seem to have no power
81firebird
05-26-2005, 04:23 PM
Hi guys, i have an 81 firebird with a chevy 267 in it. I recently rebuilt the engine and put in a new cam, the cam is a stock cam from a 350. Thats the cam that my local engine builder recommended. The car idles great and drives around fine but when i give it a punch of gas it will not even try to spin the tires it just kindof bogs down a little then takes off. I know it wont do anything special being a 267 and all but i know it can do more than this. Ive tried lots of things but i cant figure this one out, the only other thing i can think of is that it might be the torque convertor i put in. It was a used one i had layin around.
volkerc
05-26-2005, 05:11 PM
Hi guys, i have an 81 firebird with a chevy 267 in it. I recently rebuilt the engine and put in a new cam, the cam is a stock cam from a 350. Thats the cam that my local engine builder recommended. The car idles great and drives around fine but when i give it a punch of gas it will not even try to spin the tires it just kindof bogs down a little then takes off. I know it wont do anything special being a 267 and all but i know it can do more than this. Ive tried lots of things but i cant figure this one out, the only other thing i can think of is that it might be the torque convertor i put in. It was a used one i had layin around.
sounds more like a carb problem. what carb are you using? two or four barrel? cfm? vacuum secondaries or mechanical?
if its a holley, you might squirt in too much fuel from the little pump under the bowl. can be corrected by using a different colored plastic cam or/and a different size squirter (sits on top of the carb under choke plate in between 2 front barrels)
sounds more like a carb problem. what carb are you using? two or four barrel? cfm? vacuum secondaries or mechanical?
if its a holley, you might squirt in too much fuel from the little pump under the bowl. can be corrected by using a different colored plastic cam or/and a different size squirter (sits on top of the carb under choke plate in between 2 front barrels)
Daniel Doerksen
05-26-2005, 06:58 PM
yea.. most likely carb... if its 2 barel ...then thats ur problem :) if its 4 and a stock carb.. geting a holley it will help.. the problem with the stock carbs is the secondarys are way bigger then the primarys... so u get good fuel economy when u need it but when u wwant power it "can" bog because too much gas is dumped into the engine..
thats what i believe..
a solution miught be to delay when ur secondays kick in... oooo and one more thing.. on my 69caprice i put a 350 in it.. and it was out of a 79pickup which on had 170hp from factory.. but my car accels so damn slow.. i just couldnt believe how slow it was off the line... anyway to the point i had a 2.53 gears in my rearend when highways gears are 3.08s and factory gm i believe is 3.73
i put 4.10s in her and she slides sideways:) just an idea
thats what i believe..
a solution miught be to delay when ur secondays kick in... oooo and one more thing.. on my 69caprice i put a 350 in it.. and it was out of a 79pickup which on had 170hp from factory.. but my car accels so damn slow.. i just couldnt believe how slow it was off the line... anyway to the point i had a 2.53 gears in my rearend when highways gears are 3.08s and factory gm i believe is 3.73
i put 4.10s in her and she slides sideways:) just an idea
81firebird
05-26-2005, 10:24 PM
Im runnin a rochester dualjet (2bbl) and its 210 cfm. I bought it rebuilt.
volkerc
05-27-2005, 08:11 AM
Im runnin a rochester dualjet (2bbl) and its 210 cfm. I bought it rebuilt.
no offense, but all this does not sound like a tire chirpin combo. nevertheless, i would say your cam is trying to pull in more air due to higher lift, but is restricted by the 2 barrel carb.which is one problem. i still believe your carb gets either too much fuel, or not enough upon acceleration from a standing start. carbs spray in a bit more fuel into the manifold upon a standing start trough a small pump and suirters. lets say you are not getting enough fuel to burn to get the car going, the car will bog, until gravity will pull enough fuel through the open butterflys, causing a hesitation until you get the fuel that your engine needs to get going. the other it gets to much dumped into the carb, so that the engine can't burn it fast enough, causing the engine to be flooded more or less, and it will slow down the car, until the gas got burned, speed picked up and the ratio evened out. i installed a gauge in my car to see the air/fuel mixture at all times, so i have it easy to adjust the carb, and see if the car runs rich or lean, nice thing to have. i'd start in your case by checking the mixture. another easy check is to see if you "smell gas". A very overly rich mixture can be spotted by some odor also...and of cause blue smoke from the exhaust.
another thing to consider is, you are running a 3500 pound car with a small engine, so, course it will be somewhat slow compared to others...
a different rear gear would improve that situation as suggested by others, but what you gain on one end, you will lose on the other. a 4.10 ratio will be quick on the street, but bad on the highway and for fuel milage. a 2.56 or something will be slow on the street, but good on the highway, so going somwhere into the 3's might aid you. but you need to find out what you already have before spending money on gears.
no offense, but all this does not sound like a tire chirpin combo. nevertheless, i would say your cam is trying to pull in more air due to higher lift, but is restricted by the 2 barrel carb.which is one problem. i still believe your carb gets either too much fuel, or not enough upon acceleration from a standing start. carbs spray in a bit more fuel into the manifold upon a standing start trough a small pump and suirters. lets say you are not getting enough fuel to burn to get the car going, the car will bog, until gravity will pull enough fuel through the open butterflys, causing a hesitation until you get the fuel that your engine needs to get going. the other it gets to much dumped into the carb, so that the engine can't burn it fast enough, causing the engine to be flooded more or less, and it will slow down the car, until the gas got burned, speed picked up and the ratio evened out. i installed a gauge in my car to see the air/fuel mixture at all times, so i have it easy to adjust the carb, and see if the car runs rich or lean, nice thing to have. i'd start in your case by checking the mixture. another easy check is to see if you "smell gas". A very overly rich mixture can be spotted by some odor also...and of cause blue smoke from the exhaust.
another thing to consider is, you are running a 3500 pound car with a small engine, so, course it will be somewhat slow compared to others...
a different rear gear would improve that situation as suggested by others, but what you gain on one end, you will lose on the other. a 4.10 ratio will be quick on the street, but bad on the highway and for fuel milage. a 2.56 or something will be slow on the street, but good on the highway, so going somwhere into the 3's might aid you. but you need to find out what you already have before spending money on gears.
bigbadta
05-27-2005, 10:08 AM
Gotta couple of pontiac 400s n matching trannys
to make that thing what it oughta be,
if your interested
to make that thing what it oughta be,
if your interested
MrPbody
05-27-2005, 12:21 PM
bigbadta is correct. A 400 will certainly wake that car up beyond any reasonable street small block. The 267 IS the power problem. No offense intended, but those engines wouldn't turn the tires over in a Monza, much less a 3,800 lb. F-body.
Adding a big cam to a 2-bbl. engine is another big mistake. Don't feel bad, you aren't the first to make it, nor will you be the last.
Ignore all the buzzing in your ears from "buddies" that tell you you MUST use a Chevy to make it go. we recently had a pump gas (93 octane, no adders), flat tappet cammed 461 Poncho go 10.58 @ 127 in "street" trim. That was in a '70 Firebird.
If you're stuck on the Chevy, use a 383 or 400SB, if you want it to really perform. A BBC would do it, too.
Adding a big cam to a 2-bbl. engine is another big mistake. Don't feel bad, you aren't the first to make it, nor will you be the last.
Ignore all the buzzing in your ears from "buddies" that tell you you MUST use a Chevy to make it go. we recently had a pump gas (93 octane, no adders), flat tappet cammed 461 Poncho go 10.58 @ 127 in "street" trim. That was in a '70 Firebird.
If you're stuck on the Chevy, use a 383 or 400SB, if you want it to really perform. A BBC would do it, too.
Daniel Doerksen
05-27-2005, 12:37 PM
hmm.. hes right for the most part.. but easy where u lay the hits on chevy... cubic inches is always the best way to get power... take dodges leaning tower off power.. the slant 6.. all im saying is sure big enigones are good.. but. there are things tht can be done to 267.. so it can smkoke the wheels..
new heads.. 4barrel and i tihnk he would have plenty of power.. bang for buck anyway.. in whihc case if u got money and sum time.. and u wanna have alot of power.. 400smblock.. would be verynice.. if u built it up
new heads.. 4barrel and i tihnk he would have plenty of power.. bang for buck anyway.. in whihc case if u got money and sum time.. and u wanna have alot of power.. 400smblock.. would be verynice.. if u built it up
volkerc
05-27-2005, 12:42 PM
agree with all of you, but member 81firebird, has what he has. and if everybody had the money and all resources like some i'm sure he would have used something different, lets all help him the best with this combo, so he can get it going...
Automotive Network, Inc., Copyright ©2026