What RPM going through the traps with a 408?

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pettybludart

pettybludart

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I,m having a hard time in my search for 10,s with my 408(410).My best runs have been 11.20@118 with MT DR 26 inch and a 3.91 gear.(going through the traps @6600-6800rpm)I now have 4.30 with spool and lastnight ran some older 28 inch Hoosier slicks,going through the traps @6800-7000.I have a 7000 chip with MSD 6AL.My Coan 8 inch 4500 stall is working good(lastnights 60fts were 1.56)Will new slicks help my 60fts?What RPM will these strokers top out at RPM wise?I,m making all my HP around 5700rpm so would it be worth it to get a 7500 chip and go back to the 26 inch tires(will I runout of steam?)All I want is a 10.9!LOL.Lastnight some people telling me my car left hard off the line,then my buddys wife and another friend said my car spun off the line?I,m debating some new 325/50/15 MT DR(I do take the car to a couple car shows per year)Any help/advise will be appreaciated.Thanks

P.S Should I try a 1 inch carb spacer also?
 
Man we think alot alike ,as i just added a 1 inch spacer and jetted up my 408 for the same reason.Only difference is im only in the 11.40's.I am running 4.10's in the 1/4 with a 26 tall slick and im going through the lights at 6200-6300 at 113.5 mph.My stroker seems to fall off after about 5800 rpm sharply (i dont have enough cam).On the other hand im in the the mid 7.2's in the 1/8 with the 4.86 gears.I havent ran it in the 1/4 since the spacer and jett upgrade ,but im thinking it should go a real high 11.3 or real low 11.4 in the 1/4 now when i switch the gears back to the 4.10's.I wont know for a few months though.I can tell you that the spacer and jett change moved the powerband up a few 100 rpms in the 1/8.It used to break up in the lights at 6200 ,but the spacer and jetts fixed it .I want to run 10's bad also .My major obsticle is the Powerglide trans.I want to keep it because its built and has a Tbrake and a pricey convertor ,plus its holding up well to my low 1.5 60 foots.It needs 3.91's in the 1/4 IMO ,but it will cost me 60' with the high ratio first gear it has.My 408 is only 10 to 1 and has a hydraulic .484 /235 duration cam in it with a 750 Demon.Your closer to the 10's than i am for what its worth ...
 
Hey Shocker,what size/brand of tire are you running?My compression is 10.5 to 1 with a solid roller .631 lift 252@258 @106.I,m gonna try with the 26 inch again and get the 1 inch spacer.I haven,t tried jetting yet as it,s a new AED850HO(apparently flows 930CFM)I,m also running advanced at 36 total.Guess I,m gonna have to play with it this coming saturday,would like to run a couple tenths faster before PINKS at the end of the month.
 
What is the mph with the 28" tires and 4.30s? What heads were on it again? I'm showing something around 5-6% slippage on that convertor which is about normal but could be tightened later. What was the dyno curve from 5K to 6K?
 
My slicks are 26/8.5/15 M/T Et Drags and im running them on 7 inch wide steel wheels with no tubes.I have had the best 60 foots with 15 psi in them.14 or 16 psi doesnt seem to work as well with my cheapo setup .Im tempted to stick a 100 shot of spray on it and be deep in the 10's ,but i want to do it with just motor ,just so i can say i did it with a 10 to 1 all motored small block.When this motor need freshened up (if it ever does since i dont run it much) im gunna do sum head porting ,more cam ,and carb ,but i just cant bring myself to tear down a healthy motor thats stayed together for over 120 passes and running faster all the time.Mines just a Nostalgia event racer that is not street driven.Its only raced about 6 or 8 times a year at rare 64 and older events,so it may never wear out ,lol...
 
pettybludart said:
Hey Shocker,what size/brand of tire are you running?My compression is 10.5 to 1 with a solid roller .631 lift 252@258 @106.I,m gonna try with the 26 inch again and get the 1 inch spacer.I haven,t tried jetting yet as it,s a new AED850HO(apparently flows 930CFM)I,m also running advanced at 36 total.Guess I,m gonna have to play with it this coming saturday,would like to run a couple tenths faster before PINKS at the end of the month.
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Hey Scott sorry to but in,have you used a octane boost before? if so which one. Thanks, Craig..
 
CRAIG COX said:
Hey Scott sorry to but in,have you used a octane boost before? if so which one. Thanks, Craig..
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No Craig I haven,t used any octane boost,just 94 octane gas.Moper,I didn,t have it dynoed,but had my other motor(small stroked 340to 372)dynoed and it made 452hp@5700 so am kinda going by that dyno run.My heads are Eddy RPM,s with a mild P&P.I ran 11.32@116 with the 28,s and 4.30,s.
 
My next time to the track,I,ll have to check my timing to see if it,s too far advanced.I haven,t touched it and have made over 30 passes.:read2:
 
i would try retarding the timming back to 32-34.put a white stripe on 1 tire and have someone watch the stripe on take off to see if you have a lot or a little tire spin. my 2 cents
 
With that cam your running you should already be well into the 10's..when i first put my 416 together i was running a .494/.513 hyd. cam and was in the 11.20's...with 3.91's..something is deffinately off with your combination..
 
35regal said:
i would try retarding the timming back to 32-34.put a white stripe on 1 tire and have someone watch the stripe on take off to see if you have a lot or a little tire spin. my 2 cents
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This....but instead, get someone to video the tire with the stripe. that way, you can go back and slow it down so you can really see the tire spin.
 
Well I guess I,m just gonna have to play it by ear with some more T&T.The engine is running great and the car has been very consistant,outta 35 passes they,ve all been 11.2-11.3 @ 116 or 118mph.Will try backing off the timing just to see what it does?Will also try a run without the chip in the MSD box and will also try the 26 inch tires again for more MPH.:clock:

Thanks for all the advise/ideas guys.
 
I'd check timing, fuel pump (the car might have a slight stumble that would cost you some time, higher volume pump) and run new 28" slicks. You could be spining the slicks on the rims.. Sounds weird but you can do it. You could try to drill and tap screws into the rims and slicks to prevent the rims spinning in the tires. The screws are found at most performance shops (summit) I used some (moroso) on a duster with widened rallie wheels and they worked great and the car hooked up alot better. I used the painted stripe idea on the tires and was amazed how much the rims spun inside the tires before I had screws in them. Hot rod Magazine had a writeup about this idea. Timing and maybe rejet the carb? I think you have air shocks in the rear, adjust the pressure to put more weight on the rear of the car...might help to pop those front wheels up...good luck
 
Having fun yet? Good headers help air flow. You need 1 7/8" tubes. Your combination should be running 120+. I just ran @ Martin US 131.(Chrysler Classic) I went down to the quarter finals in the Pro class! Best pass was a 10.07 @ 131 & change in the "heat" and I mean heat! I have turned in a 9.98 pass this season @ Milan Dragway in Mid June. Car weight is 3055 with driver. Keep working your combination, you'll get the elusive 10 second pass soon!
 
Rob Eppler said:
Having fun yet? Good headers help air flow. You need 1 7/8" tubes. Your combination should be running 120+. I just ran @ Martin US 131.(Chrysler Classic) I went down to the quarter finals in the Pro class! Best pass was a 10.07 @ 131 & change in the "heat" and I mean heat! I have turned in a 9.98 pass this season @ Milan Dragway in Mid June. Car weight is 3055 with driver. Keep working your combination, you'll get the elusive 10 second pass soon!
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Hey Rob,long time no chat.How,s your summer going?I,m running 1 7/8 tube Hedman Huslers now.My 2nd run ever was 11.32@120mph,then ran 11.20@118mph at Grand Bend a month ago.Going to ArmDropLive tomorrow night for the weekend.Hope I can get me a 10 ?LOL.Maybe $10K JK.:cheers:

PS 60fts have been 1.57 Hey I,m working on it!
 
Mmmmmm…I trap ~6800 with mine (4.10 gear w/ 28” tire) in the ¼, but I run 1/8 mile most of the time. You have a little bigger cam than me and a bigger carb (the rest is about the same), but you’re a little slower…Have you spent much time tuning the carb? If not, there is probably a tenth or 2 right there.

Good luck with the 10 second hunt. I got mine to run 6.93 this spring in the cool air, but in the heat it runs 7.08 most of the time.
 
you might get more out of you car if you go with a 3.73 gear pull your engin back into its power band if you can run the 26 or 28 and see how you do just wondering how many pony you got but more intrested in the torque the monster makes and what stall you running could be too tall and you will lose time hope this helps
 
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