..how many more rpms should the stall converter be from the beginning powerband rpm of the cam?

It all depends on how good the car hooks and the weight of the car. If the car doesn't hook well then too much stall will make it worse.

Well actually I was thinking say for example if the cam is good from 2k-6k rpm then a 2500 stall would be the best to ensure the engine is already in the powerband when the stall finally kicks in.

I would say 1000 to 2000 above the minimum powerband, But I have found the quickest ET's when the Converter flashes to the peak or right within the peak band.

My motors over the last 6 years have had very flat torque curves so hitting this area has not been too difficult.

If you look at most cam companies powerbands they will fib a little.

Take the CompCams 280 Magnum for example.
The chart says it has a power range of 2000-6000.

If you were to stuff a 11inch 2200-2500 stall in it it would be ok and live but you will be sacrificing performance.It will take a bit to get up into the meat of the power curve, it is something you can feel.
At this point darn near any companies converter will be ok.

If you were to install a 10inch 3000-3500 stall in it.. it is going to feel like a totaly different animal, the kind we all like :D
At this point you should consider a good converter from one of the topline companies such as ATI,Coan.It may cost more over a converter from B&M or TCI, but it pays off in less slippage and heat.Less slippage also means quicker ET's and higher MPH at the track with greater streetability graemlins/thumbsup.gif

Now a 10inch 3400-3800 stall is going to really bring this thing alive on the street and at the track it will be slamming you back in the seat with ease when in the lower gears.During daily driving on the street though it might have too much slip for your taste when accelerating in high gear, another need for the good converter.

At this point if you don't get a good converter you are sacrificing much in performance and are probably making many compromises in your total package engine/trans/rear.
This will mean decreased performance with you scartching your head wondering why others with "Basically the same combination" are running much quicker and faster.

I run a good 3000 converter with a cam that comes on at 2000 (226 @ .050 int), the car is a handfull out the hole on regular street tires. I think by the time you get a converter up to this range, the chassis has to be right. I would almost be better off with a 2000 - 2400 converter or moving the power band way up to kill some bottum end. At this point I am going to adress this in the most economical way - probably a cam swap.

Why not work on the chassis and tires :D

I can't imagine a N/A car with a doggy bottom end and midrange will be quicker than something that hooks and comes out of the hole like gangbusters smile.gif

Ok, now what about if you have a 4.10 rear gear like I do...can't you then get away with a little less stall to get her moving?

With this gear ratio:

What stall would be good would be good with an XE284 cam (2300-6500 rpm)?

Joe,IMHO and experience,"economical way" wouldn't involve a cam change..especially with all the cam/lifter "drama" out there.A convertor with less stall would be best,or just deal with what you have..my cam's powerband is 2000-6000,and I have a 2400 Holeshot that flashes to about 2800,perfect for my combo,and no noticeable slippage even with the tall gears.I might step up to a 3000-3400 10" once the 3.31's go in.

Dawg-
You should go with their recommendation on that one, which is by the way a MINIMUM rating.
Using a higher rated converter will only mean better ET's if you can hook it.

Do not get a 11inch converter with that cam.That's going to be too tight.
If a company tells you that their 11inch will work , you don't want it because it will be built to the loose side and most likely will not be very efficient.

Get at least a 10inch that will flash at a rated 2800-3200 WITH A SMALL BLOCK.
Ask the converter company you will be dealing with, not some representative of a mail order catalog.

A big block since it makes more torque will flash the converter harder and create a higher rpm of lock up.This is something to keep in mind when taking converter advice from anyone with a BB.It is not going to be the same.

My TCI 11inch was rated at 2600 but behind my SB350 it only hits 2400 with slicks and 3.42's.
Behind a BB this rpm would have likely been about 400rpm or so higher.

Your vehicle weight,gear ratio,and tire size will also change the rpm but not to nearly the extent the torque of the engine makes.

the convertors from tsi ( big end) seem to be pretty efficient......im crossing the finsh line at 5900-6000 rpms at 104 plus mph and with my gear ratio and tires size im comming up with something like 92% efficiency......theres only about 444 rpms difference......and thats comming from a 12" convertor that stalls at 2800 rpms..........for 150 bucks to my front door off ebay.......new

I'll bring up a noticeable point for you to consider. My car had a 3500 stall TCI converter in it when I got it {w/ 3.31 gears}. This was a very loose converter the way it was made, or at least in the shape I got it. It would start to lock up at 2500 but would slip all the way to 3500. I took the converter into Pat's (Phila. area) and had it gone through and tightened up to 3000. Now it will flash to 2500 and tighten up real hard at 2900 - 3000. Using a loose 11" converter to get the stall you want vs a tight 10" makes a big difference.

i agree with thrasher, the cam companies fib ALOT. a bone stock 350 from the early 70's or late 60's didn't make it's peak torque until around 3500-3800rpms. you want your convertor to flash right at the point where your motor makes peak torque, or within 500 rpms or so. if you run an XE284 cam in a 355 i would say your powerband is going to be peaky, not very flat. as far as gears go, i would 100 times rather have a properly matched convertor than the optimum gear, within reason of course. to get the most out of that 355 and an XE284 cam i would think at least a 3500rpm stall, probably more like 4000rpm stall to really get every last ounce of ET out of it. but a 4000 stall would be a PITA on the street, IMO. my opinion is go with an XE274 and a 3000-3200rpm convertor. graemlins/thumbsup.gif

Thanx. After much reading sounds like this would be the best combo for my 350 build up.