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Buy Quadrajet Parts, Quadrajet Kits, Service / Re: carb suggestion for Cadillac 425 and 500
« Last post by Cliff Ruggles on Today at 12:17:24 AM »
Yes, the 17057530 would be the best carb to use.

No need to re-jet when swapping it back and forth.  Make sure to provide access to the APT screw.  I would tap the airhorn and install a 3/8-16 set-screw so you can remove it for fine tuning if/as needed......Cliff
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Quadrajet Carb Talk and Tips / Re: Accel pump boot replacement
« Last post by Cliff Ruggles on Today at 12:14:52 AM »
Be very careful removing the ring you can crack or break the airhorn as it's very thin in that area.

I use a small thin screwdriver and gently pry them out.  You may have to grind one to a knife edge to get under it.

The accl pump is installed into the airhorn first, then the boot, then the retaining ring.  I use a hole punch to seat the ring but make sure you have excellent support under it before driving the ring down as it's easy to break the airhorn in that area.

I use a couple of blocks of wood under the airhorn and gently tap the ring in place.....Cliff
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Quadrajet Carb Talk and Tips / Accel pump boot replacement
« Last post by eric65 on April 22, 2019, 05:58:33 PM »
Hi new here but lurker for a bit

Have my Cliff kit but trying to figure how to replace the Accel pump boot and retainer.  Old boot ripped a bit so I pulled it out.   There's a ring in the well but cant figure if it comes out or not or if it does come out how?
Then how to install the new one??

Thanks for any help

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Quadrajet Carb Talk and Tips / Re: 350 having detonation problems.
« Last post by tayto on April 22, 2019, 07:44:02 AM »
The TBI heads like 28-30* TOTAL timing. It sounds like you are running the "old school" 36* total timing if I am reading it right...
The TBI heads are very efficient cylinder head it just sounds like you are throwing to much timing at them? I am building an engine similar to yours 191 heads, 10:1 static compression, running a TPI cam 202/207 @. 050 " 114.5* LSA with 1.7 roller rockers . Sounds like i should goto a bigger cam as well....
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Quadrajet Carb Talk and Tips / Re: 350 having detonation problems.
« Last post by Cliff Ruggles on April 22, 2019, 04:27:15 AM »
Move up to the 214/224/112 cam and it will lower dynamic compression close to 1 point.

Another option is to simply retard the timing till it doesn't ping.

Decades ago I built a 400 SBC with flat top pistons and 76cc heads and installed a small cam in it.

Had to run the initial timing down around 4 degrees and total at 26, but it ran over 100,000 miles and made TONS of power everyplace.  I also added 8 degrees from the vacuum advance.

The engine was in a 1979 K-5 Blazer, TH350, 3.07 rear gears and 32" tall tires.  It was one of the best running engines I've ever owned, and got excellent fuel economy as well.  I knocked down 13-14 for normal driving and 15-17 on the highway.  I could tow anything with it, the torque production was excellent.......Cliff
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Quadrajet Carb Talk and Tips / Re: 350 having detonation problems.
« Last post by Greasy Harley on April 20, 2019, 11:52:40 PM »
Been doing some research.
I currently have this cam:
https://www.summitracing.com/parts/mel-mtc-1
was thinking this one might do the trick:
https://www.summitracing.com/parts/mel-22215
Maybe this one?
https://www.summitracing.com/parts/sum-1103
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Quadrajet Carb Talk and Tips / Re: 350 having detonation problems.
« Last post by Greasy Harley on April 20, 2019, 06:10:11 PM »
Quote from: Greasy Harley on April 20, 2019, 04:07:24 PM
.... Problem is, I have my timing retarded to 8* initial, and 28* mechanical and still have slight detonation around 3500-3800 RPM's -I have to estimate because I don't have a tach.
...
I should clarify, My timing is 8* initial, and 28* Total (not additional mechanical) with VA unhooked.;
There is an additional 12* VA on top of that, but I get the same detonation whether the VA is hooked up or not.
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Quadrajet Carb Talk and Tips / 350 having detonation problems.
« Last post by Greasy Harley on April 20, 2019, 04:07:24 PM »
Quote from: tayto on February 04, 2019, 06:04:12 PM
I just got my set of 191 TBI heads cc'd last week and they were 65 cc. 193 castings will be the same FYI. You may want to check your static compression again unless you've worked the combustion chamber then ignore me.
I thought for sure they were 72cc combustion chambers,

...So yeah, I think I miscalculated my compression ratio :o
Okay I rebuilt a 350
87 TBI block, .060 over, flat top slugs with 4 releifs
65cc TBI "191" heads, These heads are susceptible to detonation (I later learned)
10:1 compression
Compression test reads 185psi (rings aren't seated yet, about 200mi on engine)

I put a "torque cam" in it trying to make a good truck motor. Problem is, I have my timing retarded to 8* initial, and 28* mechanical and still have slight detonation around 3500-3800 RPM's -I have to estimate because I don't have a tach.

Cam specs are:
Elgine MTC-1
Intake Duration at 050 inch Lift: 204
Exhaust Duration at 050 inch Lift: 214
Duration at 050 inch Lift: 204 int./214 exh.
Advertised Intake Duration: 278
Advertised Exhaust Duration: 288
Advertised Duration: 278 int./288 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.420 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.433 in.
Valve Lift with Factory Rocker Arm Ratio: 0.420 int./0.438 exh.
Lobe Separation (degrees): 112


This motor doesn't like this cam, so my options seem to be,
1)decrease compression----> different heads with 72cc chambers I DON'T REALLY WANT TO SWAP HEADS
-Maybe thicker head gaskets?
..or

2)swap cams

I'm thinking I need a cam with around
Intake Valve Duration (degrees @ .050" lift) in the 220ish range to compensate for the high CR

I don't want to swap springs if I don't have to, and I would like to keep the RPM Power Range as low as possible.
anyone have any cam suggestions ?
Can I fix this problem with a simple cam swap?
Should I just buy different heads? ---Really don't want to.
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Buy Quadrajet Parts, Quadrajet Kits, Service / Re: carb suggestion for Cadillac 425 and 500
« Last post by caddylackn on April 19, 2019, 01:05:40 PM »
I ordered the SR kit for the 17057530, hope this works.
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Buy Quadrajet Parts, Quadrajet Kits, Service / carb suggestion for Cadillac 425 and 500
« Last post by caddylackn on April 18, 2019, 09:40:01 AM »
I would like to rebuild one carb to use on either my Cadillac 425 ci. or Cad 500 ci. motor.  I will run either engine in my '69 Chev. Truck Camper Special and occasionally have a cab over camper with a total 7,500 GVW.  Stock or mild cam, pocket ported heads, HEI, MSD 6A box, and headers.

I have a 17057530- from the CAD 425, number shows it is a Calif. model, electric choke
a 7043230 from the Cad 500- pretty dirty shape, divorced choke
a 17058204 currently in the truck atop a 350, electric choke

Which would be the best carb to rebuild?
Can I run the 425 carb on the 500 by just swapping in the 500 carb jets, secondary rods?
I am not required to run EGR in the '69 truck and wasn't planning on it.  Both Cad motors had EGR manifolds. Will I need jetting changes?

TIA
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