I just got my new engine broken in. I used my friends g-tech to see about where i'm at in the quarter mile. It is about 2-3 tenths slow, but fairly accurate. On multiple runs, my car went 13.9 @ 106 mph spinning pretty bad all throughout first gear. The motor specs are:
98 vortec block standard bore
9.73:1 forged pistons
cc306 cam 229/245 duration @ .050 lift, 290/306 advertised duration .510/.540 lift
vortec heads with stock ports, modified for cam (valve springs, .600 lift)
hei distributor with accel module
1 5/8 long tubes with full 3" y-pipe system and a 3" in/out hooker aerochamber muffler
professional products crosswind intake (knock-off of edelbrock performer rpm air gap)
original stamped steel rockers
holley 750 dual feed carb with vacuum secondaries

this is with a 700r4 with a shiftkit, a 3.42 gear ratio, and a 3600 vigilante converter

initial timing is set at 10 degrees and the vacuum advance gives 11 and the mechanical gives 10, so total timing is at about 31 degrees

I'm wondering how much is left. My goal is to break into the 12s. Maybe with a new carb, some timing adjustments, ignition, a good set of roller rockers, and drag radials im hoping i can. How much would getting the heads ported with 2.02 and 1.6 valves, milled, and a thinner head gasket help? What do y'all think?

 

G-Tech is nothing more than a toy - get to a dragstrip if you want truly accurate times. That motor should go into the mid 12's with ease. My old 10:1 Vortec 350 with an XE274H cam went 12.52 @ 108mph on it's first pass.

 

I think 10* initial timing & 10* mechanical gives a total timing of 20*. You need more timing.

 

I checked total timing and it turned out to be 36 degrees by 3500 rpm, which is about where I want it. I also discovered the vacuum diaphragm for the vacuum secondaries on the carb is busted. The secondaries will not open at all. I'm going to try to order a mechanical secondary carb this weekend. Based on the motor specs, what carb would y'all recommend? Alsohow much would having functioning secondaries actually help my 1/4 mile times? The cam likes 6300 rpm, so I'm thinking there will be a substantial difference.

 

so 36 d at 3500 rpm sounds good, but what happens when you open the secondaries? you loose vaccum, so therefore you loose vaccume time advance! Take your distributor out and have it dialed in for mechanical advance ONLY. a good shop will ask for engine specs, compression, fuel type, ect ect, and should only set you back 50 75 bucks or so, plus make sure they give you the print out of the advance graph to make sure they did it properly!!! mine is a computer generated image not hand drawn.

as for the carb if you want speed, go for mechanical, but for daily driver you might think about fixing the vac advance on the one you have unless its due for replacement anyways

COOL? cool

 

Your secondaries won't open when the car is sitting still. You need to watch them while drivng.

 

I bolted a brand new holley street avenger 770 cfm on and the difference is like night and day. I have yet to test it on the g-tech. It runs so much crisper. It is impossible not to spin the tires punching it from less than 30 mph. from 4500-6500 rpm it really pulls now. I'll post an update s soon as I can get ahold of my friend's gtech or take it to the track.

 

With the same g-tech it went 13.6 at 110mph. This was in the middle of the day at 97 degrees compared to the 70 degrees the initial run with the other carb was at.

 

Ran what I could through comp cams calculator.

try slicks.

 

or drag radials. you WILL hit 12's. end of story.

 

I just wanted to update for anyone who is interested. The plug wires I initially used were old and cracked and i had electrical tape on just about all of them. I junked the summit ignition crap. After some fine tuning with the new carb and a set of plug wires, coil, and module, it ran 12.94 at 115 mph on a 2.79 60 foot on 245/45/17 street tires at the track. I almost made a mess in my pants. Im hoping for low 12s with a set of DRS. I still don't have roller rockers.

 

From that mph you should have low 12's in the bag if you can hook up.

 

you have low-mid 11's. plain and simple. i run 11.6's @ 116mph. you will gain mph when you hook up.

 

Care to share anymore info on the engine build? Any that isn't already stated above?
It looks like a very budget friendly combo.

Thanks.

 

Wow, I'm amazed that this combo ran so well, good job!