I should be hitting 13.11 next May in my current form with the good air. I know there are a lot of variables so I am going to throw out just a few questions:
Switch from Holley 670SA to Holley 750?
Change torque convertor stall from 2400 to maybe 3000?
Switch from current Comp Cam XE268 to Lunati Voodoo 60103?
Go on a diet and lose 100 pounds???
Bowtieman427 said
Jan 6, 2013
Need more details on your car and current setup What is the car running now ? 100lbs is worth a 0.1s
4-door Chevelle said
Jan 6, 2013
Best time last May was 13.22 but I just lost 100lbs when I pulled out all the AC stuff. My old Chevelle without AC or front discs best time was 13.11 with this drive-line in it.
Bored .060 over, 10-1 pistons, Summit cast iron heads 2.02 1.60 165cc intake and 72cc chamber, head and intake port work done, Edelbrock Performer RPM Air-gap intake, 1" 4-hole spacer, Holley 670SA, Holley mechanical fuel pump, Mallory Unilite, MSD 6AL (installing as we speak), dual electric fans.
TH350 with B&M Transpack and Midwest Performance Convertor built for 2400 stall.
Eaton posi with 3.73 gears.
26" tall slick.
Pedal to the metal.
Bowtieman427 said
Jan 7, 2013
On the carb. What helped me gain a few tenths was simply adding a Holley jet extensions and a notched float kit. The secondaries were starving at launch and it even trapped higher. Chevelles like to stay nose up when flying down the track keep gas away from the secondary jets. Do you have hook well ? what are your times and speed down the track 60ft, 1/8th etc ? ironically the 100lbs is worth 0.1s as you have already proven : ) Not sure where your torque curve is but when you go higher stall it will hit harder off the line. every 0.1 you shave off 60ft time is worth 0.2-.0.4s at the 1/4 mile. the 60ft. My 60ft times are all over depending on how well it hooks. Perhaps chat with Midwest convertor and see what there thoughts are. Are you jetted to highest trap speed ? I have not played around with this on my car yet. Still playing around with to many other things to make it safer and more rugged. What track are you running at ? I went with Steve S a few times to CF, IA and it is great I also go to RF, WI on muscle car days and club day.
4-door Chevelle said
Jan 7, 2013
I don't know much about the jet extensions and special float but I can look in to that.
I have adjustable upper control arms, boxed lowers, sway bar and individual supply lines on the air shocks with 60psi.
I hook well and rarely have problems. The occasional spin of the tire off the line is pretty rare for me.
My combo is pretty much built around a power curve between 2200 and 5800rpm.
60ft times are just over 2.00.
I will call Dick at MPC.
I haven't had a good test day at the track for a few years, maybe next year in May.
My home track is Brainerd but I run Rock Falls and Grove Creek. I also run with MDRA.
I am about to go 0 MPH, good night.
Scott Parkhurst said
Jan 8, 2013
What rpm do you shift at?
4-door Chevelle said
Jan 8, 2013
Being it starts to break up at 6,000 I usually shift at 5,800.
Scott Parkhurst said
Jan 8, 2013
Okay- you need to fix that.
Whatever is 'breaking up' is costing you power. Valve float, ignition..whatever it is.
That engine should pull to 6500 easily. You're leaving power on the table by not being able to get up there. Remember- RPM is part of the horsepower formula. The more rpm you can get, the faster you can go.
Naturally, you then adjust rear gear ratio so you hit the finish line at the redline in top gear...
-- Edited by Scott Parkhurst on Tuesday 8th of January 2013 04:19:21 PM
Scott Parkhurst said
Jan 9, 2013
Also- you need bigger heads. I run 210s on my 383. 165s are itty bitty. You should have at least a 190cc intake port.
I've got a few other ideas for you too...but heads are a huge reason you've plateaued here.
Bowtieman427 said
Jan 9, 2013
That 268 cam and small heads are good to 6500RPM in SBC ? Not sure it could pull to 6500RPM on its best day. It is a hydraulic flat tappet cam with not much lift or duration. I could be worng too as I often am, but I think he would have to rethink the cam, heads and valvetrain to get to 6500RPM reliably. 5800rpm for Comp 268 in chevy 350 +60 over 10:1 is about right to me and even a bit optimistic in his setup. Got the same cam in 427 BBC and it rolls off at about 5400-5600 RPM with Rec port heads and 3x2 setup granted more cubes but bigger heads too. I really do not think there would be that much gain going to the Lunati Voodoo 60103 vs the Comp 268 they are very simliar grind a littlle more lift and duration going to the lunati which may help, but I think the power change would not even be noticable if any as it is so little difference. I think the 268 in his setup is pretty good. He put in a MSD ignition which should help it out a little. I have a Mallory Hyfire with unilite dizzy and it never breaks up and I have taken it to 7000RPM with no issues.
How much $$ you got to spend ???
Loose the 100lbs : ) it is cheaper.
4-door Chevelle said
Jan 9, 2013
I actually think the breaking up is a lean condition at that high RPM. When I use to push it anyway I would see sppots on my plugs which I believe may be detonation? Unfortunately, being a MultiPurposeVehicle I have to make sacrifices in places I don't want to but I still do want to "do it all"! I agree with what you say Scott ... the pocket book says no though. With the 60103 only being a little more cam that might be enough to get me that tenth or two at the track?!? Plus, I don't like the sound of the XE cam cause it doubles as a sewing machine.
Scott Parkhurst said
Jan 9, 2013
I meant that it should rev to 6500.. Without breaking up. I'd bet it would nose over and stop making power around 6000. But still...you get the idea. I'd bet your valve springs are contributing to the breakup....but, if you want to go faster, that's where you'll find the most gains right now.
Naturally, a bit bigger cam will work better up there too. You could run more cam without completely losing street ability.
Bowtieman427 said
Jan 9, 2013
You have added two more variables to the question. The current cam and upper needs attention and possible leaning out ?
The lean out can be fuel starvation and possibley not the carbs fault. Do you have both carbs in hand already ? Are you able to check fuel pressure at WOT ? Are you running headers ? I was welded a bung on the collector and have a wide band O2 sensor AFR meter. The thing is great help me track down fuel issue and tuning carb. If you have to recam the Lunati Voodoo 60103 cam you picked should be very nice looking per the specs and your current setup. It should work very well.
Kit Part Number: 10120703LK "This High Performance street cam likes 2400 RPM stall, 700 cfm carb, dual plane intake and headers. Makes un-equaled power to 6200 RPM with proper valve springs. If you're looking for a Very Strong cam with great street manners then this cam is it. •Advertised Duration (Int/Exh): 268/276 •Duration @ .050 (Int/Exh): 227/233 •Gross Valve Lift (Int/Exh): .489/.504 •LSA/ICL: 110/106 •Valve Lash (Int/Exh): Hyd/Hyd •RPM Range: 1800-6200"
The next one up will work too, but the one you picked may be better. Kit Part Number: 10120704LK Hydraulic. Hot Street cam, likes 2800 converter, Hi-Rise type dual plane intake with 750cfm carb, headers, 10:1 compression and 3.73 gears. Likes up to 200HP nitrous.
Ok here is my on this. You have a car that runs, drives nice, and overall seem pretty happy with. You go to the track maybe 4-5 times a year?? If you really want to go faster put NOS on it. Cheaper than a cam and converter swap you are considering. I would think you would only need a 100 shot to get the results you probably want. All the things you are wanting to do are going to make the car less streetable to a degree and in the long run may end up regretting in my opinion.
I should be hitting 13.11 next May in my current form with the good air. I know there are a lot of variables so I am going to throw out just a few questions:
Switch from Holley 670SA to Holley 750?
Change torque convertor stall from 2400 to maybe 3000?
Switch from current Comp Cam XE268 to Lunati Voodoo 60103?
Go on a diet and lose 100 pounds???
What is the car running now ?
100lbs is worth a 0.1s
Bored .060 over, 10-1 pistons, Summit cast iron heads 2.02 1.60 165cc intake and 72cc chamber, head and intake port work done, Edelbrock Performer RPM Air-gap intake, 1" 4-hole spacer, Holley 670SA, Holley mechanical fuel pump, Mallory Unilite, MSD 6AL (installing as we speak), dual electric fans.
TH350 with B&M Transpack and Midwest Performance Convertor built for 2400 stall.
Eaton posi with 3.73 gears.
26" tall slick.
Pedal to the metal.
Do you have hook well ?
what are your times and speed down the track 60ft, 1/8th etc ?
ironically the 100lbs is worth 0.1s as you have already proven : )
Not sure where your torque curve is but when you go higher stall it will hit harder off the line. every 0.1 you shave off 60ft time is worth 0.2-.0.4s at the 1/4 mile. the 60ft. My 60ft times are all over depending on how well it hooks. Perhaps chat with Midwest convertor and see what there thoughts are.
Are you jetted to highest trap speed ? I have not played around with this on my car yet. Still playing around with to many other things to make it safer and more rugged.
What track are you running at ? I went with Steve S a few times to CF, IA and it is great I also go to RF, WI on muscle car days and club day.
I have adjustable upper control arms, boxed lowers, sway bar and individual supply lines on the air shocks with 60psi.
I hook well and rarely have problems. The occasional spin of the tire off the line is pretty rare for me.
My combo is pretty much built around a power curve between 2200 and 5800rpm.
60ft times are just over 2.00.
I will call Dick at MPC.
I haven't had a good test day at the track for a few years, maybe next year in May.
My home track is Brainerd but I run Rock Falls and Grove Creek. I also run with MDRA.
I am about to go 0 MPH, good night.
Okay- you need to fix that.
Whatever is 'breaking up' is costing you power. Valve float, ignition..whatever it is.
That engine should pull to 6500 easily. You're leaving power on the table by not being able to get up there. Remember- RPM is part of the horsepower formula. The more rpm you can get, the faster you can go.
Naturally, you then adjust rear gear ratio so you hit the finish line at the redline in top gear...
-- Edited by Scott Parkhurst on Tuesday 8th of January 2013 04:19:21 PM
I've got a few other ideas for you too...but heads are a huge reason you've plateaued here.
He put in a MSD ignition which should help it out a little. I have a Mallory Hyfire with unilite dizzy and it never breaks up and I have taken it to 7000RPM with no issues.
How much $$ you got to spend ???
Loose the 100lbs : ) it is cheaper.
Naturally, a bit bigger cam will work better up there too. You could run more cam without completely losing street ability.
The lean out can be fuel starvation and possibley not the carbs fault. Do you have both carbs in hand already ?
Are you able to check fuel pressure at WOT ?
Are you running headers ? I was welded a bung on the collector and have a wide band O2 sensor AFR meter. The thing is great help me track down fuel issue and tuning carb.
If you have to recam the Lunati Voodoo 60103 cam you picked should be very nice looking per the specs and your current setup. It should work very well.
Kit Part Number: 10120703LK
"This High Performance street cam likes 2400 RPM stall, 700 cfm carb, dual plane intake and headers. Makes un-equaled power to 6200 RPM with proper valve springs. If you're looking for a Very Strong cam with great street manners then this cam is it.
•Advertised Duration (Int/Exh): 268/276
•Duration @ .050 (Int/Exh): 227/233
•Gross Valve Lift (Int/Exh): .489/.504
•LSA/ICL: 110/106
•Valve Lash (Int/Exh): Hyd/Hyd
•RPM Range: 1800-6200"
The next one up will work too, but the one you picked may be better.
Kit Part Number: 10120704LK
Hydraulic. Hot Street cam, likes 2800 converter, Hi-Rise type dual plane intake with 750cfm carb, headers, 10:1 compression and 3.73 gears. Likes up to 200HP nitrous.
•Advertised Duration (Int/Exh): 276/284
•Duration @ .050 (Int/Exh): 233/241
•Gross Valve Lift (Int/Exh): .504/.525
•LSA/ICL: 110/106
•Valve Lash (Int/Exh): Hyd/Hyd
•RPM Range: 2200-6400
Ok here is my
on this. You have a car that runs, drives nice, and overall seem pretty happy with. You go to the track maybe 4-5 times a year?? If you really want to go faster put NOS on it. Cheaper than a cam and converter swap you are considering. I would think you would only need a 100 shot to get the results you probably want. All the things you are wanting to do are going to make the car less streetable to a degree and in the long run may end up regretting in my opinion.