408/ 904 trans

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flyfish said:
My Caltrac's took me the better part of a race season to sort out, but now that I did I wouldn't change it. They are super consistent now, even in hot greasy conditions...but I foot brake....most of the folks I have heard that are having issues use a T-brake.
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Do you use a Transbrake?
Nevermind I see you footbrake
I feel like they will work even with the. Transbrake and a low first gear but will probably have to buy a good pair of shocks
Or look like a dumbass with the funky bunny hop thing. Which comes from the crappy instant center
And i also feel after all the money spent I could have just went with a four link and been miles ahead
 
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also just to state my experience
With Caltrac’s and using the foot brake
With the old engine I install the Caltrac’s complete system made a few motor passes
Then installed a 150 plate kit and sprayed out of the hole with out any trouble
Yep the Transbrake is when the trouble starts
 
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skrews said:
My point is when you look at the thrust vector in the chassis its all wrong because of the instant center is well above the center of gravity of the car. This makes the car more sensitive to track conditions. As you pointed out more guys have problems with caltrac A bodies than any other suspension, thats the reason. The Chevy and Ford cars have 25+ inch long front spring segments (which puts the instant center in a far better location in the car) as opposed to the 20" Mopar, and thats why those car work well with Caltracs.
I'm looking at going back to SS type springs next year, I've had enough of the Caltrac KoolAid
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I believe the instant center on a leaf spring car is the front spring eye. I think you are ref to the relationship of the instant center to the neutral line. Whether it will squat or rise.
 
W2 headed 408
904 low gearset with a brake
I believe he is using a 4.30 gear and a 275 drag radial
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I have been using the 904/2.74 gear set for 25+ years. Yes I have a big tire car, but not always was this the case. The low gear set always 60' faster and the ET was always quicker than the 2.45 gear set. I have two identically prepared 904 transmissions. One with the 2.45 gear set and the other with the 2.74 gear set. The 2.45 trans was slower. Valve body was used from trans to trans. I still use the 2.74 trans even with the current engine package. I like the way the car leaves! If traction is an issue, learn the track and shock settings...this can help a lot. My car is a ladder bar car with double adjustable front & rear shocks. It has taken time, but I have a good handle on this car. It is a winner...when I am any good! LOL. Just this fall, I did install an air shifter because the 1-2 shift DOES come quick! Sixty foot times range from a quick of 1.25-1.26 to a slow of 1.28-1.29. It is true, the 60' does dictate the overall ET. Lose it in 60' and the ET will show it all the way down the track! Again just my opinion as well as the others. We all have justifiable points! Jump off the porch and enjoy your ride! You will learn along the way!
Info: 434", Roller cam, Brodix Heads,1050 Dominator, ATI converter, 4.56 Dana 32X14 stiff side wall M/T's

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o1heavy said:
Thinking of replacing the 727 with a cope 904 simply for the E.T gains
But a little concerned about the low first gear
Will it still help with a stroker
I have 456 in the Dana with a 28 inch
Almost feel like I may be using to much reduction when coupled with the low first gear with the 904
Any insight would be appreciated
Thanks guys
Engine
Basic 408
Should make 560-590hp
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Who told you 904's uave 2.77 1st?

904's and 727's have 2.45 low.
904's had an option of 2.77 but it is a 998.

Mopar speed secrets suggest 2.77 but when the books were written 4" stroke smallblocks didn't exist.

2.44 is more than plenty gear.
Actually a 2 spd 1.80 first is more than plenty with strokers if you have low rears.
 
Leon441 said:
Who told you 904's uave 2.77 1st?

904's and 727's have 2.45 low.
904's had an option of 2.77 but it is a 998.

Mopar speed secrets suggest 2.77 but when the books were written 4" stroke smallblocks didn't exist.

2.44 is more than plenty gear.
Actually a 2 spd 1.80 first is more than plenty with strokers if you have low rears.
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I decided not to use a low first gearset
People are making them work but They can be a pain with the 4” stroke
Leaf springs with the short front segment
Along with a Transbrake aren’t real happy together but can be made to work
Just have to buy a shock that will take a brand x car into the mid 5’s to make the mopar run a mid 6
But I’m sure you already know this
But I did not or I would like to think I would have just 4 linked the car
 
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