New air-gap manifold and custom/rebuilt q-jet. Sounds good but I still need to set the timing on the distributor and the carb is tuned already. Hope you like, nothing to fancy just a few revs and walk around...the Exhaust is true dual no x/h pipe and it has cherry bomb glasspacks(3 inch)
how to minimize engine bog with a Quadrajet carb
this is to minimize engine bog when the pedal is to the metal. do not over
tighten, very small spring...you want to try 1/4 turns or 1/2...q-jets are
good if tuned properly. also when you are tightening screw it will have
tension on it so keep the screwdriver firm. 1986 gmc sierra single
straightpipe to cherrybomb. you will need a small flathead screwdriver and
a 3/32 allen key. be sure not to tighten to much or else your vacuum
secondary flaps wont open.
Rochester Quadrajet, the results!
Two mishaps, the first shown here, the choke coil I got was wound
backwards, it made the choke butterfly wind up TIGHTER as the engine warmed
up. I swapped on the one from the old carburetor fast enough, the second
mishap made me feel like a crud and what did I mess up later that evening.
The car would not start leaving the Etobicoke -Queensway show. It was not
getting gas. We got it running by priming the carburetor, and boy, was I
ticked at myself. In the end it was not my fault it looks like. The new
accelerator pump umbrella and rod was a very poor and frail design, the
umbrella came detached and stayed at the bottom of the of the pump well,
and was a distressed mess. The maker will get a note from me. The upshot?
The old assembly went in, all is perfectly fine, the slight tip-in
hesitation is gone now too. Stupid lack of pride it seems these days
making parts for even simple things like an old carburetor.
Decoding a Rochester Quadrajet part 1: The name
Rochester Quadrajets tend to mystify people because of the various model
names assigned to them by GM.
Add to that a redesign in the '70s and the confusion only grows.
In this video we'll learn the different model names and also how to
differentiate between early and later-model Qjets. Enjoy!
'77 Chevy K20: Quadrajet Choke Pull Off and Fast Idle Cam Observations
1977 Chevy K20. 350 crate engine. Rochester Quadrajet 4MV carburetor with
Truck suffers from unexplained hesitation and bogging when in forward
gears. Tends to rev just fine after a few minutes of mixed idling and high
revving. Checking choke operations as well as a possible sticky fast idle
cam as part of the process of elimination.
- Truck is allowed to idle/warm up until 2:25 mark, at which point the
engine is revved to about 2,000 rpm, and can be heard bogging (a hissing
sound can be heard). The fast idle cam is seen dropping. Fuel flow can be
seen in the glass-cased fuel filter right before the carb as remaining
- The engine is revved again about three more time up until 3:00 minute
mark. The engine revs slightly higher, but the hissing and bogging can
still be heard.
- Engine is revved again at the 3:35 mark, slightly past the 3,000 rpm
mark. Hesitation and hissing still evident, but less so than before.
- Engine revved at the 4:25 mark to about 4,000 rpm. No hesitation or
- Transmission is slowly shift through every gear starting at 4:55 mark.
Shifted back into Park at 5:05 mark.
- Engine revved again at 5:10 and 5:17 marks to 4,000 rpm. No hesitation or
hissing is heard.
To read up on the discussion, please visit the following thread:
See 1976 Chevrolet pickup with Rochester quadrajet upgrade on SBC 350 V8.
We removed the hood, mounted a camera looking down on the air horn, and
took it for a spin, running wide open on an uphill grade. See how the
secondary air valve responds to rpm drop at each upshift of the THM. Also
included is a smoking burnout.