Took my sport mod out to chow speedway, did fine didnt run hot or have any problems. only issue i was having is at top speed down the stright away it dont seem to run as smooth any idea? its not falling on it face just kinda of sputtering

this is what im running for motor
350 bored 60 over stock pistong rods and crank stock 76cc 441 heads. victor jr intake holley 4412 crab 76 jets, stock hei distributor timing advance is at 34 degree, jr motorsport camshaft 531 542 lift

was thinking i might have to much advance for a stock motor would that cause any problems?

might try newer plugs and wires and see what happens any tips would be greatly aprreacted

What RPM are you turning?  Might be starving for fuel?

What sprark plugs are you running?   Have you taken a plug reading...this might be a good plae to start looking.

streetstockracer wrote on 08/16/11 at 12:59pm:


What he said. Your cylinders are not making enough "suck" to get a proper signal to the carb with that intake/cam. Find one of those generic dual plane intakes and you should be more gooder. More advance shouldn't hurt but remember, it's a more of a crutch than a cure. Moving the cam forward to the next area code is would help a little but is just another crutch.

In the big picture, you might consider shopping for some tighter chamber head castings. Hope this helps.

Edit. I mis read your post. Everybody has given good advice, but if it's laying over on the top check the fuel pressure.

Hey Dave...Those are big jets for a 4412...IMO...When we got our gauge legal 4412 from Willy's, it had 73's in it after their dyno pulls, with the adjusted altitude and plug reading we went down to 72's and stayed there pretty much. This was a 14:1 360, Dart head, 254*/605 lift solid at 8000 rpm. Wlly's said that the 4412 will only flow so much air and don't use is carb as a crutch when I told him that we had 78's in the old 4412...He got offened, we listened to him and by far the best 4412 we ever ran!

Dave... you are right and VDL runs 73 out of the box, but remember these are modified, the emulsion tubes are changed and they massage the channels and boosters. Ive found The standard unmodified 4412 runs good at 78 jets.

49mod...right on the voltage and the stock module limitations.
Recent experience on the DUI.... one blown motor due to the pickup confusing cylinders 7 and 8. One sour running motor due to the pegs that hold the advance weights coming loose. Both returned to DUI and confirmed. Sorry that performance is out of my budget.

Dave... I opened a new VDL 4412 and a off the shelf 4412 and measured the power valve fuel ports. I don't remember the exact numbers, but the VDL was opened larger than stock. Hence the smaller main jets. I think the idea was to make a better transition from the main to power valve circuits. I wrote the numbers down somewhere, but without the info on the booster and emulsion tubes its only info.

FYI... my new VDL 7448 350 cfm carb for the IMCA stock car has 83 jets! VDL says thats what is needed for that carb..

it JR MOTORSPORTS PRC 108 CAM SOLID CAM

You may already know most of this, I'm just tossing out my best help.

Voltage is more important when using an OEM style HEI than when using a spark box (6al) type ingnition.  Battery must be healthy.

I run an OEM style HEI.  I run 0 size cables all the way from the battery to the starter.  The NEG cable directly to the outer starter/block mount bolt, the POS on the solenoid as normal.  I do it this way because having the ground just bolt to the chassis means the engine ground for the dist is in the motor mounting system.  Paint, mud, rust, oil, and lots of other stuff can disrupt a good grounding surface.  So, by using the bolt on the block you ground the block directly, and the HEI housing is grounded by the hold-down clamp.  Make sure the clamp mount is clean and do not paint the clamp.  Chrome looks good, and in this case works better.  Also, make sure your in-line disconnect is the right size for the job.  The SUMMIT or SPEEDWAY offered race parts are perfect.
Will this fix your issue?  No idea.  But, if you do your power supply like this, when you push the starter button you are getting every drop the battery can offer.  I have had good luck with this system.

It is still possible that the sputter was not due to a lack of battery if it went on for a while and did not change or get worse as the race went on, and only happened at WOT durring high RPM.  Poor voltage "should" show itself under heavy load, and that "should" be under acceleration, or, if the battery was fading, the issue "should" have been worse as time went by, but I'm just guessing.    

I wasn't there to hear it, or see it, so these are flat guesses for possible issues for high-end sputter that is constant with RPM and throttle position are:
Cell pick-up not in the bottom/rear corner.
Fuel line sucking air/sucking shut between cell and pump.
Fuel cell vent not working.
Fuel pump has debris in it/not working correctly.
Fuel filter debris.
Air cleaner/air flow restricted
Debris in fuel bowl.
Metering plate ports/air vents plugged
Throttle shaft vacuum leak.
Tight valve lash
Loose valve lash
sloppy timing chain
cam walk due to no button on a solid cam
Bad valve spring(s)
Bad plug wire(s)

Another issue is possible timing/dist issues.  Bad timing can cause a consistant flutter.  If you are using an OEM harmonic balancer, you must be sure that the timing mark is correct and that the outter ring has not moved.  If you see more rubber bulging out fore or aft, then it may have moved(rotated) and that makes it pretty tuff to time correctly with a light.  Be sure the timing mark is correct.  Make sure the timing tab is correct too.  I know these are basic, but it they are not correct, you can't be sure of timing.  I run a 355 on gas at 33*-35* .... and I use two steps colder than stock performance plugs and 8mm wires.  All off an OEM style HEI, and spin 7,000 rpm without issue.

I run the timing advance plate locked at full advance.  I do this to avoid over-advance and timing bounce.  I wire the starter direct and the ignition on a switch.  This really is needed for starting a full advanced car, but also helps start a hot car, makes setting valves a little easier, stuff like that.  I would suggest running the plate locked, pinned, at full advance.  Fill the hole that is left from removing the air/vac can with some blue RTV.  Just a blob and let it set up, install the cap and that little plug should be good for keeping out debris.  You MUST cover the dist when pressure washing if you do not seal the cap properly.  I cover mine with a heavy plastic bag from the nut-bolt supply place.  Big, shallow, tuff, free.  Perfect.

Anyways, that's my $0.02


The sizing and design of the intake/carb/cam/ and such is very important, but it has been my experience that those issue are where you find power, response, and drivability more so than a sputter in a lower powered engine running down a short straightaway.  A flat cam, bad valve springs, sloppy timing chain and stuff like that are more likely than a bad air signal at the carb due to poor plenum/runner volume/valve opening in this application.  But, that too is just my best guess.  

Good luck