You tell me is a 4:10 gear to low for a 3 speed turbo 400 or 373s better . - Team Camaro Tech
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post #1 of 23 (permalink) Old Mar 11th, 01, 08:44 PM Thread Starter
 
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well have a 79 camaro it has a 400 small block in it and right now it has 4:10s but when i raced it this weekend it only ran a 14.30 but i shift every gear around 5200 to 5300 and when i cross the finish line im running 5000 do u think this is ok kinda feels like it starts losing power that high in rpm range but we started putting 3:73s in today do u think these will help me or hurt me i think with them gears i will be running 4000 crossing the line . but here is what my car has . it is a 400 sb with rpm performer intake , 750 holley , holley fuel pump , headers, bored 30 over stock dish pistons , 2.02 heads, 3000 stall and a turbo 400 with trans pack and of course 4.10s but getting rid of them dont yall think my car should be running better than it is, my car wieghs 3,640 with me in it im guessing
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post #2 of 23 (permalink) Old Mar 12th, 01, 04:50 AM
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what kind of cam you running?
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post #3 of 23 (permalink) Old Mar 12th, 01, 11:18 AM
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What cam and heads are you running? 2.02 heads could be a hundred different ones.

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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
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post #4 of 23 (permalink) Old Mar 12th, 01, 11:57 AM
 
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by the RPM's, I'd stick with the 4.10's.


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383 Speed-O-Motive stroker kit with Speed Demon 750, RPM intake,Proform HEI dist.MSD6a box,World Products Sportsman II heads, ported and polished with 2.02/1.60 valves,64cc,TRW forged pistons with 10.7:1 compression, Comp Xtreme 284 cam,Crane pushrods, Comp Cam 1.6 full roller rockers,ATI damper, 40 series Flowmasters, 4.11 gears with TH350 and 3000 stall.Powertrax NoSlip Locker
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post #5 of 23 (permalink) Old Mar 12th, 01, 12:12 PM Thread Starter
 
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490 lift comp cam and 2.02 heads not sure which ones but my car feels like it is topping out, and this is also a street car
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post #6 of 23 (permalink) Old Mar 12th, 01, 01:00 PM
 
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Check fuel pressure at WOT and have you done anything to the ignition? I know stock HEI's poop out at like 4500-5000 rpms. So maybe a better coil and module might help.

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383 Speed-O-Motive stroker kit with Speed Demon 750, RPM intake,Proform HEI dist.MSD6a box,World Products Sportsman II heads, ported and polished with 2.02/1.60 valves,64cc,TRW forged pistons with 10.7:1 compression, Comp Xtreme 284 cam,Crane pushrods, Comp Cam 1.6 full roller rockers,ATI damper, 40 series Flowmasters, 4.11 gears with TH350 and 3000 stall.Powertrax NoSlip Locker
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post #7 of 23 (permalink) Old Mar 12th, 01, 01:05 PM Thread Starter
 
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yeh stock hei ignition
how much does a DUI distirbutor usually knock off?
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post #8 of 23 (permalink) Old Mar 12th, 01, 01:11 PM Thread Starter
 
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i think my heads are 76 cc chambers but ok heres the deal last year i ran a 14.49 then we took out the turbo 350 and torqe converter and put 2.02 1.60 heads , roller rockers , turbo 400 with transpack , and a 3000 stall before my 2.02 heads i had 1.94 1.50 valve size and last weekend when i raced it it only ran 14.30s not much better than before its wierd though my 1/8 mile is 9.1 and at 75 and last year it was 9.3 at 76 slower mph but better time i also had the 4.10s last year when i ran the 14.49 but even with the 4.10s and every thing we put on it , it only runs 1 tenth faster something is wrong we are going to finish puttin in the 3.73s today but last year before the rear end i had a 3.42 rear end and was running 14.56 and after the 4.10s the best i ever got was 14.49 shouldnt gears knock off more than that and after all the stuff we done this year only runs 14.30 at 95 mph this sucks
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post #9 of 23 (permalink) Old Mar 13th, 01, 12:24 AM
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Since it sounds like you want to do a lot of drag racing with this car I would leave the 4.10's in there. I see a couple of problems with your combo...if those are indeed 76cc heads then your compression will be arount 8-8.5-1...not enough for the cam you are running (it was a comp cams 286 magnum, wasnt it?)...this will make the low end a little weak, but it should run good above 2500 rpm or so. With the low compression, you may need to run as much as 16 degrees initial timing but try and have the full mechanical advance in by 2800 rpm or so...and most 400's do not like over 34 degrees total timing. In your case it probably wouldnt ping but you could still be losing power. Is the car spinning out of the hole? If you are getting more tire spin now than with your old setup then that only hurts the times. Many 76cc heads show very little (if any) flow improvement over stock 1.94's...in my opinion (for what its worth) the head swap probably wasnt worth it...unless the old heads were shot. You would be better off getting a set of 64-68cc heads and get the compression up...strap on a set of trick flows and you could gain 60-70 hp. Dont get discouraged though...with some tuning you should still be able to get into the 14.0's if not a little quicker. Play with the timing, secondary springs, jetting, launch rpms, etc...it is very rare for a car to run its best without a bit of tuning.

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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
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post #10 of 23 (permalink) Old Mar 13th, 01, 06:09 AM
 
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Another thing, on the DUI HEI's, be ready to spend over $300. I would just get a better coil and module like from MSD to put on your HEI. No need for a whole new distributor, just freshening.

I would keep the 4.10's. You have decent RPM's crossing at the big end of the track, going to 3.73's will only hurt that.

I totally agree with Travis.
Change the heads to a good 64cc head, and mess with the timing and carb, and you could be seeing low 14's if not high 13's soon.

Keep us informed!

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383 Speed-O-Motive stroker kit with Speed Demon 750, RPM intake,Proform HEI dist.MSD6a box,World Products Sportsman II heads, ported and polished with 2.02/1.60 valves,64cc,TRW forged pistons with 10.7:1 compression, Comp Xtreme 284 cam,Crane pushrods, Comp Cam 1.6 full roller rockers,ATI damper, 40 series Flowmasters, 4.11 gears with TH350 and 3000 stall.Powertrax NoSlip Locker

[This message has been edited by Tracy Focht (edited 03-13-2001).]
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post #11 of 23 (permalink) Old Mar 13th, 01, 11:31 AM Thread Starter
 
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no i wasnt spinning out at all the track was real sticky my 60ft was 2.0019 thats my best so far but i have a 1 inch spacer under my carb so if i take that off i think i might be able to get a 1.9 , o hope to run a 14.00 flat or something but so far my best is 14.36 at 94 mph thats y i think its slowing me down car starts to shake and berly pick up mph around the end so hopefully the 3.73s will help me by giving me a few more mph , see last year with the stock heads i was spinning first gear and still running a 14.49 but this year didnt spin at all and only ran a little better but the track was sticker this time,, so what do u think i would run with trick flow aluminium heads if i can get my car down to a 14.00 yall think i would run a 13.50 or something like that.
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post #12 of 23 (permalink) Old Mar 13th, 01, 11:52 AM
 
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If you car isn't revving at the big end, the gears will hurt you. You need to find out why it's not pulling to at least 6000. Look at the fuel pressure or ignition. The 3.73's will hurt your ET if you are going thru the big end at 4000rpms. You want to be in your torque and HP range.
Keep the 4.10's and find the other problems.
Changing the heads will help too.

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383 Speed-O-Motive stroker kit with Speed Demon 750, RPM intake,Proform HEI dist.MSD6a box,World Products Sportsman II heads, ported and polished with 2.02/1.60 valves,64cc,TRW forged pistons with 10.7:1 compression, Comp Xtreme 284 cam,Crane pushrods, Comp Cam 1.6 full roller rockers,ATI damper, 40 series Flowmasters, 4.11 gears with TH350 and 3000 stall.Powertrax NoSlip Locker
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post #13 of 23 (permalink) Old Mar 13th, 01, 07:58 PM Thread Starter
 
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well see before the 4:10s i had 3:42 gears with that gear ration i could rev 6000 almost but after the rearend swap i couldnt rev as much and the gears were real short so i dont know it think these gears will help me cause ill be able to turn more rpms , cause after the 4:10s i could only rev 5300 or 5400 i have a holley mechanical fuel pump and a 750 holley secondary the new kind , so do yall think with a dui distributor i could rev more rpms? cause my dads friend will sell me one for 65 bucks.
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post #14 of 23 (permalink) Old Mar 14th, 01, 05:24 AM
 
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If it's complete for $65.00, get it. But something is keeping you from revving to the old rpms. See if you are going through the lights at 4000 rpms, you need that. 3.73's will lower that.
Try adding the new distributor and see what happens.

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383 Speed-O-Motive stroker kit with Speed Demon 750, RPM intake,Proform HEI dist.MSD6a box,World Products Sportsman II heads, ported and polished with 2.02/1.60 valves,64cc,TRW forged pistons with 10.7:1 compression, Comp Xtreme 284 cam,Crane pushrods, Comp Cam 1.6 full roller rockers,ATI damper, 40 series Flowmasters, 4.11 gears with TH350 and 3000 stall.Powertrax NoSlip Locker
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post #15 of 23 (permalink) Old Mar 14th, 01, 08:25 AM
 
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hey 79 tx I was running a 13.3 at 105 mph with 4:10 gears I had a mild 350 it had 1965 202 heads and single plane intake(torker 2)my cam was 566lift and 288 duration nothing to wild but very strong.keep the 4:10 and work on the motor.I was shifting a 6500 and I also ran a 750 holly. good luck
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