alum edelbrock heads

Well then,I have an idea for you.I havent researched it in the a/t arena, but; If you find an O/D tranny that would allow you to use its O/D as a splitter, and chose a set of tranny ratios that worked with the splitting, then you could effectively build a 6 speed trans with very tight ratio splits, and very small rpm-drops during shifts. This would allow you to go to a tighter LDA, and a smaller camshaft,and a lower stall TC,and/or rear-gears to arrive at the same average hp delivery per unit of distance travelled.And this would translate to less fuel useage at part throttle cruising.
What this all boils down to, Im sure you have already figured out. But for those that might not have grasped this; the same mph at the big end, for a smaller cam, or even a smaller engine, than with a conventional 3 spd auto, and/or a more economical-to-operate engine.Translation; more streetable, but still ear-to-ear-grin fast.
Now, the Mopar o/d trannys are out. The .69 o/d ratio is much to deep for effective splitting. A .78 or so would be much closer to what would be needed. So lets back engineer that.
Six speeds is too many for the Qt. With a small street-type engine 5 would be sufficient. A fun Streeter would be a small-cam 360. That engine would do well with a 4 gear Qt, and a 3 gear 1/8th. So lets start with 4 for the 1/4.
Lets say that small cam 360 has the potential to go 106, and the hp peaks about 5400.But that engine has a well chosen support works so the hp falls very slowly after 5600, and is still doing very well at 6000.
So we are gonna want to cross the line around 6000.Lets also chose a 27 inch tire. Doing the math, this gives us a on-the-line ratio of 4.56(convenient,I know). But this will be in 2nd-o/d. so the rear-end ratio x the 2nd gear ratio, will be 4.56/.78= 5.846.
So the tranny ratio times the rear ratio will be 5.846.So we need to find a combination that satisfies this while still giving us a nice final drive.
Well it just so happens that, 5.846/1.45(typical Mopar 2nd) yields a 4.03 gear, which we will round down to 3.91. And also conveniently,3.91 x .78=3.128cruising gear. So we are in good shape so far, with 3.91s out back and a 1.45 second gear. Lets do 1st.
To get to 1st, we first need to get to 1st-o/d,so 1.45/.78=1st-o/d =1.86; and 1st is 1.86/.78 =2.38,None too-far from 2.45, the standard Mopar 1st gear.
--So it looks like the standard Mopar ratios would work pretty good with the .78 gear-splitting, and 3.91s. Lets work it out; the ratios are 2.45-1.91-1.45-1.13-1.00-.78, and the spits are;.78-.76-.78-.88-.78. (Well look at that! if you wanna go really fast, you could gear it(4.56s)to go 5 gears in the qt, and take advantage of that last .88split.)
With this set-up, the starter gear is 3.91x 2.45=9.58. But the TC will multiply that some, perhaps 5%, so lets say 10.06. This is an excellent street starter gear. And if you swap in some 4.56s for the track;the starter gear works out to about 11.7.
And the final-drive of 3.91x.78=3.05, puts you at [email protected] too bad.
--To be sure, there are other transmissions with wider ratios that might work out better with a different splitting ratio.I just chose all the parameters to work with stuff that we are all familiar with.
BTW, the .78 splitting ratio puts the rpm drop from 6000 to 4680, thats a powerband of 1320rpm, centered at 5340rpm.Thats a nice street cam. A 223*@050,fast-rate, high-lift might get you there, with a tight ringseal and good flowing heads.
Personally, Id be looking at the 700R4 and its family.
Okay then, lunch time.

mopar
sorry to hijack your thread.