I have a 67 dart 225cyl. bored .060 plained .030 and .115 cut off the head. The cam is a Comp Cam .490 lift 230 duration at .050 and 340 valve springs.
the valves are 1.78 intake 1.50 exaust . A 650cfm 4BBL carb with a 6 into 1 header. the car has a 904 trans. 2500 stall tork 4.56 gears and is only 2650 lbs.
So why is my ET. 15.2 and MPH 89.9????
What am i doing wrong.

I would be a fool to say I know anything about it, but I'll shoot out some ideas that you (or someone smarter than me) will most likely shoot down.

What type of ignition system are you using?
What is your timing curve like? Total timing?

What mods have you made to the carb to calibrate it to a more acceptable CFM range? I doubt that even a built /6 would use all 650cfm.

How well does it "hook up"? Is all that being lost at the starting line or does the motor just not pull like you'd expect?

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1980 Aspen 225 super six

As far as the engine goes - I would reccomend 3 things -

1 - Get .100" taken of the deck of the engine - you already have 30 - so maybe 60 - 70 more - you ar going to want to check the piston to valve clearance - Chek with a machine shop - or other good local source on this.

2- Get the head ported and polished - Thereis tons of power and speed in that head.

3 - centerline your cam.


Maybe you have done some of these - but you did not mention it in your post.

I was in a similar situation to you at the end of last year. I could only go 17.2 - I will not be able to see the results of my improvements until the summer -- but I did do those 3 things.

Any others Wishing to Chime In??

Lets help this guy out!!

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http://www.youtube.com/hyperpack

Yes and as Paul has stated ther is a myriad of things that could be going on with the:

1 - Carb tuning

2 - Rear Suspension

3 - Ignition / Ignition


These factors could play a role; I would check them out also if you havent already.


Greg

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http://www.youtube.com/hyperpack

You arent happy with 15.2@90mph in a 6cyl? you are putting 180hp to the ground out of an engine that only made 145 at the crank(about 90 to the ground) in stock form. you have doubled its out put.
you are not going to go much faster with out putting nitrus on that beast.

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I've run 15.9s in a 3200 lb car with 2.94 gears using that same cam and similar valves w/2800 converter.

With a car that light, and that cam/head/etc combo, you should be able to run 14s or even high 13s. These guys have covered some big points above. Cam timing and ign timing are crucial. Carb tuning will be a biggy too. Head porting can also help a lot.

I have seen 0.5-1 sec improvements just by adjusting (retarding mostly) timing advance. Do not exceed 30 deg total (mech only) advance. 28 deg is probably better for the MPH. Vac advance does not matter, but disconnect to map your timing curve. If you don't want to map it, just spend a day/afternoon at the track and just back off timing w/o changing anything else. You might be surprised.

I would also run a higher stall converter - 3000 rpm at least (9.5-10" or smaller).

Lou

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Home of Slant6-powered fun machines since 1988

definitely port the head.... attention to the bowl area is A+, make the bowls nice and shape them good to match the big valves you have

Thanks everyone for the replys. I will try to clear up a few points.
I have a mopar per. ignition control unit, kem high per. plug wires
accel super coil ,recurve dis. at @ 32 total timeing.
the 15.2 run was on stock trans. except converter and stock suspension
60' ranged from 2.32 to 2.59 .I do not know much about carbs. but i tryed
a 390cfm and a 500cfm. The mph and et went to 16.1 to 16.9
There is not alot of help here because it is only 2 slant 6 cars that i have seen at the track. Mine and the 72 duster with the blower.
Ihave changed the suspension to a 4 link,rebuilt the trans. useing a lower first gear and more clutch plates. Do you think this will help?

Sorry I forgot to say that the head was ported and polished. Also I have a Edelbrock nitros kit
that's not on the car yet.
The nitros kit range from 100-250. How much will my little slant 6 take?

Russ.

Wow, your 60' times suck as bad as mine! (not an insult, trying to help ). Difference is, I'm running a 3.23 (albiet with a low first gear). I have yet to do anything to improve mine, but after talking with the more experienced /6 racers here, I think a higher stall T/C will cure what ails mine (and some spark timing curve tweaking, perhaps). My car with a Comp 264 cam has run best of 15.58, my best 60' has been 2.34 sec. The T/C is a TCI "breakaway" I think it was rated 2500 to 2800 (but of course it doesn't stall that high behind the /6). It launches about like a stock 318 2V with a 2.76 would, then maybe 100 feet out, it starts to pull like a turbo is kicking in or something! My next move is to go to a 10" converter.

D/W

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If it ain't broke, fix it!

You should be in the 2.1-2.3 60ft range at least. Converter stall will help more overall than a lower 1st gear because of 1-2 gear splits.

32 deg total is too much advance. I don't think any of the racers run more than 30. 28 is probably more typical. Curve could be costing you on the low end.

Slant should take at least 100 hp shot, IF you don't get into detonation.

Lou

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Home of Slant6-powered fun machines since 1988

When the drag track open's in June,I will try the things that was said and along with some of the changes I made we will see if the car will come into the 14 range. I will come back and let ya know how it ran with and without the nitrous

Russ Thanks.

i would say the carb is too much i had a carter 500 off my
dad's hemi that wat built and i bought a 500 cfm Edelbrock
from summit and ran 2 tenths faster but that is my car i
would not recomind going out and sping 200 or a carb i
would see if a friend would let you use theres if
they have one hope you find out what is wrong

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http://www.geocities.com/slantisxduster
http://www.mattcrane.net

well i dont know what the problem is like i said it helped me but i have a different combination and a streeable daily driver running 10's in the eighth so i don't know what it is but hope you find out

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http://www.geocities.com/slantisxduster
http://www.mattcrane.net

How do I post A pitcure of my car [/img] Russ.