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I'm bringing mine with the 6=8 clifford twin webber higher than that. seems pretty good up 5000
 
I know tuned and balanced slants can go up to 6,000 without a problem. I have my module limiter set for 5,800 but I'm sure I could go higher if I really wanted to. Almost nothing about the inside or outside of my motor is stock though.
 
Not sure on HP yet. Still lots of tuning to do.

Bored .60 over, crank and rods balanced, 280/270 Erson cam, Eddy 600CFM carbon an Offy Intake with dual Dutra Duals, cylinder head ported, polished and planed .100" with larger valves and hardened seats, HEI ignition with a Flamethrower module and a recurved distributor, 2600 stall converter on the 904. It's definitely quicker, but I still think I'm leaving a lot of HP on the table. I wanted to use a 500 cfm carb, but the one I have seems to be FUBAR, so I bummed the 600 off a friend and it runs much much better. Not sure how it would do with a good smaller carb, but we'll find out someday. Maybe I'll find a good deal on one at Carlisle.

Ideally, I'd like to get 200 HP at the wheels but that might be a pipe dream without forced induction.
 
wow nive, i m .60 over , shaved .100 off the head, i ported the head myself ( not flow tested ) and open her up a bit in back of the valve and removed casting flash, and polished it up bit. i have the clifford dual webber carb set up. i m still playing with the distributor to get the timing where it is best.my crank is 1967 so i couldn't fit the newer high stall torque converter, i found a later forged crank anyway , but the machine shop says that they can machine the crank end to fit the newer tranny.. i have the 268 cam in her now . i m happy with the performance
i think I'm going to retard the cam to get more at the bottom end and less at the top . i have 294 gears in the diff with a mopar sure grip. it won't spin the wheels , so I'm in the middle of what to do
do i try to put more power at the bottom or wait till i get the highstall torque in it, do i drop the gears to 355
or back off my cam 3 degrease . ???
 
You guys need to state your engine size. The 225 has a 4.12 stroke and the 170 is exactly 1" shorter and higher revving. I think the NASCAR hypers turned 7000.
I doubt my 225 will ever see 4500. (unless my son borrows it without me riding shotgun] Didn't build it for that. I have a small Autometer tach around but it hasn't turned up yet.
 
A few years back, I was bracket racing a Duster with a 225. Bone stock bottom end and the only mods were an Offy intake, Holley 4412 2 barrel and Mopar 6x1 header. I turned it 5500 pretty regularly but it quit making power much sooner. Basically just to see what it could take. That particular engine wouldn't die.

I did have a 225 cast crank engine in a 1980 Diplomat that slung a rod out of the side of the block and kept running. Only slant six engine I've ever had to let me down.
 
I used to rev mine to 4500 all the time. That way, when the A904 shifted, it would continue to pull.Otherwise the rpm was so low going into second, she would drag her azz a long ways before picking up again. 4800/5000 was better,yet.
Leave the cam alone for now.
Wait for the hi-stall. It will make the biggest difference off the line.Especially with that cam.
2.94s suck!, even 3.55s are not enough to really wake up a slanty.That cam demands Performance gears. But really the 904 has a 1-2 split of 59%, meaning that whatever you rev it too, the rpm will drop to 59%. So if you rev it to 4500, the Rs will drop to 2650ish,plus slip, and that is a deep dark hole for a 268* cam to pull out of. Ima thinking that slanty is gonna want a 3000TC or better. And if that is close, then hi-way cruising is not gonna be a lotta fun, so you might as well give it up and go straight to 3.91s! Between those two, your slanty is finally gonna wake up.Top of second will be about 60/65 mph, depending on tire size and where you decide to rev her to.
Cruising the hi-way 60 might be about 3000 to 3200
By the way,with your current combo,moving the cam 3* is almost pointless .For me it would not be worth the time.
 
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+1 with what A/J has said.

You need a fairly deep set of gears and a fairly high stall converter to get the slant moving out of the hole. It's best to get a converter from a company like Edge or PTC to where you can specify to them that the converter will be for a 6 cylinder engine. Buying an off shelf converter for a 904 v8 application will leave you disappointed because you won't get anywhere near it's rated stall with a 6. I know that Edge will build it specifically to your combination.
 
there are local torque shops in montreal , i wonder if they can do it , i rather sacrifice take off for rpm at 70 mph
i don't want it reving at 3500 + at 70 i have 225 70 14 tires on her now
 
i appreciate your knowledge.i'm going to pull the engine and swap the crank so i can get on the 82 transmission
and install the high stall torque and with the lock up .and see how she performs
 
that 268* will want to spin!
In a 360 it will make peak power at maybe 5000/5200, and with an automatic, will want to be shifted at 6200 to drop into second at 3660.
In your slanty, IDK, but it will probably be higher. That's a lotta Rs for the long-stroke 225.Was your engine built to endure those rpms?
But say you shift it at 5000. With 2.94s,26.4 tires, and 5% TC slip, this will be about 47mph, with a 2.74 low gear. Then the slanty will have to pull from 2800, or your new stall speed,and will hit 65@ at about 3886, with over a 1300 rpm to go, to reach the power peak, and several hundred more to the optimum shift-rpm. For me, this would be the slow way. I want my engine to reach the optimum shift rpm at 60/65. This will put the most average power down during the run. For you, this would require 3.91s, to hit 65@5200, or (5% slip);still low for that cam. Maybe not so good for your engine tho.... And you would outshift first at about 33.5mph,instead of 45mph. oh yeah!
But this is not where the cam wants to be shifted.
So really you might be at least one cam size too big, and perhaps as many as 3;unless your engine was built to live up at those rpms.
And the 67Bel could sure use the extra footpounds on the bottom, that a smaller cam would bring.
But then again, the cruise revs at 65 would be perhaps 3235 in loc-up. And you were not interested in that........

So if the 2.94s have to stay............. Your cam is waaay too big for the stock TC. To get off the line optimally, I imagine that cam will want about a 3600/4000TC, and downgraded to street, maybe 3000. And with the cruise rpm currently at about 65=2400, you can see the dilemma. Your combo needs another tranny gear, and 3.91s.
BTW, I'm not hating on your 225. I'm just pointing out, that for your useage, the combo is not optimal, and a higher stall may not get you the results you're after. I hope I'm wrong.
 
not at all i see what you say and totally understand.i'm trying to get just a bit more off the line. for now
i driving her the way she is , summer is short as you know, so just getting some ideas going.
i wish i would of known when i put the engine in ,that 67 crank won't fit the newer tranny as the transmission guy
said it would , the engine machine shop knew right away when asked if they had another crank.
they told me they machine the early ones to fit, but i got a later (1975) anyway so when i pulled the engine I'm not looking for a crank.
 
"But say you shift it at 5000. With 2.94s,26.4 tires, and 5% TC slip, this will be about 47mph"
when i hold it in 2nd gear I'm doing 75 mph about @ 5000 not 47
 
67belevdere/225 said:
"But say you shift it at 5000. With 2.94s,26.4 tires, and 5% TC slip, this will be about 47mph"
when i hold it in 2nd gear I'm doing 75 mph about @ 5000 not 47
Click to expand...

But say you shift it at 5000. With 2.94s,26.4 tires, and 5% TC slip, this will be about 47mph, with a 2.74 low gear. Then the slanty will have to pull from 2800, or your new stall speed,and will hit 65@ at about 3886, with over a 1300 rpm to go, to reach the power peak, and several hundred more to the optimum shift-rpm.

To get 75 in second with the current A904(1.45 second),and 2.94s, and 26.4s, the rpm should be 4071 plus TC-slip. If you are doing it at 5000 then your TC is slipping; 5000/4071=22.8% and so it is junk.
However, it is more likely that the speed-O is in error. The math at a more sane 5% slip, would put the mph at a true 88.
Of course, I suppose the 2.94s are not really 2.94s,heehee. If 75indicated=75true mph and the TC slip is 5%, then the rear gear might be 3.73s
Of course the tach could by lieing too,I suppose. If 75=75 and 2.94=2.94 then the tach should be reading 4072 plus slip. At 5% slip, this would be 4276rpm.

Here is the formula, have fun;
mph= (rpm X tc)/(1056 X rear gear X tranny gear)
where tc is the Tire Circumference, which is the tire diameter X Pi(3.1416), which is also called the tire roll-out.

If you want to know where to shift, get yourself a G-TecPro windshield-mounted accelerometer. Follow the instructions. It will record your "power" during the run, and generate a curve. The top of the curve will be where your horsepower peaks. This is not the redline, and not the shift rpm.It is just the rpm of the power-peak. And the peak may be several hundred rpm wide.
The redline is the rpm where your piston-speed becomes excessively high, and and the piston is in danger of blowing up, or tearing off the rod.
The shift rpm will be the rpm where the outgoing horsepower is equal to the incoming horsepower. With a 904, this can occur over 1000 rpm after the power peak. Your job is too make sure the shift-rpm occurs well before the redline.
At the racetrack, you do not want to carry the final gear all the way to the shift rpm thru the traps. That's just needless wear and tear on the engine. Rather, you want to trap at an rpm where the power is just nosing over the top of the curve.
For a streeter,the same can be said of at what rpm to hit 60 mph.

And I know you probably couldn't give a hoot about either of those things,today..........but one day the bug might bite.......
Have fun!
 
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67belevdere/225 said:
i think I'm going to retard the cam to get more at the bottom end and less at the top .
Click to expand...
I am not sure this has been noticed but the above statement is backwards..... You should advance the cam timing to get more low RPM torque. I disagree on moving the cam 3 degrees... it will make a noticeable difference but not a huge one with just 3 degrees change. I don't know this cam's ground-in advance, if any, but going to an ICL of 106 or even 104 is the kind of recommendations I have read (and which make sense with any moderate compression ratio engine if you want better low RPM torque).

I also don't think the HP peak will be at 5000 RPM with this head and cam; there is 56 degrees difference in the advertised duration and the .050" lift duration... it is not a big cam. So that changes the numbers on RPM's at shift points and TC stall.
 
I saw that but, I just glossed over it

But since you're here,nm9, are you saying his 268* cam is a 212@050? Well the guy who suggested that cam for this combo should ............... be spanked lol.

If it was mine, I'd heave that monster post haste. I know nothing about slanty cams, but when it comes to FTH for SBMs you can get a 212@050 with as little as maybe 252 advertised, and that would bring the Dcr way up, and so strengthen the bottom end a lot, without affecting the top whatsoever.
I think I have a 252ish in my slanty, also with hiway gears and with 9.5 Scr. At least that is what I asked the builder to supply me with in 1994. And no,my-bad, I never checked it. The bottom-end is not weak with a SS intake, but the old Volare combo is just all-around weak,lol.
 
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Of course the tach could by lieing too,I suppose. If 75=75 and 2.94=2.94 then the tach should be reading 4072 plus slip. At 5% slip, this would be 4276rpm.
i'm going out after and will look at rpm and speedo , i just read quick your response , thanks for all the dedication to my quest
really i do
thanks again
 
Let's say that 225 has a Scr of 9.2.
With the 268*/110 in at 106, and an ICA of 60*, the Dcr comes in at about 7.6/150psi.
But with a 252*/110 also in at 106, and an ICA of 52*, the Dcr might come in at about 8.0/160
That extra compression would really be felt out of the gate. The loss of 16* of intake duration is just over 2 cam sizes, and so the power peak might come down about 400 rpm. This would be a good thing I think (not knowing much about 225s except they have a 4.125 stroke and 7 inch rods), and the power would also be a fair bit less, but nothing that 3.23s can't cover.
And perhaps the hi-stall would not be needed. But if you did still install say a 2800, and with the 2.74 low gear,(8.85 starter gear vs 7.20 currently) this would jump pretty good.This would be a 23% improvement in starter gear, and with a 2800 vs the 1750 stocker, there might be I'm guessing, an extra 20 ft lbs there, so that could add up to an improvement between plus 40% to plus 50%. That is a huge deal! Kindof like bolting a supercharger onto the current combo.
But to be fair, when you hit the upper midrange in second gear, you will notice the power difference, but with 3.23s this will occur after 65mph, so.......no big deal to me. 65 will be about 4300 with a 1.54 second gear and the 3.23s.

But it all goes back to the current exact compression ratio. I picked 9.2 to illustrate that the 252* cam is getting up there in Dcr(8.0). With a poor chamber design, that's possibly pushing the limit of 87 gas.
And 3.23s would cruise at about 65=2674 in loc-up.
I could be happy with that.......
 
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nm9stheham said:
I am not sure this has been noticed but the above statement is backwards..... You should advance the cam timing to get more low RPM torque. I disagree on moving the cam 3 degrees... it will make a noticeable difference but not a huge one with just 3 degrees change. I don't know this cam's ground-in advance, if any, but going to an ICL of 106 or even 104 is the kind of recommendations I have read (and which make sense with any moderate compression ratio engine if you want better low RPM torque).

I also don't think the HP peak will be at 5000 RPM with this head and cam; there is 56 degrees difference in the advertised duration and the .050" lift duration... it is not a big cam. So that changes the numbers on RPM's at shift points and TC stall.
Click to expand...
yes, i meant it was too advanced !
 
67belevdere/225 said:
Of course the tach could by lieing too,I suppose. If 75=75 and 2.94=2.94 then the tach should be reading 4072 plus slip. At 5% slip, this would be 4276rpm.
Click to expand...
I get about the same numbers as above for 2nd gear at 75 mph. (I used 25.5" tire diameter to account for the radial flat shape on the ground.) If you're actually near to 5000 RPM at 75 mph in 2nd gear, then it may be that you have a 3.31 rear gear....??
 
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