Fast 95 Z28

So last night I finally ran my 1970 firebird down the 1/4 mile after a year or so of building it. I personally thought the car was going to trap at least 120mph. Heres the specs on the car. The car turned a 11.48 at 116.88mph in the 1/4 and a 7.3ish at 95mph in the 1/8 mile. My best 60' foot was a 1.676

LQ4 408 stroker

4.030" bore

Quench .037"

Wiesco -8cc forged pistons

Eagle forged 6.125 rods

Callies Compstar 4" forged crank

ARP 2000 rod bolts

Comp cam hardened 7.400 pushrods

LS7 lifters

Stock LS3 heads with 2.16/1.59 valves

Lunati Gold Dual Valve Springs .660 lift

Unported Victor Jr.

Pat G Cam (231/242 .615/.617 110)

Dynatech 1 7/8" long tube headers into 3" X pipe and 2.5" sweet thunder mufflers and cut outs after the headers

Quick Fuel Carb 750cfm mechanical secondaries

Static compression ratio... 10.7:1

Dynamic compression ratio... 8.49:1

3000 Stall Converter

Turbo 400

Denny's nitrous ready driveshaft

12 bolt with 3.73 posi

275/60/15 Mickey Thompson drag radials on aluminum wheels

Shifting at 6800 with rev limiter at 7000rpm

Weight of car probably in the 3400-3600 range.

I think my base timing was set at 20 degree and max was 33 degree, can't exactly recall.

I was foot braking leaving the tree at 2600rpm and running a small 10" paper air filter since thats all that fits under my shaker scoop currently. I think the air filter is really hurting me and running with the cutouts closed. Since this was also my first time running the car it doesn't have the proper AFR. I also have skinny front tires to put on the car next time!

I'll appreciate any opinions from people... I just thought the LS3 408's should trap in the 120's.

Thanks

black00ssFL

iTrader: (24)

1/4 mile time is pretty good considering the 60' and mph. Maybe losing some on the top end from that filter. Could try a little more converter stall, maybe 3500-3600, don't know how much you drive on the street though.

Max timing might be a little high. Remember with these lsx engines, just because it's taking the timing without knock, doesn't mean it's making more power.

Oh, and what was the DA?

thunderstruck507

iTrader: (18)

Looks like it's running pretty well for the first time out.

Air filter, cutout closed, and improper air/fuel...you pretty much answered your own question in the post.

Your car is running pretty much identical MPH in the 1/8 and 1/4 as mine, but .2 faster in both on a similar 60ft and similar weight. Do some tuning and it will pick up. The TH400 is going to hurt your MPH though.

Fast 95 Z28

I'm racing at sea level, Sonoma Raceway, aka Infineon/Sears Point. Yea its a street/strip car I had originally planned on getting a 3500 stall but found a killer deal on the tranny and stall for 500 bucks... so figured I'd run that and see what it did. I was just concerned on how much power my engine is making due to the low MPH. I was under the impression a 408 LS3 should be making at least 550hp, not sure if I messed something up in the build or not? Even though horsepower doesn't matter only ET's! I'll post some videos later of the in car and outside the car.

Fast 95 Z28

Are you running a LS1 346? I would think I'd be a bit faster with the extra cubes I have?

thunderstruck507

iTrader: (18)

Yes I am running a stock shortblock ls1. Cubes can bring more power but often not as much as people think comes from cubes alone as it does from the ability to run larger cam and heads effectively.

Your biggest thing is that you need to get the air/fuel tuned. It could be costing you all the MPH you are looking for alone, never mind if it's starving for air through the filter.

Fast 95 Z28

Heres the two videos of the car:

In car:

http://www.youtube.com/watch?v=JUs0l...ature=youtu.be

Outside of car:

http://www.youtube.com/watch?v=IPIk3...ature=youtu.be

Blackbird-WS6

iTrader: (15)

did you have pat-G spec the cam for those ls3 heads?

CR is little low for a 408. i like to see them around 11.75cr range

you looking for 550 at crank or wheels??

Fast 95 Z28

Pat G did spec that cam for my setup. I'm looking for 550-600hp at the crank and I kept the compression ratio lower for pump gas and I thought dynamic compression was more important than the static anyway... which I had specced for the most on 91 octane.

Blackbird-WS6

iTrader: (15)

i say get everything sorted out like AFR and good filter/cutout open and see what it does then report back to see if anything changes.

moge11

More Compression(11.5+:1), More Cam(24x/25x or BIGGER), More carb, and 4800+stall

murphinator

iTrader: (2)

You seem content with the et but bummed about the trap...I have a second gen TA also , my first thought is that a second gen is a brick compared to a 4th gen and trap will suffer when you have worse aerodynamics here is a pic of my 2nd gen parked between 2 of my 4th gens , look at the difference in how upright the windshiled is in particular - I also have a 10" filter up into my shaker but on a 400 pontiac slug , needs an ls lol

Fast 95 Z28

Nice TA by the way! Yea my car is like a 4x4 right now since it has the original front pontiac springs and it raised the front by like an inch, so the aerodynamics are especially suffering... Those pontiac engines are super heavy i think it was like 650 pounds! I guess you know my pain with how limited we are with air filters and the shaker scoop.