Tranny/converter questions

[theothergarth]

I have a 74 Duster with a 318 (bored .40 over) with a Comp Cams Xtreme Energy (XE275HL) cam (Duration at 050" lift: 231int/237exh). The transmission is a 904.
The 1st problem: The car is up on jack stands currently. When I have the motor running in park it idles fine. When I put it in drive the wheels spin fine. If I apply the brakes, the motor will stall. It's like braking a manual tranny car without pushing in the clutch. It seems to me the torque converter would be the problem here. Any opinions?


It is not a stock converter, but if I need to replace it, I would like to pick the correct stall speed. I am thinking 2500 or 2600 RPM. This will be a street machine. Any opinions?

 

[oldkimmer]

............is it a lock up trans......if not, its not the converter.......kim...............

 

[theothergarth]

I don't know for sure, but I think it is a lock up

 

[theothergarth]

if it helps....
Compression ratio: 9.5:1
Carburetor or injector size: Edlebrock 750
Rearend gear ratio: I figured it out quite a while ago....I think around a 3.55

 

[tekslk]

I had same problem with cam like yours, none lockup, went from stock to a hughes 2000 converter and it fixed my problem, that was 2 years ago I blew transmission clutches this weekend I think I will go with a hughes 2500.

 

[70aarcuda]

you probably need to tune the engine for the camshaft....

here we go again.........

how much initial timing due you have in the engine?

what carb.?

I had the same cam in a 360....idled great a 750 rpm...with 2200 stall converter...but i had a lot of initial timing in it so it would not drop rpm in gear ..and was using a 750 holley..

 

[tekslk]

I run 19 initial, total of 36, what do you call alot?

 

[70aarcuda]

I run 19 initial, total of 36, what do you call alot?

what carb are you using?...what rpm does it idle at in park or neutral..?

 

[crackedback]

That a BIG camshaft for a 9.5:1 318

750 ede carbs are JUNK! Sorry had to get that out.

If that thing doesn't have at least 24* initial, it's likely not gonna run.

 

[zijmer]

I don't know for sure, but I think it is a lock up

if it's the original '74 904 tranny, it wont be a lockup.

 

[BillGrissom]

What if you give it a little gas as you apply the brakes. Does it still stall? I agree it is more likely an engine idling problem than a transmission problem. You might try loading the engine with the alternator (apply 12 V across field) or AC compressor, and see if it dies then. 750 cfm is a big carb for a 318, especially since not spread-bore, so you will never get a good idle and good mileage. When it is running in N, what does it sound like - smooth or blub-blub? Worst-case, you could take out the 4 converter bolts and see if you can spin it freely by hand, with the ignition on (in case that affects lockup).