hey guys,i have some questions.i had a problem back in april regarding my 69 tempest performance after an engine rebuild ,suggestions of gear ratio and headers were given.well i put a new posi unit and 390 gears under her and she's a rocket.the problem now is she's geared too low.what would be the most reliable transmission to go with.the engine is a 69 pontiac 350 making around 350 hp.what auto trans whith od.would bolt up. should i go 4sp. manual trans. or will a later model 5sp.manual bolt up to a pontiac trans.i still didn't get the headers yet,because i don't know wich to get.i have casting 62# heads,what size primary,shorty or long tube thanks for any help or advice you can give me  

Assuming you are using a Th350 trans now, the 200-4r overdrive is a virtual bolt-in, using the same length driveshaft and yoke and same overall dimensions. HPP ran an article years ago on this swap, I can send you the article if you want. The 700r4 is way more involved, it's longer and has a Chevy only bell housing requiring an adapter. A 4-spd manual won't lower your cruise rpm by much, both the th350 and th400 are 1:1 top gear, the same as a 4spd manual, the only difference will be the torque converter slippage. A late model 5 speed is pretty weak and wasn't even available behind a chevy 350, let alone a long stroke Pontiac 350. The best 5spd conversion is one of the aftermarket kits available from the suppliers who advertise in HPP.
As for headers, if you must have them, buy good ones, they won't be cheap but they won't leak like the cheap ones. About 1 5/8" primary and 3" collectors should work for your 350. Shorty or full length, take your pick for best clearance. For the street, power will be about the same for both types. Glad to hear your 350 works so well.
Steve  

thanks steve.do you need my e- mail or can you put the article on my thead?  

Send me a private message with your email address so you don't have to post it for everyone.
Steve  

Sorry to go off topic with my first statement but how were you able to hit 350 horsepower with a poncho 350? That's my goal to make more power than cubic inches. I too have the 350 (70 block) along with the #62 heads with bolt ons and hi-po cam. I understand if you don't want to share your setup lol. I went with Jegs long tube headers (cheap but that's all my budget would allow me to do) but motor is going in soon, heard with cheap headers, modification is needed for clearance (I have a 2nd gen bird which makes it all worse lol). I would also recommend getting a mini high torque starter if you went with long tubes for clearance purposes so you dont have to take the headers off every time changing a starter. Haven't heard anything with shorty's but that it gives you a little more advantage launching from a dead stop than long tubes  

well dave.i didnt say i was making 350hp,i said around 350hp.in reality its more like 340hp,and that wont be until i put headers on.i really dont think 350hp is hard to reach with your 350 and those heads. the cam your using im not sure about.in 1969 they made a 330hp 350cu.10.5:1 comp small valve and a 265hp 2bbl 9.2:1 comp. single exhaust,which is what i started out whith.i then had the block bored 30 over, the #62 heads machined and ported,they have large valves. the cam i used was comp. cams p8 xe268h-10 gross valve lift is.477 int. .480 exh. duration@.50 is224 int. 230 exh the intake manifold is an aluminum pontiac performer dual plane with a 600cfm holley and an hei distributor and accel coil.i hope i helped. i dont pretend to know anything .i ask questions and go with the best  advice.hpp did an article a couple months ago on a 350 build up and made 342hp on the dyno.talk to you again {freach}