| FAQ |
| Members List |
| Social Groups |
| Calendar |
| Search |
| Today's Posts |
|
#1
05-14-2026, 10:11 PM
|
|||
|
|||
1977 Pontiac 400 #62 heads 2801 cam
Just replaced my Saginaw 4 speed with a Muncie and a set of head gaskets and trying to find a good spot for the timing. Drive it for a bit and seemed to have some detonation under acceleration so I put 5 gal of e 85 and 4 gal of 89 in it trying to get about 95 still seemed like a little detonation so went to back of the timing but she is running like **** ( was before the e-85) the idle is all over trying to adjust it doesn’t really help. As it is so sporadic at idle. I tried to post video but it won’t let me
|
|
#2
05-15-2026, 04:36 AM
|
||||
|
||||
|
What year carb is on the motor,
A Q-jet from 1977 or one from 1969 like the heads ? Do you even know how much inital timing you have now ? On your balancer make a line 2 1/8” away from TDC, that will be 36 degrees more or less, then check your timing with the vacuum advance off and plugged off and report back on what you have. If the carb you have had sat with fuel in it for more then 6 months then it likely gummed up and will need to be gone thru.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
|
#3
05-15-2026, 06:00 AM
|
||||
|
||||
|
One other suggestion, the higher percent of ethanol will need to increase jetting because it will be very lean.
__________________
John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! W.E.C moment "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
|
#4
05-15-2026, 12:08 PM
|
||||
|
||||
|
I have the 2801 in a 6X-4 headed 400 and a pretty smooth idle.
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune [email protected] 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs 1964 Corvette Coupe 327 4 speed |
|
#5
05-15-2026, 12:21 PM
|
|||
|
|||
|
I would have put 91-93 instead of e85.Tom
|
| The Following User Says Thank You to tom s For This Useful Post: | ||
|
#6
05-15-2026, 06:29 PM
|
||||
|
||||
|
Check total timing. Should be around 36 degrees fully in, without vacuum advance hooked up. If you have the original beveled top pistons that came in a 77' 400, with the #62 heads, I would think you only have around 9.5 CR. It SHOULD run on 93 octane with no issues. What temperature is the engine running?
__________________
62' Lemans, Nostalgia Super Stock, 541 CI, IA2 block, billet 4.5" crank, Ross, Wide port Edelbrocks, Gustram intake, 2 4150 style BLP carbs, 2.10 Turbo 400, 9" w/4:30 gears, 8.76 @153, 3100lbs |
|
#7
05-15-2026, 06:35 PM
|
|||
|
|||
|
Yeah, I tried to set the timing, but the idol was so sporadic. I figured I need to get a smoother idol or setting the timing. someone sent me their number. I’d send you the video of it running. You might be able to provide me with a little better answers cause it won’t let me posted it on here for some reason.
|
|
#8
05-15-2026, 06:51 PM
|
||||
|
||||
|
If you manually slowly close down the choke with the motor at hot idle do things smooth out or does it want to stall out even worse?
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
| Reply |
|
|
The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.
Linear Mode
