Too much gear?

Posted By: 76318dart

Too much gear? - 03/31/12 05:27 AM

Okay I have a couple of questions. First heres my combo:
340 with 4inch stroker crank
10:5 compression
571/571 248/254 hyd roller
Rhs heads 2.02/1.625
air gap intake
pro systems carb 830cfm
904 with a turbo action 10in
410 gears.
okay well i got it to run a 11.60 @ 113. It seems like it is falling on its face after the 1/8 mile.
my 60ft is a 1.56 and my 1/8 is 7.30 at 92. I run a 27 in tall tire. it just seems like I have too much gear, because i shift it at 6500 and go through the traps at 6400, but anything over 6200 it seems to loose power so what gears would you recomend for it? or what else would you change? I am running a mechanical fuel pump a 120 gph carter.I have msd 6al and distrubtor.thanks for looking. just need some ideas

Posted By: dartman366

Re: Too much gear? - 03/31/12 05:51 AM

what you got for a fuel system? may be running out of fuel.

Posted By: 493_DART

Re: Too much gear? - 03/31/12 09:25 AM

next time out try shifting at 5800 , then next pass 6000 . See what it does

Posted By: smokinwoody

Re: Too much gear? - 03/31/12 10:28 AM

what size chip/limiter is in the ignition..

what does the plugs look like..

how much timing...

may also want to switch to a 28" tall tire...

Posted By: 76318dart

Re: Too much gear? - 03/31/12 11:24 AM

im running 3/8 fuel line with carter mechanical and my chip is a 6800. and my timing is set at 38 total and i have done 36 with no difference. I was thinking 28 in tall tire just have to cut to make room for that size lol.

Posted By: Coldart

Re: Too much gear? - 03/31/12 12:24 PM

w/cam you got - motors probably done @5500rpm or less.
w/4" arm need more duration for more rpms.
numbers are about right for your combo.
Taller gears.

Posted By: 76318dart

Re: Too much gear? - 03/31/12 12:53 PM

Okay thanks. What gears you thinking?

Posted By: DragDart360

Re: Too much gear? - 03/31/12 01:39 PM

How heavy is your car? I think your gearing is OK, Changing to 3.91 would not make much difference. A 29 tall tire would be your best bet.
What converter stall and how much slip?

Posted By: 440Jim

Re: Too much gear? - 03/31/12 01:39 PM

Quote:

410 gears.
okay well i got it to run a 11.60 @ 113.
I run a 27 in tall tire. it just seems like I have too much gear, because i shift it at 6500 and go through the traps at 6400...

Looks like 10-11 percent converter slip at the finish line. That is too much IMO. If you get a converter with 6 percent slip, the trap RPM would only be 6100 rpm.

If you can get a 28" tall tire in there, that would help about 200 rpm.
With the small cam duration,limited head flow and hydraulic cam, it might not like too far over 6000 rpm. What valve spring pressures (seat and open) do you have? Too little will kill higher rpm power.

Posted By: 76318dart

Re: Too much gear? - 03/31/12 02:06 PM

My car weighs 3250 w/me. the converter stalls around 3800. And im not sure about my springs I know they are comp behive springs. And might be installed at 1.81? Im at work ill have to look when I get home.

Posted By: DragDart360

Re: Too much gear? - 03/31/12 02:35 PM

I've heard strokers don't like as much timing as the 340/360. I have mine at 32, I haven't messed with it since I installed the engine, Just working on the rest of the combo.

Posted By: slippery440

Re: Too much gear? - 03/31/12 02:56 PM

I would check fuel system and valve springs. My thought is 4.10 gear is not the problem. The 60' is slow and with 3.91s it may get worst. Car should go alot faster.

Posted By: dartman366

Re: Too much gear? - 03/31/12 03:12 PM

my 408 likes 32-33 degrees of total timing, I still think you are running out of fuel, a 3/8 line and a carter pump to me isn't suffecient, I know mine likes to eat, I really don't think your gearing is off that far, alot of other factors play into the whole combination, like cam,springs timing, cam centerline, fuel delivery etc.

Posted By: 440Jim

Re: Too much gear? - 03/31/12 03:18 PM

Quote:

And im not sure about my springs I know they are comp behive springs.

The correct Comp Beehive springs should be good, if installed at the correct height.

Posted By: MR_P_BODY

Re: Too much gear? - 03/31/12 03:35 PM

I dont think its the gear either... as said... check
your fuel supply... also with the timing set it at
the minimum that it doesnt slow down not the max...
what is the cam installed at(did you degree it)

Posted By: 76318dart

Re: Too much gear? - 03/31/12 03:41 PM

Okay I was thinking of upgrading my fuel system. My cam was installed at 108 or 107 if i remember correctly and it was degreed.

Posted By: RUNCHARGER

Re: Too much gear? - 03/31/12 04:10 PM

Mount a fuel gauge on the cowl to be sure.

Sheldon

Posted By: mopardamo

Re: Too much gear? - 03/31/12 04:19 PM

Hello,

Check/upgrade the needle and seat size in the carb too.

Damon

Posted By: Cab_Burge

Re: Too much gear? - 04/01/12 03:16 AM

One sure way to check your fuel system s o jet the carb up several jets sizs at the track and see if goes faster or slower on the 1/4 MPH, if it doesn't change you probally have a fuel delivery VOLUME problem

One other thing IO would try is to back the timing down to 32 to 33 degrees total(above 4500 RPM

)Let us know what you find

Posted By: HotRodDave

Re: Too much gear? - 04/01/12 04:38 PM

Those heads have really efficent combustion chambers and do not need as much timing as old fashioned open chamber SB heads, bump the timing down to 32 or so total.

Also need to upgrade the fuel system

Posted By: DUSTERB'D

Re: Too much gear? - 04/02/12 02:46 PM

I have a 416 stoker in my 3000lb. Duster,I run 28X11.5 tires, 4.30 gears, 32 degrees of timing, 1/2 inch fuel line with a Holley blue pump,RPM Airgap intake, 750 DP Holley,ported J heads with 2.02 valves,solid lift custom cam, 10 inch Turbo Action converter, the coverter is a little loose on the top end but it works OK, I shift @ 6500 and run 6700 thru traps,it runs 10.90's all day and 10.80's in good weather.

Posted By: 76318dart

Re: Too much gear? - 04/10/12 02:20 AM

Okay thanks.Im going to back the timing off then upgrade my fuel system and let you guys know.