396 rochester carb - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mikewarme · 04-25-2011, 08:46 PM

I bought a rebuilt carb for my 396 a year ago. Finally got around to getting the truck running after paint etc. The carb is bad due to a crack in the body where the plugs for the primary jets are. Rather than getting another one thats the same , does anybody object to using say a 75 rochester that fit a 350 or 400 cu? My concern is that the 400 was a small block and even though the carb mounts will it perform fine? Otherwise im going to just order the correct one from Classic industries for a 69 like it came with. I want economy more than performance. Mileage is a factor here
Mike

**tkeduk8r** · 04-25-2011, 08:51 PM

another main body will work as well as long as it has the same early linkage, but youll get different stamping numbers and im not sure how detail oriented on this build you are.... if your looking for mileage the later castings are in my opinion a bit better and if you match your main and secondary jets with the right needles you can get a very efficient carb that if tuned well can nearly match a modern TBI setup.... just my experience.. hope that helps...
--Mike

Wrenchbender Ret · 04-26-2011, 03:45 PM

I prefer the late 70's early 80's Q-jets. They have the round choke & if it is not electric you can put the elec. choke coil in it. Like Tke says you can match the pri. jets & adjust the sec. air valves if ness. but generally they run fine as is.

04-25-2011, 08:46 PM	#1
mikewarme Registered User Join Date: Oct 2009 Location: Burbank,California Posts: 285	396 rochester carb I bought a rebuilt carb for my 396 a year ago. Finally got around to getting the truck running after paint etc. The carb is bad due to a crack in the body where the plugs for the primary jets are. Rather than getting another one thats the same , does anybody object to using say a 75 rochester that fit a 350 or 400 cu? My concern is that the 400 was a small block and even though the carb mounts will it perform fine? Otherwise im going to just order the correct one from Classic industries for a 69 like it came with. I want economy more than performance. Mileage is a factor here Mike

04-25-2011, 08:51 PM	#2
tkeduk8r Senior Member Join Date: Apr 2001 Location: Alexandria, MN Posts: 1,462	Re: 396 rochester carb another main body will work as well as long as it has the same early linkage, but youll get different stamping numbers and im not sure how detail oriented on this build you are.... if your looking for mileage the later castings are in my opinion a bit better and if you match your main and secondary jets with the right needles you can get a very efficient carb that if tuned well can nearly match a modern TBI setup.... just my experience.. hope that helps... --Mike __________________ 63 C20 2WD, 230/SM420/4.11 73K 68 C30 dump truck, 327,SM425,4.56 66K original 68 C10 2WD SWB Stepper, 250/3-tree/3.73 66K.... Wifes 68 Buick Skylark Custom Conv., 350/TH400/2.56 In our family since '79 69 GMC 1500 SWB 2WD, 350/TH350/3.73 posi... 70 K10 SWB 4X4 4-sp,ps, pb, tilt, buckets, console, sliding back window (Need AC parts) WIP 72 Chevy K20 4x4 350/350/205/4.56 donor 72 Vette 350/M21/3.70 posi, triple black and super fast 84 Olds Cutlass Brougham 350/2004r/4.11 was Dad's

04-26-2011, 03:45 PM	#3
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,226	Re: 396 rochester carb I prefer the late 70's early 80's Q-jets. They have the round choke & if it is not electric you can put the elec. choke coil in it. Like Tke says you can match the pri. jets & adjust the sec. air valves if ness. but generally they run fine as is.



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