Announcement

Collapse
No announcement yet.

Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

    Sorry for all the questions about such a "not real cool" motor but im not used to having to worry about street friendly stuff and keeping somone else happy. My novas a totally different animal....

    Anyhow heres the blueprint for dads mild 383 for his 70 chevelle....

    350 for now, 383 in another year after rebuild, set comp at 10:1
    -170cc RHS pro torker vortec heads 2.02/1.6 valve, complete
    -Voodoo 262/268, 219/[email protected],.468/.489 lift on a 112. Would the "hot cam" really pick me up that much?
    -1.5 roller rockers {maybe}
    -1 5/8" headers
    -2 1/2" exaust
    -Mallory HEI 85 series dist.
    -Weiand Action plus Q-jet intake
    -Rebuilt factory 750 Q-jet

    -a th350 and a mild stall maybe 2500
    -a 3.42 or 3.55 posi rear end

    how does this sound for dads 70'? Hes looking for somthing that is minimal maintainence, has gobs of TQ and is fun to drive. One question here....are Q-jets any good? Will a holley or demon pick up that much? Just curious also anyone have any ideas or improvement suggestions over this? If not it will probably be my finalized plan.

  • #2

    Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

    Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

    I would put a 3.73 in it to get that boat moving and make it feel like more grunt than it has. Q jets are fine when tuned to the car and no power valves to leak
    2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
    First to run in the .90s .80s and .70's in SBN/A
    2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
    2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

    Comment


    • #3

      Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

      Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

      My brother has had awesome luck with his quadrajet after letting this guy give it a rebuild/tune:

      http://www.thequadshop.net/index.php

      His services are a little pricey, but its tricky stuff unless you have experience. Depending on what parts you already have, it might be more costly than just a carb to switch to a square bore. After one of these rebuilds, I wouldn't think there would be much difference between the quad and a holley/demon, but you can give him a call to feel it out.
      Tampa, FL

      Comment


      • #4

        Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

        Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

        I think Jet does quads as well, great carbs when working as designed...your combo sounds good, maybe a little more convertor, leave the gear at 355, the motor should make lot's of low end and get it moving well enough...

        Comment


        • #5

          Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

          Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

          Also, with a small cam in a carb'd 383 you don't want to spread the lobes too much or you'll be taking away too much of the power offered by the 10:1 CR. I'd think 112 would be the max you'd want to go and the cam you've got picked out might work out pretty good for pops. The downside of going too much tighter is the 10:1 CR, which might be more pump-gas-friendly with 224-226 @ 0.050 and 112-110 LSA. I guess I'm saying your cam choice seems OK-to-conservative and pops might want a bit more duration with a little tighter LSA.

          I'm guessing he has power brakes and might like them, so you don't want to go too tight on the LSA. I had a 383 w/ 10:1 CR and 221 @ 0.050 108 LSA that wouldn't keep a power brake booster working right, even with a vacuum reservoir.

          Most of the newer LS-cams (like the hot cam) I know about have big LSAs with small durations, which seems counter to what would seem to make power. I think the cam rules get different when your cramming the air/fuel in versus trying to suck it through a carb.
          Tampa, FL

          Comment


          • #6

            Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

            Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

            There are a few good books out there on how to tune q-jets. Rochester Carburetors by Doug Roe for example. Either that, or ask around. There are racers out there who are limited to a choice between Q-jets or two barrel Holley's, so a lot of them have learned to tune Q-jets very well.

            Comment


            • #7

              Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

              Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

              Yeah dad has power brakes. Im going to convert to a 4 wheel disc and keep the power assist. So with this in mind, is the cam I have selected going to work with power assist? Whats about the max you can safely go with duration and lobe seperation and still maintain enough vacum to run power brakes? Would the profile I have selected work better with a 110 l/s? HAHA this is all new to me.... My Nova dosent care about cam profiles at all with my 11:1 compression, 5 speed, and manual disc brakes!

              Now as far the Q-jet goes...... It sounds like your all being nice and I should just toss it in the parts bin and get a 650 holley and performer intake.

              Comment


              • #8

                Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

                Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

                My brother has a quad working great on his 383 in a 2nd gen Camaro. It's 10:1 CR, iron heads, CC xtreme energy 268 (224/230 with 110 LSA) with 1.6 roller tip rockers all around. It runs his power brakes no problem. His friend has a similar car with a 9.5 CR 383 running a CC 262 cam. I think the 262 cam might be a little too small for 10:1 and think the 268 would be a little more performance than your initial pick, which I think would work out fine too.

                The con for the quad is it needs some tweaking and will limit your choice of intakes in the future. The pro is having a more unique setup that gives you great fuel economy and all the oompa you want when you hit the pedal.
                Tampa, FL

                Comment


                • #9

                  Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

                  Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this..

                  You could go up to 236 or 242 duration with the cam and use the 2500 stall. It would put the 383 right in it's torque peak which should be around 3200-3600 rpm.

                  I'm running power brakes with Comps XE274 Xtreme Hyd 230-236 dur and 487/ 490 lift at 110 lsa on my 383. I have 15 inches of vacuum at 850 rpm.

                  A lot of people have good luck with Q-Jets after tuning; or you could buy a Edelbrock 750, plunk it on, and forget it. Even will get decent mpg.
                  BS'er formally known as Rebeldryver

                  Resident Instigator

                  sigpic

                  Comment


                  • #10

                    Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

                    Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

                    Lots of good comments so far but I don't know why that trans was not been mentioned. With the turbo 350 and 3.55s first gear is around 9:1. Pretty sad. 3.73 would give you a first gear of 9.5:1. With that fairly tight (but sensible-for-the-street converter) you don't have much leverage to get the boat rolling. With a 700R4 or 4L60E you have great starting ratios and you have an overdrive for mileage. You could drop down to 3.25s and first gear would still be 9.94:1 but overdrive would be 2.27!! That may be a little too low so use 3.55s and low gear becomes 10.8 and overdrive is 2.48! That's a killer starting gear with that converter and the barn-door secondaries on the quad will pop wide open on a WFO start. The q-jet is a fantastic carb. With that carb and overdrive you will get excellent gas mileage but give up nothing on take off. You just need the gear to get the revs up and the air flowing to open those secondaries.

                    You didn't mention fuel but if you can run it on corn then up the compression to at least 11.5. If you use an overdrive trans then run the rear ratio slightly less than the cam's torque peak at your desired cruising speed. ("less" . .. because you always want to go faster ;D)

                    Comment


                    • #11

                      Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

                      Re: Ok ..so the super mild 383 blueprint for dads 70' chevelle looks like this.....

                      I ran a TH350 w/ 3.55s in a 69 Chevelle for 15 years and getting off the line was never a problem. It had a 10:1 383 in it for about 6 years and if you keep the cam small enough, you'll make enough low end torque to offset the 350's 1st gear ratio. I'm not saying a different trans wouldn't shave a tenth or 2 off your 60 foot time, I just don't think you'll notice it much on the street (although an overdrive for the highway would be nice).

                      I've had a mix of experiences with the XE 274 cam and 383s with power brakes. Generally, it'll give you great power with a 10:1 CR, but sometimes 15" isn't enough vacuum to properly run all the different brake boosters out there and work various vacuum operated gizmos (like corvette headlights, actuators in AC systems, and others). Vacuum is tied to overlap and when you go bigger w/ the same LSA you get more overlap and less vacuum.

                      The last cam I had in the 383 was an Isky 280 megacam (232 duration at 0.050 and 108 LSA) and it didn't work the power brakes. The vacuum can I added helped a lot, but only for the 1st hit of the brake pedal. So I could stop from speed but couldn't hold the car at a light for long before the brakes lost their pressure and I'd start creeping forward. I ended up switching to manual brakes and have gotten pretty used to it.
                      Tampa, FL

                      Comment

                      Working...
                      X