ok guys here is my future set up in my 70 mav, and im 100% sure on everything except the torque converter. stall or no stall? i kinda can understand it, but then i get lost as im not sure the difference in real life. so my future set up will be a 347 (400hp/425t) with a street fighter c4 trans. the rear gears will probably be 3.55 i suppose or close as i will also have the gear vendors overdrive tail piece with it and that company will help me figure the rear with my wheel height considered. so with that said if i get a no stall converter, what will it run like at idle and then normal street take off and sometimes hard running on the road? VS a stall converter? ive read a 2000-2500 stall is recommended. what will this do at idle and take off? im not going to race it, itll be street only but i want it to be able to burn the tires sometimes if i feel like it. so with that said all i can compare is my old 302 (220hp?) with a c4 auto vs my 06 jeep liberty auto trans with what i assume has a stall converter. the old 302 is instant forward motion and a hard peddle feel vs my liberty and other newer cars that has a mushy peddle feel and revs higher than idle before it really starts moving (split seconds). so how does it feel one vs the other? and how will a 400hp engine behave with a no stall vs a stall? thanks sorry im so confused.
There are a lot of factors involved with the main one being the cam shaft. You need to match the convertor to the cam, if it has a nasty, lopey idle you will need some stall speed. If you can post up more details of your future engine build you will get some better answers. As far as pedal feel, most new cars use fly by wire so the pedals are dead and mushy feeling, I can't stand that! Most newer cars do feel like they have a loose convertor, I think they can get away with it because of the lock up feature.
With 400 hp in a car this light weight, you would be able to roast the tires anytime you want, even with a stock 2.79 gear set. If you are not going to the track often, my thought is a decent converter around a stock stall speed will be the best feel for everyday driving.
Anything with a lopy cam needs some increase in stall speed, makes no difference if it has 400 Hp at 6k RPMs, it'll be a dog pulling away from the curb... If you are using a O/D go for approx 2400 RPM... I have a 2200 Hughes in my mildly cammed Comet, makes for nice all round performance...
ill be using this exact 347.. http://www.jegs.com/i/Blueprint-Engines/138/BP3474CTC/10002/-1 so does the stall act like a clutch on a manual? with a lopey cam in a manual i always had to give it a little more rev while letting the clutch out, while on a stock cam it was alway eaiser to get going without it dying. just thought of this after reading yalls replies.
A stall convertor acts just like any automatic except it will slip more off idle depending on the rating. The rating is also just a ball park, each combination will work differently depending on a lot of factors. I had a TCI 3500 in my GTO with a 455, when you hammered it the tach would hit 4000. The same convertor (literally, I gave it to him) in my brothers Chevelle with a high revving 350 could only muster 3200. With the combination you are looking at I would take Krazy Comets advice and go 2400, with a light car it will act like a little less of a convertor but should be just right and driveable.
Are you running C4 and what axle ratio.? I have headers, 600 cfm, mild cam and C4 w/ 2.79 ratio. I am going to have work done on my trans to basically stop the leaking -- shifts fine, has shift kit. I have stock converter, only use the car for cruising. My question -- thinking about converter change along w/ trans work. I am leaning toward going again w/ stock or something vry close. Looking for thoughts/opinions B4 committing. I like what I have now and don't want much in the way of change in driveability.
C4, 3:00 gear(but the 255s makes it closer to 2.79), small Lunati Voodoo cam, approx equal to a HO 5.0... If I swap to a AOD it'd have the 2600 stall that I used in that trans... I'd probably switch to 3.70 or 3.80 gears if it had O/D, love the 3.73 in my Bird... With AOD in 4th gear(O/D)the final ratio using 3.73 is 2.50, great cruising gear...
It literally won't idle in gear without some sort of stall. 2000-2500 will actually make it much more drivable.
thanks for the info guys. it all makes sense now. without running the rpms up a little with a lopey cam it would die or be very sluggish. now i understand.
