89bonestockiroc

I was just wondering if the plenum is any different on a 305 tpi car than one with a 350. I wouldnt think there is, but im looking for an extra one on ebay just in case i screw up while porting it.
Thanks

kwikgta

yes

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92 GTA(only 226 made)ort matched sportsman heads with 2.05 valves,64 cc,milled .015,.028 head gaskets,port matched Accel runners,port matched plenum,port matched edelbrock intake,flow matched injectors,jet hot headers and 2.5" mandrel bent exhaust,Flowmaster muffler,underdrive pulleys,slp cam,1.6 rockers,slp cold air induction,52mm throttlebody,performance resource custom chip,Dyna module,Screamin Demon coil,Accel 8.8 wires,Bosch platinum plugs,timing at 10 degrees,tb bypass,relocated map sensor,shift kit,Fairbanks billet servo,pump vane kit & 2400 stall,Torque converter lockup switch,3.42 posi with welded axle tubes,Zexel Torsen HD diff.,Summit rearend girdle,solid pinion spacer,& alloy axles.Boxed panhard bar,lakewood lca's & edelbrock strut tower brace,Jeg's torque arm,Jegs welded in subframe connecters.Performance friction pads,turbo slotted front rotors,stainless braid brake lines.Roh ZT 17x8.5 front wheels with 255/40ZR/17 tires. 17x9.5 rear wheels with 275/40ZR/17's on the street.Hoosier 26x9.5 slicks on the strip.

theformula

There is no difference. Even the throttle body is the same. 48mm.

When you port, just be careful doing the walls. Also, you may want to duct tape around the entry ports so you don't shape them too.

Anyway, the most important restriction to get rid of are the walls right behind the entry ports.

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'92 Formula
305 TPI
Mods: SLP catback,SLP air foil,ported plenum,Crane AFPR (49psi),MSD6AL,homemade cold air,K&Ns,3:73s,JET fan switch...SLP 1 5/8ths are coming...oh yes

Kevin91Z

iTrader: (1)

The 305 and 350 TPI hardware is identical. The only difference is the injector size. The 305 TPI uses 19lbs injectors and the 350 uses 22lbs injectors. Everything else is the same from the intake manifold up to the plenum.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

IrocManiac

There is no difference.

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TPI 305,
Gutted airboxes,
gutted MAF,
K&N filters,
Corvette Servo.
14.9@93mph

"Speed kills, wanna live forever, drive a Ford."

8Mike9

Bonestock, keep in mind that pre-89 plenums will be different than your '89...you can use the '90-92 SD plenums as well, by just plugging one hole where the MAP line was plugged to.

Ozzy88GTA

If they are both the same, why is it that when I E-Mailed TPIS about their airfoil for my GTA they said that the airfoil for the 350 will not fit my 305.
Just wondering.

Ozzy88GTA

Correction!!!
I had E-Mailed Holley and not TPIS.

Guest

Because they dont know what they are talking about?

BTW the airfoil has nothing to do with the plenum, but the throttle body instead. Those are the same on a 305 and 350 as well.

Kevin91Z

iTrader: (1)

An airfoil should fit 305 TPI, 350 TPI, and 350 LT1 throttle bodies with no trouble. Yes, thats right, it will fit 85-97 TPI/LT1 throttle bodies.

Ozzy88GTA

Didn't mean to get off the plenum subject but thought I would just get it cleared since Kevin91Z said that the hardware was the same. Thank you.