I'm planning to build a 302 with about 300 plus horses. Fairly mild build. I'll be running a C4 with a B&M shift kit. I'm wondering if anyone would suggest to run a lock up converter or if you think it's even necessary for a HP motor like this. Any cons using one?
There are no lock-up converters for a C4. I don't recommend B&M kits for the C4s - too many folks have had problems with them - Use a TransGo 40-2 reprogramming kit for your 70 - later C4.
I agree on the transgo kit. I haven't had a problem w/ the B&M but I did notice that the Transgo definately shifted better.
Well, the tranny i picked up already has a B&M shift kit installed... I'll hope for the best. As for the C-4 converter, I was told a 1800-2000 stall should work for my application. Does this sound right? carburetor EDL-1406 (600 CFM 4 barrel) intake EDL-7521 (RPM Performer Intake) heads EDL-60379 (Aluminum Heads) Comp cam XE266HR (.544 lift, 1600-5600 RPM range) gears 3:25 (Stock) Motor is a 1993 HO Roller Cam 302 Car is a 1964 Comet - 2,861 lbs
I dont see why the converter wouldn't work... your not running a huge cam so it shouldn't need a high stall converter either
Cool... I just read another link that talked about stall speeds and suggested no more than 2500 for a street car with low end power. (.500) My Comet weights in at 2,861 lbs... pretty light so I guess the 2000 mark would serve me okay.
As long as you like the way it drives, that's really all that matters. The converter you have may not be a perfect match, but as long as it takes off the way you like it, and doesn't try to push you while you have your foot on the brake, you'll be fine. Goodluck!
Has anyone ever offered an improved C5 lock up TQ? I understand the originals aren't reliable but it sure would be nice to have a lock up TQ for a C4. I'd like to run a higher stall for better launch but chose not to 'cause I didn't want it sloshing around town at 1500 rpm.
The C5 used a centrifugal clutch to lock the converter. There is no way to use any other kind of lock-up device that will work given the fluid flow and dynamics of the converter. If you could make a centrifugal device that would remain completely "OFF" until a certain RPM and then "snap" on to a fully locked position that was capable of taking the 3 - 400 foot pounds of torque that can be produced it would be a workable solution - but no, no one has built the "better mouse trap" for a locking converter for the C4 family of transmissions. It is a shame too because that would provide a 9% increase in the efficiency of the transmission.
You can buy a BETTER Converter$$$$$. My converter was guarnteed to have no more than 3% slippage.( most converters have upward of 6% or more) I havent data loged the converter to drive shaft rpms, But i did notice a rpm drop at cruise speed.
Thanks Andy, the problem with the C5 converters is that the lock-up feature wears quickly because of partial locking. (like any centrifugal clutch)
Thanks, Paul and Andy. Hope I didn't hi jack -- question seemed relevant to the thread. Guess AOD is the only way to go for a lock up TQ. Oh well, maybe in Phase 2 of my build.
