Drag racing total timing,Eddy heads

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Marky Dart

Marky Dart

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Just thought I'd post this question on the RPM heads .I've built a 0.60 360 with SRP pistons down 0.20 thou.( I know should be at least a zero deck height)Comp Extreme solid flat tappit#231-4.Holley 850,Airgap,Hooker comp headers,TCI streetfighter 3000 stall.727-4:10's.Cranking compression with this cam is a dismal 180 psi.(stone cold).Drag radials and slapper bars and home made leaf spring clamps.comp Eng.shocks.Im racing this weekend with total set at 38.Now when I ran a sbc 383 with vic.Jr, heads I ran a 40 degree total.I know a different animal but curious to hear what others are running with these rpm heads.Car is a 70 Dart by the way.Oh and has 7.5" of vacuum idle in gear.
 
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I don't know if this helps or not, BUT, we're kinda in the almost same boat, your boat is up the food chain a little farther, and bigger, the block etc....
I run-and this might be different for you-NO vacuum advance, no crossover-X pipe on 3" dual exhaust and a Edlebrock™ 650 intake and RPM™ heads.
I'd love to dig through your "I thought it might work but..." parts pile.
Total of 38 seems right from what I remember from a 360 Duster I had, and this was in the early '80s and there was nobody to ask except that old drag racer next door, who you don't ask when he's sober-Lloyd. Thats a whole story in it's self....
Yeah.
I wrote stuff down with pencil and paper, it weathered 36 years and I can't find most of it but I still had that. The 318 I have so I hope that might help also.
If you don't mind a little backfiring you could try that 1 degree from where your at. And you probably already done that........(I'm gonna follow along to see how things worked out).
Oh, it's a '75 Dart Sport, 318, A 904, and 8 ¼ rear end, Hedman™ long hedders empty Flowmasters™, Edlebrock™ 650, intake and heads are Performer RPM™, MSD™ ignition, and is about 1500 miles from the rebuild.

318 Spec Sheet.jpeg
 
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Christine&Rusty said:
I don't know if this helps or not, BUT, we're kinda in the almost same boat, your boat is up the food chain a little farther, the block etc....
I run-and this might be different for you-NO vacuum advance, no cross over-X pipe on 3" dual exhaust and a Edlebrock 650 intake and RPM heads.
I'd love to dig through your "I thought it might work but..." pile.
Total of 38 seems right from what I remember from a 369 Duster I had, and this was in the early '80s and there was nobody to ask except that old drag racer, who you don't ask when he's sober-Lloyd.
Yeah.
I wrote stuff down with pencil and paper, it weathered 36 years and I can't find most of it but I still had that. The 318 I have so I hope that might help also.
If you don't mind a little backfiring you could try that 1 degree from where your at. And you probably already done that........(I'm gonna follow along to see how things worked out).

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Timing sounds ok but I would trash the slapper bars and unclamp the back half of the springs and let the suspension do it's job. I would run a pinion snubber about 3/4" from the floor. just my opinion.
 
Thanks for the reply.When I built the Chev 383 I used a similar solid cam-lift and duration with 10-1 compression.Apples to oranges again.The chamber design of the Vic .JR heads sure liked a lot of advance.It picked up big at 40 degrees and met another racer that ran 45 total with those heads.
I don't know enough about theMopar small block 340 RPM chamber design,especially with lower compression.My buddy runs a b.b. 440 with Eddy heads and runs 40 degrees.I guess i will make a few runs and try somethingI'll be lucky to get 3 or 4 runs in as it's probably the last race of the year.I will try running my Proform 750 after a couple passes with my 850.The 850 sure feels stronger street mid range but thats moot.
 
RAT ROD AL said:
Timing sounds ok but I would trash the slapper bars and unclamp the back half of the springs and let the suspension do it's job. I would run a pinion snubber about 3/4" from the floor. just my opinion.
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The back of the leafs are not clamped.The slapper bars do work.There is no real room for a pinion snubber.I mini tubbed the back.With a 275 in there and the front bracket in the middle hole there is about 4 " room.I can't justify $ Cal Tracs yet.Not up north with our exchange rate.Maybe next year.Some Mopar fellows are running slappers at the track pulling the fronts so they can work.
 
xLURKxDOGx said:
Never get tired of seeing those pictures, more, more, more!!!!!

Jake-non gold member
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My wife is coming to the track this Friday to take some pics.I'll post my experience and hope the wife gets some good shots.Hope to run high low 12's-High 11's.Its a daily driver pump gas project.3460 with my old butt onboard.Weather looks great-A little cool and sunny.
 
32-34 degrees with my eddies.
Have no idea how fast your wanting to go, but an 8 inch convertor will make a huge difference, and its extremely likely either a 750 or 950 carb will work better than the 850 will.
Good luck
 
B3422w5 said:
32-34 degrees with my eddies.
Have no idea how fast your wanting to go, but an 8 inch convertor will make a huge difference, and its extremely likely either a 750 or 950 carb will work better than the 850 will.
Good luck
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Yes a smaller converter would be nice but with 3000 stall and 4'10s now its at it's edge as I drive it just about everyday.Sometimes for miles.I will back it down to 34 and try that.Wish i had more track time but winter is a comin' and thats it for this year.
 
Marky Dart said:
Yes a smaller converter would be nice but with 3000 stall and 4'10s now its at it's edge as I drive it just about everyday.Sometimes for miles.I will back it down to 34 and try that.Wish i had more track time but winter is a comin' and thats it for this year.
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A good tight 8 inch will actually drive better than those sloppy 10 inchers do that are usually less effecient. No kidding.... lol
And the performace difference is astounding
 
I love my 9.5 ptc on the street. 4.10 gear 26.5 tire stalls 3400ish. About 6% slippage at the stripe.
 
I'd start around 34 total. Run it. See MPH. Add 1-2* run again see MPH. Up the engine likes it, down, wrong direction.

Having the initial correct will help with idle quality and snappiness off idle.
 
crackedback said:
I'd start around 34 total. Run it. See MPH. Add 1-2* run again see MPH. Up the engine likes it, down, wrong direction.

Having the initial correct will help with idle quality and snappiness off idle.
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Thanks Crackedback.I just finished setting up timing-34 total with 24 initial.I'm using a 4 seconds flat bushing.-Hey I also have a cracked lower verta-disc.
thank God for good Scotch.
 
360 , zero deck and 61 cc eddies, it doesn't like any more than 28*, your setup probably wont need to go back that far though.
 
raymond said:
360 , zero deck and 61 cc eddies, it doesn't like any more than 28*, your setup probably wont need to go back that far though.
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Good morning Raymond.As stated the pistons are below deck 0.20 and I believe the 340 eddies are a 65 cc.Cranking compression is 180.That I would think can be related to a big cam and pistons down the hole. Not sure about the 28?
 
crackedback said:
I'd start around 34 total. Run it. See MPH. Add 1-2* run again see MPH. Up the engine likes it, down, wrong direction.

Having the initial correct will help with idle quality and snappiness off idle.
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Just what I had in mind while reading through the post.
I was going to say start at 35*, and go in 2* increments and see how the car responds. Let the car decide where it wants to run. I would first go to 37*, and if worse, try 33*. Keep going till the car is happy
 
My butt-dyno, on the street, cannot tell the difference between 32* and 36*; so it's been at 32/34* since about 2004. She did the 1/8th at 93mph at that setting, and burning 87E10.
 
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