Hey Guys, I finished my putting my 350 back together and I have a few questions for you gurus. I installed a Competion Cam (260H) and a T/A Performance Stage 1 intake. Now I am still testing and expirementing, but my find is that out of the hole, I take off with what seems to be stock acceleration until I hit 30 MPH, and then a huge boost kick in that you can hear and feel. I thought the cause may be the secondary air pot (the shop manual's term for that cover on the top of the carb for the secondaries) was not opening soon enough. I disconnected the assembly but it made severe hesatation when dropping the pedal and did not resolve my attempt for low-end boost. According to the book, there is no adjustment for the vacuum that controls this module. I was considering going with an after market carb, wondering if the stock setup isn't quite the best candidate for these upgrades. I clocked 0-60 at just under 8 seconds and I would like to get it closer to 7 if possible. I feel that if I could get the low end boost that is exuded from the top end, I could acheive the power I know is lurking somethere under the hood. I also considered the parts I installed may perform this way by nature, but I'm not experienced with GM performance let alone Buick so I am consulting the experts :Smarty: (that's you guys.) I will probably eventually install headers in the far futue along with an Edelbrock carb anyway but I wanted some input on this situation to put my mind at ease and save some time; I would feel silly tinkering with something that could never produce the desired results. I am still tinkering with a/f mixture, timing, etc, so I can't rule out anything else at the moment. Oh, and sometimes if I goose the pedal, it kills or stalls a bit. Steady cruising feels like I'm in a new car. Thanks for your time and knowledge,
I'd bet it is the carb. Have you checked the accelerator pump? If you didn't rebuild/retune the carb for the fresh motor that would be the first thing I would either check or replace. I don't have any specifc help for you, I'll leave that for the experts.:TU:
mine did about the same. I have a holley carb, I changed the secondary srping, and it fixed it. I'd just slap a holley 750 on there. and play with secondary springs.
Does the 750 mean CFM? If so, I thought 650 would have been plenty enough. Thanks for the tips so far, guys!:Comp:
You didn't say what RPM range you are launching at. If you haven't yet, I would invest in a 2400-2800 converter to get the rpm's up a little on the launch. Mine with the TA212-Stage1 intake doesn't start to come to life before 2400 rpm. Also check your timing..... a dial back timing light is great for that! Mike
The transmission is bone stock. I haven't really messed with converters any. Would that still give me a streetable feel without excessive stress on the rest of the drivetrain? I'll seriously consider that converter if the situation is right. I had a feeling the parts might not have had the low end I was hoping for. Any other accessories might get that bottom range out a little more? I feel this weird need for speed!!!:Brow:
The converter will definitely give you a harder launch and will not stress out your drive train. The only thing I would make sure you have (I would have anyways) is an external trans cooler. The trans temps will be just a little hotter with the stall converter. The converter will make a world of difference. Mike
What carb do you have? I don't know what an "air pot" is (They used to sell coffee carafes as "air pots" but I don't think that's what you mean!) The Q-Jet has an air valve on top, it absolutely is adjustable. The 4G style Rochester also has an air valve, and it's adjustable too. Been a long time since I was in a Carter, I'm thinking they have air valves (Like the AVS-Air Valve Secondary) I don't remember about adjustabliity.
I'm using the stock Rochester. According to the shop manual, there is no adjustment for this peice, but I'm not sure if is the source of my trouble. There is a slight hesitation when launching sometimes, but I experienced this before I started playing with the motor; it's just not as bad now. I really believe the carb is the problem here. I finally broke and invested in a dwell meter and I now have everything running pretty darn smooth. I am still lacking in the low end, though. There is also the occasional miss during full acceleration. o No: Don't know about that one yet. Im am still in the experemental stage here. Thanks for all the information, guys.:TU: I'm still learning the world of GM one bolt at a time.
bt chance did you degree the cam? i have a comp cam and have felt it to be not too great a performer...i've heard they usually need to be advance a lot in our engines to make decent power.
