What can i do to make my 1966 do better than a 16 at LACR. it is a 300 deluxe post and i swaped the six cylinder with a 383 stroker w/ 10: 1 comp. a 650 speed demon carb, street dominator manifold, nitrous hp cam w/490 intake lift and 520 exhaust on stock heads with 2.02 valves and a muncie 4 speed. and to top it all off it has a 100 shot of nitrous. however it still has the stock 10 bolt rear end. what can i do, if anything, to improve my times

First thing you need to do is post your complete timeslip with 60 foot times, 660 foot times and speed, and 1/4 mile times and speed. This will help us see where the issues are.

im not sure of my 60 foot times or my 660 times . i do know that i ran 16.3 at 89 and the best i did was a 15.7{with nitrous} and i believe it was at about 91 mph

What gearing do you run? What was the launch like, lot's of tirespin?

Don't forget your quite higher than sea level at LACR, and maybe you are really being affected by your jetting and timimg because of that. your car sounds like 13's to me, off the bottle. You didn't mention rear gears..I know my Trans Am did terrible up there too.

Sorry if this sounds stupid, but, are you sure it's a 383? Who built the motor? If you built it, then you obviously know what you got, but if someone else built it, they could be/have told you that you got things that the motor doesn't really have.
Other then that, I feel your pain. My '71 ran a best of 8.80@79mph on the 1/8 mile and according to the charts I should be running a 13.73@99mph. I've seen and read about other's who have similar set ups, or even slightly "tamer" then my set up, and all of them are running faster times then me. What is the corrected time for your runs? I know that since LACR is a higher altitude, the times need to be adjusted so you can know what you'd run at sea level. What rear gears are you running? Are they stock gears? I think that carb is too small for you set up, I'm using a Holley 750VS with a cam that has .488" E/I without nitrous. Good luck, and I hope you get things runing good! :D graemlins/thumbsup.gif

I would do a compression test, check your timing, check your plugs, check to see if your carb is opening 100%. Are you getting enough fuel? Whats your fuel lines and fuel pump? Whats your exhaust (headers & pipes)? You should gain a lot more than 2 mph with a 100 pill of nitrous.

With a 4 speed your ET may never get where you want because launching and rowing the gears fast enough can be a bit tricky.

Stock heads blow, those will really hold the engine back. I recommend going with a quality aftermarket head and I think a Performer RPM Air-Gap intake would be better for the combo too, maybe with a spacer if your hood would clear it.

What gears?

Still, 89 or 91 mph from a 10:1 383 shows it as an underacheiver. For sure do a compression test, have a friend nail the throttle and see if the carb is opening up all the way ( 1st thing), timing, valve lash, etc.. I'm no pro at this, but if you can't run at 100 mph with nitrous, something is amiss.

The emotion you should be feeling alot of is pure intellectual curiosity!

SOunds like you;re running on alot less than a 4 bbl.

Find the timeslip,post the incrementals,then you'll get all the help you need,until then we are all :confused: like you.

Using wolfplace's formula..you are putting out 268HP(engine HP) Looks like you are leaving 50 or 60 HP on the table. I dont know what the elevation at LCDR is. The correction factor may put you at 300HP or so.

L.A.County Raceway is 2700 ft altitude

Here are my best guesses. Was the cam degreed upon installation? Check the valve lash, check the timing and carb tuneup. Make sure you have adequate fuel flow and pressure and that you are running on all 4 barrels. If everything checks out, you might have a single wheelie peelie airplane geared 10 bolt and you are burnin that one tire so far down the track that by the time it hooks to any degree, you dont have enough room left to come close to your cars potential. Thats why seeing your timeslip would help a great deal, cause it will show a lot about the cars track manners. And finally, this is the most simple one but also a very possible one, how is the clutch in that 4 speed? If you are burning off all your horsepower through the clutch, than that is a big portion of your problem. If you could tell me your tire height, your rear gearing, what 4 speed it is, and what gear you crossed the finish line in, and finally, your engine rpm through the traps(give the rpm for each different MPH of 89 and 91). With this I can tell you how close the number for your MPH is VS what it should be. If it ends up being way far off, theres a good possibility that your clutch needs a good lookin at. It could be a combination of about everything. Either way, if you arent sure about the tuneup(mainly timing, carb, and fuel flow & pressure), I wouldnt put it on the juice again until everything has been checked out cause nitrous running through a bad tuneup can cause a lot more problems than slow track times(you might one day find parts of your engine flying down the track faster than your car....no good).

It could be anything. We need that 1/4 mile slip and some details. Was it nosing over on top end? Bogging off the line? Popping in the upper RPM'S? Did you try to tune/change jets on the carb at all when you were there? Wheres you timing at? Does your carb open all the way up when you put it to the floor? You gotta give us something to go on here. Post everything you can even if you dont have the time slip.

LACR Generally has terrible air. Comman to be 4500' +.

Something is definetly wrong with your combo.

Back in 85 or so my stock bodied 66 Chevelle w/ stock rotating assembly, small erson, cam, headers and 4.10 gears ran 15.80's @ 86 MPH at LACR.

Wow, I could hang door-to-door with you with my stock 307! something definitely doesn't add up here.