I had Neil Chance spec a converter for my car which ends up being about a 4500 stall and it actually stand to be a little looser. Anyways could a converter like cause a weak bottom end? doesnt seem like it has much low end grunt at all. engine is a 355 Buick, 10.5:1 compression balanced and blueprinted, pretty much stock heads except for a slight mill and larger valves, 230/237 .525/.531 110lsa hydraulic roller cam, 1 3/4 headers, 1.6 roller rockers, sp3 intake, Holley hp750 built by Seibert performance.
Sure, a converter that isn't built tight is not very efficient in real world street driving. It makes the car feel lazy on the street, but it goes like hell when you jump on it. Unless the car is a race car, efficiency matters. What you want is a converter you don't know is there until you punch it. I just swapped in one of Jim Weise's 9.5" converters, and that is exactly what I got. http://www.v8buick.com/index.php?threads/tsp-9-5-street-strip-converters-lifetime-warrantee.147066/ I don't think I have ever seen a bad review of one of these converters. Read the thread. Also not sure why you need a 4500 stall in a street driven car with a mild engine. 3500 or even 2500, would be more than enough.
X2 on what Larry said. I too have one of Jim's 9.5" converters and he built it for my big 69 Riv. It really turned that car on and woke it up.
My car also has a 9.5 3500 stall Jim converter,but I have a 455 with it.With a 4.500 you should be shifting past 6000,the 350 will do that?Bruno.
I like ATI 8in BUT the tightest one they make ....4200 stall. Quite a bit lighter still than the 9.5. Works well street or strip....
I have A JW 9.5" convertor, just sent it out for a re-stall, added another 500 rpm, I twice shifted to second at 7000 rpm, pulled great
I also have an ATI. But only cause i was not tied in with the guys here. On the forum. Very nervous about where i bought a converter . looking back now. They know best.
Same here, I had a B&M and a TCI in my GS, till I read on here about JW's custom built convertors. Im sure "shelf" convertors are fine, but when your going to spend 6 to 800 bucks I'd prefer to have one made for my combo. It was money well spent
Having had a bad experience with an “off the shelf” converter… I recommend using a product that the guys here have history with. The shelf converter ballooned and caused all kinds of problems for me.