

I doubt you're going to get a TPI 305 to 320 hp w/o NO2, especially if you want to drive it on the street. But, I suppose it could be done. It would have to have a lot of flow through the heads, a lot of compression, and a lot of TPI parts replaced.

As for your diff, the 3.08 is a 2-series carrier, so unless you get a new carrier, get gears made for a 2-series. The ring gear is either 7.5" or 7.625" - hmmm, not sure which of those two, but definately not 8.5" or 8.2". My "special" recommendation would be to fill it with AMSOIL Series 2000 75W90 synthetic gear lube when you get the gears/posi in. Great friction-reducing lube, and doesn't need the posi additive.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/LB9 block, ZZ3 cam and intake, WP 305 heads ported & polished, Hooker headers & y-pipe, hi-flow cat).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

Here's the dilly yo: It's probably a bad idea to try to get an old 305 (how many miles?) to that kind of horsepower piece by piece. What will end up happening is that whatever new good performance part you stick in there (cam, rockers, etc) will just end up busting other old parts (springs, lifters, etc). To get to 320 you should plan on a rebuild and map out the 320 from the start. Whether to use the 305 instead of a 350 is a whole different story...good luck.

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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: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, flow tech headers on the way,
engine swap and 4th gen seats in the works...

 

the 305 has about 5000 miles on it ... I know i should have swapped to the 350 but i was short on cash... and parents wouldn't lend me any - i got the 305 for $799 a year ago tomarrow

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91 z28 lb9 5 speed - hooker 1 5/8 headers - high flow cat- full 3 inch exhaust - home made ram air - tpis airfoil - dual chamber flowmaster - Stage 2 Jet Chip and 160 stat - 8 mm Msd plug wires - 55,000 v hypertech coil/rotor/distrib. cap - Mac. White face gauges - lots of sound system crap...

 

Well, you could go through all of that, or you could steal a page form my plan and after getting those gears get yourself into prom burning. There's a lot of power to be had from tuning, and you'll need to be able to do it if you want to get the most from your mods down the road. You can also port your plenum, bump up the FP with a nickel under the FPR lid, maybe port match all your stock intake stuff.
Honestly, i don't like the ZZ3/4 cam much myself. I like the comp Xr series much better. Granted the ZZ4 makes great lift for it's duration, but unless you have some great heads to take advantage of that what's the point. It just makes your valvesprings more expensive. And i don't really like the idea of that big of a difference in duration.
...ed

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Ed Maher - Moderator @ The Carb Board
92 Z28 Convertible - Quasar blue / Tan top
LB9 4L60 GU2 G80 - stock, soon to be sleeper

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

Oh ok totally different story now (well except for the 350 being better). Your engine should be in almost new condition - have you used synthetic after initial break in? Now you can get away with all kinds of things. Depending on what internals were used to begin with, you could do a heads/cam swap without too many repercussions I would think. Ed's absolutely right about tuning - also ask ODB he seems to be a tuning whiz. This is TPI right? Study up on airflow a bit before you choose your heads - with TPI port shape matters a lot to maximize power. You'll also want to look into aftermarket runners that will resonate well with your headers, unless you're getting different headers - you can also add an H pipe to the secondaries to maximize exhaust scavenging. The cam selection is crucial as always but should take into account the header primary/secondary length, runner length, and head specs to put all that horsepower in the rpm range that you want it. Talk to comp cams or some experienced cam guys on here when the time comes. Consider some chassis mods and an aluminum driveshaft. Once you've got the engine where you want it, you can do some reprogramming to get your fuel and spark curves where they need to be for max power at the rpms you want. I think I've covered most of the basics, that's what I'm in the process of doing anyway - but you've definitely come to the right board to do this stuff! Good luck.

Oh and I almost forgot - fully port/polish the plenum, runners and base for airflow, and look into having your tb honed to 51.5mm or so or getting an aftermarket one. Cold air, ram air or whatever are also good ideas.

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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: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, flow tech headers on the way,
engine swap and 4th gen seats in the works...

[This message has been edited by I ROCK (edited February 08, 2001).]

 

I Rock:

Everything you mentioned I have had already planned ( except the h pipe) and Ed I almost bought a pocket programmer a month ago but I bought a new boards an chip for my computer... I was going to port all the intake when I took it off to do the cam probibly in may - I just want to get everything planned out.. although heads and cams are things I basically know nothing about - I've been reading posts on this board for years now and still very rarely see posts about 305 setups - If anyone could post what they have and what they're running that would be great - just keep in mind it is a daily driver - .. thanks

 

BTW...the sep 200 thing is just because i wanted a new name

 

Put some posts over on the electronics board for Tim Burgess and/or Willie - they have some screaming 305's, and Tim is more than happy to share his internal mods. Willie has a page up with his mods too.

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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..."

 

don't think anyone answered the ring gear question, it's 7.5 all you'll need special is gm posi additive

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ICON Motorsports

1st & 3rd

 

thanks ede

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91 z28 lb9 5 speed - hooker 1 5/8 headers - high flow cat- full 3 inch exhaust - home made ram air - tpis airfoil - dual chamber flowmaster - Stage 2 Jet Chip and 160 stat - 8 mm Msd plug wires - 55,000 v hypertech coil/rotor/distrib. cap - Mac. White face gauges - lots of sound system crap...

 

You can't use the ZZ cam in the stock 305 heads anyway. reasons:

1. They don't flow enough
2. The springs need to be changed
3. Even with springs capable the retainers will hit the valve guides requiring machining

All this takin into account it's not feasable to spend the money getting the 305 heads done.