I know this has been asked before by others and by me but, no one ever really tells me anything. The car is a 85 305tpi Trans am. I want to get the et down to low 14's. Can someone with a 305 tell me the parts they used and the times there getting. I know the 350 swap would be better but I want to prove a point with the 305. I've done all the free mods. With new heads,headers could I possibly be in the mid 14's.

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85 305tpi Trans am
flowmaster exaust
K&N air filter, 4:11 rear gears

 

you need headers and a gutted or high flow cat converter. and NITROUS BABY!!!!!! that is the easiest way without tearing the motor apart to swap heads and cam. oh yeah almost forgot, you could port the intake plenum and buy bigger runners and base too. maybe even a bigger throttle body, like 58mm.

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86 IROCZ
T-Tops
700R4
305 TPI
3.23 gears
shift kit, manual TC switch, manual fan switch, flowmaster exhaust with edelbrock TES headers& hollow cat, gutted MAF.

[This message has been edited by raging86 (edited April 18, 2001).]

 

I don't have any time slips, but after I ported the plenum, make a cold air intake (much needed on our cars), and added Edelbrock T.E.S. headers, I noticed a HUGE differance. I think a chip would be the next "easy" step for me to take, before looking into doing a cam.

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Rob
'86 TA 305 TPI
Gutted MAF, Ported Plenum
TB Bypass, Home made Cold Air Intake,
Edelbrock T.E.S.

 

Yeah I have an 85tpi Iroc and we're lucky cause we didn't get the peanut cam which means our mods should go further then the smaller cammed cars. This year I'm getting headers, high flow cat, catback and cold air and I'll tell you how it goes

 

RDog,

The cam is more of a limiting factor than the heads. Neither is stellar in design, but the cam profile of the typical 305 TPI is very restrictive. Actually, the 350 is not a great deal better, but is better nonetheless.

The biggest gains you will accomplish will start with the cam, then heads or head modifications to compliment the cam. Since you cannot install monster valves in the 305 chambers, you are limited to getting flow through valve lift, not size. Slightly larger valves will help, but will not make a major difference with a stock TPI cam since you can only squeeze 1.94/1.60 valve in a 305 head before clearance and shrouding become a problem.

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Later,
Vader
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"What a Day..."
Adobe Acrobat Reader

 

well someone reccomended nitrous, and to me, thats the easiest most effective way to get you into the 14's and easily past, (depending on how much you use) theres several other way, 58 MM throttle body not one of them, runners, don't, plenum, no, and manifold not nessecary, you see it just puts the little 305 "on it's nose" it gives it more midrange upper end but the problem is you lose a ton of torque, and not to mention a ton of money, if youve got a huge cam sucking in a lot a lot of air, then you need those things, if not, its a waste, and youll lose a lot of torque! and what are the TPI's built for? mostly throttle response and torque. my suggestions to you would be to use a little nitrous, 100-150 depending on how lucky you feel and how your motors running, next l would put in a decent rearend, a 3.73 would be perfect, after that a shift kit, and a decent stall converter. after all of that you may need to consider a good pair of tires, and with all of those mods youll be easily into the low 13's if not better without sacrificing much drivability. just remember you dont need to open up the intake much more unless youve got constantly used forced induction or lots of compression, or a high rev cam!

good luck!

 

As an example, I know this member, and his times with a new LT1 'B' body cam (@.50 418/430, 194/199, LSA 111) increased as follows:

* Old cam best time: 15.414 @ 87.47.
* New cam best time: 15.006 @ 89.55.

The rest of the car was about the same, with these mods:

87 Z28 305 TPI, Auto, LT-1 cam , roller timing set, 2.73, Gutted air boxes, K & N fillters, Dyno Max 3" cat back, 8.8 mm spirals, air foil, and 170* Stat.

A cam with even more lift and an AFPR to take advantage of the extra air flow would probably cut times well into the 14's, and this is with stock heads and plenum.

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Later,
Vader
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"What a Day..."
Adobe Acrobat Reader

 

Vader,
What cam should I run? Any part numbers or info to what would be a good one for my 85 T/A. Or should I convert to roller type cam?

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85 305tpi Trans am
flowmaster exaust
K&N air filter, 4:11 rear gears

 

[QUOTE]Originally posted by Vader:
[B]As an example, I know this member, and his times with a new LT1 'B' body cam (@.50 418/430, 194/199, LSA 111) increased as follows:


It won't do much good he already has a cam that has these specs
Lift: intake .404
exhaust .415

Duration: intake 320
(crank) exhaust 320

so he might get .1 or .2 with that LT1 cam too much of a hassle for no reason. I say go with headers, exhaust, cold air and then go from there

 

Listed below are my mods and times with the 305.

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29

 

Start with bolt ons first and see how the car reacts. THEN, if NEEDED you can go to the major things (ex: cam/heads). Be prepared to have the car off the road for a while if you plan to do a cam/heads package.

If I had your car, I would first start with free mods.
1. Build a good cold air setup. Check the tech section or email me

2. Port your plenum

3. Gut your cat,

4. Adjust timing

Then move on to bolt ons
1. Air foil ($30)
2. headers ($300-$450)
3. catback ($200-$550)
4. maybe runners? ($250-$400)
5. msd ignition box ($170)
6. Custom prom ($300)

Believe it or not, all of the above doesnt always give the expected results. Make sure your car is all tuned up before the modifications. If you dont achieve your goal of low 14s with the mods above. Then it is time to move on to other things

Gears (3:73s...3:42s etc..) $160 gears
$100 installation kit

$200-$300 labor

Cam-$275 for a roller cam (you don't have a roller cam by the way)

valve springs for cam-$80

Heads-$800-$1600

Also, if you have an auto...there are other mods. Corvette servo, TC.etc.

Good luck. Theres a lot of help around here, you'll be ok

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91 Formula 1LE 1 of 46
305 TPI 5speed
1LE/G92/WS6

Paxton SN92 supercharger, Ford SVO 24#injectors, Crane AFPR,SLP airfoil, ported/polished plenum, March alt. pulley,Crane Gold 1.6rrs,MSD coil,MSD6AL (5400rpm limit),Holley 9mm wires,Ac delco R43ts plugs,custom chip,Bosch O2sensor,SLP 1 5/8" headers,SLP catback,shortened shifter,3:73s w/Auburn posi,180* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.