It almost seems like a crazy question, I know. I'm talking w/o NOS. My mods so far are: Headers, high flow cat, Flowmaster 80 series, modified cold air induction, MSD-6A, Hypertech Thermomaster, and the norms (Bosch Platnums, wires, cap & rotor). I've removed the back seat, spare and jack. I have a shift kit, but a T56 is going to be installed within the next couple of months. The mods I already intend to do are: 1.6 rocker arms, new cam, new heads, underdrive pullies, and a 3.73 rear end. I need opinions on the best cam and heads to get, as well as anything else that would help. I also want to hit 300hp and 350 ft/lb of torque, while keeping a/c and power steering. Any tips, or am I just better off finding a 327 or 350 block and going from there. If I did do that, would I be able to achieve the numbers I'm looking for with TBI? Thank you - Roy

 

Have you done a search? There have been a large number of posts on this topic, and a lot of questions already answered. Not to be an ***, but it is a well covered topic...

 

Hot Rod magazine ran high 12s with an L69 powered Z28 in 1983! With the stock bottom end (except for the cam)! This engine was carbed of course, but I bet you could achieve similar results with a TBI system. Here is a list of parts they used:

Holley 650 double pumper
041 casting heads with 1.94 intake and 1.50 exhaust valves
Edelbrock Victor Jr. intake manifold port matched to the heads
Comp Cams 292 High Energy Magnum hydraulic flat tappet described as follows; "valve lift is .501 inch with 244 degrees duration at .050 inch lift and 110 degree lobe centers"
MSD-6A
Hooker 1 3/4" primary headers
4" K&N filter
Supreme Super C Turbo mufflers

They claim high 12s with this setup (with NO suspension mods). They also describe this combo as "very streetable"! With todays technology, these results should be easily duplicated.

 

83 z28 only has like 150hp correct?

 

oh yeah not to long ago in super chevy there was an article about a "budget 13 second 3rd gen" or something like that...just had a new cam, and nitrous...it was carbed tho had like a 650cfm edlerbrock or something...still if you wanted you could go carb for about 500$ and run new heads, cam, intake, headers, and if you slapped NOS on there and it was tuned right who knows

 

No. The L69 'High Output' 305 (which this build up was based on)was factory rated at 190hp. I've got a crappy scan of the article if you want it.

 

Thankyou for the replies everybody. Have a good new year!

 

The low 13's would be difficult to get into with a 305tbi without NOS or a supercharger. I have a lot of mods on my 91 Formula 305tbi and I run 13.821 at 101.563 on street tires.


1991 Pontiac Firebird Formula 305 TBI
Purchased 7-16-90.
49875 original miles (2-22-01).
Synthetic oils and grease.

Modifications -

Edelbrock TBI Performer intake.
TBI modified by Turbo City to flow 565 CFM.
TBI bonnet 1-inch spacer.
Auto Meter air/fuel ratio monitor.
Crane roller tip/needle bearing fulcrum Gold Race Rockers.
SLP cam - Dur. @ 0.050 0.209/0.214, Lift 0.471/0.490, 112° CL.
K&N air filter.
Bosch platinum plugs.
Accel 8mm spark plug wires.
SLP Tri-Y 1 5/8th-inch headers MCCI coated inside and out.
Flowmaster two chamber cross flow muffler.
Custom 3” Cat-Back exhaust system.
Random Technology 3-inch catalytic converter.
Auburn posi.
Richmond 4.10 gears.
TA Performance Products rear end cover.
Dacco 2500 stall torque converter.
Hayden transmission oil cooler.
Darrel Young 700R4 TV Valve 0.521.
Fairbanks 2-4 Billet Servo (700R4)
B&M megashifter.
Paxton supercharger.
Adjustable fuel pressure regulator-external to TBI.
Corvette fuel pump-inside tank.
Vacuum-Boost & Fuel Pressure gauges-mounted inside car (isolator mounted on firewall).
ADS custom chip (primary), Hypertech Thermomaster (secondary).
160° thermostat.
MSD 6AL ignition.
MSD Blaster 2 coil
MSD tach adapter.
MSD adjustable timing control.
Trunk mounted battery.
Mickey Thompson Indy Profile S/S tires, rear.
Crager Drag Star polished aluminum wheels, 15x8.
Monroe adjustable air shocks, rear.
South Side Machine weld on Sub Frame Connectors.
Cloyes double true roller timing chain set.
Cyberdyne speedometer calibration box.
Mildly tinted windows.

 

i would have to disagree on that. i am not gonn alie and say that running a low 13 with a 305 N/A of any kind is easy. but it can be done now that we have all put our heads together and come up with the basic out line for speed in a LO3.
most of the things you need are things you woudl do to any car with any motor, things like headers, high flow cats, 3inch cat backs, posi, gears, open element/ cold air intakes, better intake manifold are all common in any performance motor.
the things to look at extra in a 305 tbi is that it can use a good set of heads to replace the stock swirl poops. even with the swirlies you can still run some very impressive numbers, nhra stock class rates our engines as 12.60 for index racing, and that is with no real head work allowed and stock sized valves.
the real weak link of these engine s from the factory is the cam, but sionce the budget replacement of the stock LT1 cam was found($20-50 usually) there is little need to go hunting for the "perfect stick" in any catalogs.
the biggest thign to remeber though when talking about a particular ET goal is that traction and proper gearing are the two most imporrtant things to gettign max ET out of any car.
305TBI, you said you went 13.8 at 101mph, that is a sign of severe wheel spin. you are clearly making the power to get the job done, but that ET shoudl be closer to a 13.4 with that kind of mph. please don't take that as a flame, i am just using you as an example.
i put up my list to run low 14's on a budget a while ago(about a month and a half i think), if you guys want i can put up the big version that shows how to put an N/A 305TBI into the low 13's. this version of the list includes a bunch of things that cost a lot more money and even stages of soem mods from cheapest to most expensive.

later
tim

 

Yes, I would be interested in seeing that list!

 

i hafta write it all out on paper so i don't miss anythign first. i will try to post it up on tuesday. it is gonna be a two part thread. one part about building power and one part about chassis and suspension.

later
tim