Hi All, I'm wanting to update my stock converter and I was wondering what brands are recommended for 455's. My car is a '71 lark stock 455 with 3.08 gears and I'm looking for something around 2000 stall. Thanks in advance, Kirk
Why? Stock 455? What do you think you are going to gain with a different converter? With a stock cam, you have the best converter now.
I was just wandering what converter brands are recommended, besides B & M and TCI. My engine is getting a cam swap and ignition upgrade. I have a Daves smallbody hei and I know what stall speed I need. Thanks Kirk
Buy the best converter you can afford. You get what you pay for with converters. Coan is one of the best.
do cheap convertors rattle????? on my buddy's lark he bought a cheap convertor and it makes a rattle on motor mashing.. atleast i think its the cheapo convertor not sure... but anyways my recent tranny experience proved Larry to be in the know. he knows his bidness about buickss.. BTW i stumbled upon larry racing a 69 400 gs on google video.. damn his car is fast .. both of them... what the hell does that red gs have done to it...?? not tryin to steal the thread just in awe over that vid. http://video.google.com/videoplay?docid=-6984591945218519863&q=buick+gs+400 i dont live too far from cecil co. next time you guys are in town lemme know ... i owe larry a beer or 10 for his wisdom.. :beer :beer :beer :beer
ATI - Very good... I use an ATI Convertor. I really like it. It's a 2800 stall, 455 engine 475 hp give or take, and TH350 trans. Good stuff. http://www.atiperformanceproducts.com/products/tc/tc.htm Later; Mike
Higher stall WILL help! Hi Kirk, Gary here. When I had a bone stock 430 in my 67 GS, I had a 2000-3000 stall switch pitch converter(from a TH300 trans). Let me tell you, when it was in 3000 stall mode, the differance was dramatic. The previously mentioned 2800 ATI will not only be faster than my switch pitch, due to 30 years of improvements, it will be tough as nails also. The ATI and COAN converters are rather tight on the high end and help your ET and MPH all the way down the track. Cheap converters will feel looser and run hotter when highway driving, even if the break stall (2800 or whatever) is the same. There is some real tricky enginering inside a converter and cheap ones fall short most the time. A good choice NOW will be there for you in the future as you make other power improvements to pick up your performance. Yes, a good 2800 converter will improve your stock car, (just like the antique switch pitch did for the old 65-67 stock GS's), only better. Do a search for EDGE converters. Some Buick guys told me you get a guarantee and best features for a little less cost. But check around. Pick the best price amoung the best converters.
Thanks Gary. I have tried cheap converters in the past and they felt loose, just as you said. It seamed as if the vehicle stopped pulling once I shifted into high gear. Oh, by the way, did you get in touch with John Carden concerning your water pump situation?? Thanks Kirk
stall I think a key unasked question here is - what kind of driving do you mostly do??? If you do alot of 55-60 mph on country roads with 3.08's you are only turning like 2200 rpm depending on tire dia. I think even a high quality 2800 stall non-lockup convertor may be slipping too much that far below it's coupling range and cause cause heat issues. Don't count out the benefits of a good aftermarket switch pitch convertor. The idea may be antique, but it was engineered for a reason. That is to give you the added performance on launch like you are looking for while giving good manners in tight mode. My .02 for what it's worth. Todd
SP converter Hi kirk, I did talk to John, for about an hour in fact. TODD IS RIGHT. If you have a turbo 400, a conversion kit and switch pitch may be a good idea. It is the best of both worlds if you want street and strip. The high stall side is impressive at the track and the low side is as good as any stock type converter. The only reason to use a high dollar converter is to squeek out another tenth or two at the track and not have a lot of slip cruising, but they DO NOT tighten up like a switch pitch for cruising. The 2000-3000 version would put a smile on your face for sure. The cost of the kit and converter may be less than an ATI converter.
S/P convertion Thanks Todd, You know, I do have a th400 lying in the shop corner. Its from a '73 225, but it has a long tail shaft. I think I will check on the S/P conversion kit. Gary, do you know of any suppliers for the kit? Thanks, Kirk
s/p conversion I found some switch pitch tranny's and one kit on PARTS FOR SALE near the bottom of this site. Go to the top right of the blue bar and put "switch pitch" in the search box. Most are in the 300-350 price range. From salvage yards, you want 65-67 Buick, Olds, Cadillac TH400 transmitions, but the best converters are from TH300 2-speed tranny's. Best to get a built converter from PAE or Trishield. The conversion parts can be taken from any old S/P 400 trans and installed in later model cases. The 300 converters have better stall speeds and are smaller than the big 400 s/p converters. I've seen junk/salvage converters run at the track and last for years. Nailhead tranny's do not fit 400-455 blocks, but the conversion parts work in any 400 trans. Do not accept conversion parts from TH300 tranny's, they don't fit a 400.
Kit 40 year old parts cars are getting real scarce around my neck of the woods, so if you cant find a sp-400 in the boneyard try this http://www.paeenterprises.com/paeframe.html Go to product index, then switch pitch convertors. The conversion kit is at the bottom of the page. Go with a convertor in the 3,000 low stall range. Don't get tempted by the 4,000 & 5,000 stall units. On a stock or mostly stock motor it would be all out of breath before you were really moving. Do a search and read about some of the other members experiences with thier S-P's and of the different units available on the market. Wasn't all that long ago I was asking similar questions to yours. There is alot of valueable reading in old posts. Todd
PAE site Kirk, I pulled up the PAE site. After some experimenting, I finally clicked the right keys and found the s/p conversion kit for $295. The converter was the same price, but low stall was 1100 rpm and high was 3000. I would prefer the orig unmodified 2000-3000 so the trans would not pull on the car at a stopsign. I get a little pull even with 2000, but 1100 would be a nusance. You could probably request an unmodified version if you choose to buy from a vendor.
A unmodified SP-400 convertor won't go anywhere near 3,000 stall, more like low 2k's. A stock sp-300 convertor will stall more like that and maybe fit the bill for you if you can find one. Maybe that's what you have Gary. IMHO you are best off just to order one of the aftermarket convertors. Slapping on a used one with a mysterious past could take out a new tranny and cost you more than a new convertor would have. Also you want the low stall during cruising conditions to be nice and tight, that keeps heat down and drastically extends transmission life. Switch your convertor so you are in high stall at lights if creeping or idle quality is an issue. That's the whole point of a Switch Pitch, not just launching. Todd
Hi Gary and Todd, I was wondering about the benefits of the s/p 400 at the track. Other than the launch, is it useful down the track when it is switched to low stall ???? Thanks again, Kirk
