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super72bb · 03-21-2004, 08:14 PM

I have a stock 402 BB and I am changing the intake manifold to a earlier style factory intake, the high rise type off of a 396. My goal is to keep the factory look to the truck but because the carb sits up about 2" higher I am running into a couple of issues.

The first thing I am finding is the factory heat riser tube is to short now which is no problem I can add a short section of pipe in there to make it fit. (Can anyone tell me if there was in fact a heat riser tube on the 396 trucks from the factory?) I haven't been able to locate one.

The biggest thing I need help with is. The choke mechanism. I am not exactly sure but I think it was the 67-68 years they used a manual choke. However, I was curious to know if there was a year when they didn't use a manual choke with the high rise style intake and started using the same sort of style of choke like on my 402.

I am planning to get a refurbished carb. So I was wondering if you can suggest a 396 carb and choke setup that I should use to best fit my application now. I was thinking a 1969 carb and choke assembly will work but I dont know if my throttle cable off the 72 will work. The supplier for the carb and choke assembly list's a different part # for all years for the Big Blocks 68-72 so I do have a good supply to choose from. I just need to order the right one.

Thanks Curt

**Joesjunk** · 03-21-2004, 10:40 PM

I have a 1969 factory 396 parts truck out here. It does not have a heat riser tube or a place for one. The air cleaner is a little different also. It has the high rise intake you are talking about also. I can take a pic of it if you need one.
Joe

super72bb · 03-21-2004, 10:55 PM

Hey Joe

If you wouldn't mind snapping a couple of pictures for me I sure would appreciate it. Really would like to see the air cleaner and the choke.

Thank you

Curt

**GSFMECH** · 03-21-2004, 11:10 PM

I have never seen a BB with a manual choke unless it was in a big truck, all that I have seen with that manifold were set up for an automatic choke. That hi rise style manifold likely came off a car. There should be a pad on the pass. side to attach a bi metal type choke mechanism with screws. Most of the Chevelle/ Camaro suppliers such as OPG, Classic Industries, The Paddock etc. offer a choke kit that comes with the bi metal "spring" and linkage. I would try to locate a Q-jet off a late 396 (67-68 or so) and you should have no trouble hooking one of these kits up but I would think any of the early Q-jets would work, just check the mounting flange. Some of those early Q-jets had different vacuum passages than our model trucks and may not mate up properly unless you do a little juggling with different style gaskets. Sorry I can't help with the pipe.

**breeh** · 03-22-2004, 01:43 AM

Here is a factory 68 396. You should be able to see the choke and the air cleaner. As stated earlier, no heat riser on this generation and automatic choke.

**GSFMECH** · 03-22-2004, 02:05 AM

Great shot breeh, that is just the thing I was talking about. See that square box just under the carb with the linkage attached. That has a bi metal "spring" in there. When the engine is cold ( before you start the engine) you push the the throttle wide open and the spring sets the choke and also steps the throttle up on a cam on the carb linkage to idle higher (adjustable on the right side of the carb). As the engine warms up the spring will expand and when it is warm enough you just blip the throttle and it will idle down and the choke will open, hence "automatic choke". That kit with bimetal spring and linkage is available from the aftermarket, the only thing I have never found is the square cover there in the picture but could be availible now days, been awhile since I was looking for one.

super72bb · 03-22-2004, 02:28 AM

Thats great... thank you guys!!! my

is over!

Curt

super72bb · 03-23-2004, 12:06 AM

Here is a picture of my new Older style high rise intake.

super72bb · 03-23-2004, 12:07 AM

here is one of my old intake

super72bb · 03-23-2004, 12:07 AM

one of the carb that came off the old intake

super72bb · 03-23-2004, 12:15 AM

I have no idea how you might tell but...

Does this carb look like it would be compatible with the new high rise? What makes me a bit unsure is the carb base on the high rise is different than that of the original 402 intake. Of course the carb does bolt right up but, there is a recessed area in front of the primary holes that is different on the high rise.

Thanks

**GSFMECH** · 03-23-2004, 01:15 AM

super72bb,
It would be best if you could find the right carb, those early Q-jets had that funky vacuum passage going across the front just ahead of the primarys. 65streetcruiser and I just went through this same ordeal with a 68 327, it also should have the same carb as your hi rise type manifold uses, but as you we also had a later one similar to yours that we wound up using. I think if you have a good parts man that will let you juggle around all the different gaskets that were available you should be ok using this carb. The trick is to get that forward passage sealed off so you have no vacuum leaks. We were able to match up one for the 327 I mentioned, I think we used a gasket that had only the 4 holes for the carb bores if memory serves me. In the old days you used to be able to get a multi gasket set with several aluminum plates/gaskets that were used as insulators, I think Mr Gasket made them. I have had good luck using that set too. You will just have to do some careful gasket matching. Oh and you should be able to get the choke stat (bi metal spring) from the parts store too, all you will need then is the linkage. I mentioned the ones from the aftermarket last night because they are handy as they have the linkage too. You could make the linkage if you had to. I see you have a old one on the low rise manifold and it will not be the same as the one you will need for the hi rise (the mounting hole is in a different place). Sorry I can't help more but I really think you can make it work with the right gasket.

Mike

super72bb · 03-23-2004, 02:52 AM

Thanks again Mike.

Curt

JimKshortstep4x4 · 03-23-2004, 09:56 AM

I plugged the two holes in the high rise intake manifold for my 66
Impala, by tapping them out with a 1/4" pipe tap. Exhaust circulates through the holes and the channel and it can be a pain to seal for very long. If you don't plug them get a stainless steel plate plate to cover the channel as aluminum will not last.

Jim

03-21-2004, 08:14 PM	#1
super72bb Senior Member Join Date: Jan 2002 Location: calgary,Alberta,Canada Posts: 387	Ok Big Block Guru's I have a stock 402 BB and I am changing the intake manifold to a earlier style factory intake, the high rise type off of a 396. My goal is to keep the factory look to the truck but because the carb sits up about 2" higher I am running into a couple of issues. The first thing I am finding is the factory heat riser tube is to short now which is no problem I can add a short section of pipe in there to make it fit. (Can anyone tell me if there was in fact a heat riser tube on the 396 trucks from the factory?) I haven't been able to locate one. The biggest thing I need help with is. The choke mechanism. I am not exactly sure but I think it was the 67-68 years they used a manual choke. However, I was curious to know if there was a year when they didn't use a manual choke with the high rise style intake and started using the same sort of style of choke like on my 402. I am planning to get a refurbished carb. So I was wondering if you can suggest a 396 carb and choke setup that I should use to best fit my application now. I was thinking a 1969 carb and choke assembly will work but I dont know if my throttle cable off the 72 will work. The supplier for the carb and choke assembly list's a different part # for all years for the Big Blocks 68-72 so I do have a good supply to choose from. I just need to order the right one. Thanks Curt __________________ 1972 CHEYENNE SUPER SWB BLACK. 402 BB, TH400, AIR, TILT, TACH, BUCKETS, CRUISE, AM/FM, 8 TRACK. My build thread: http://67-72chevytrucks.com/vboard/s...=1#post7120181

03-21-2004, 10:40 PM	#2
Joesjunk Senior Member Join Date: May 2001 Location: Independence MO. Posts: 7,689	I have a 1969 factory 396 parts truck out here. It does not have a heat riser tube or a place for one. The air cleaner is a little different also. It has the high rise intake you are talking about also. I can take a pic of it if you need one. Joe __________________ 72 3/4t Custom Deluxe 402/auto 66k Original paint 71 3/4t 4x4 Custom Deluxe 10k original miles Original paint 71 3/4t Cheyenne 402 70k original paint 72 3/4t 4x4 Custom deluxe 72 3/4t 4x4 Custom deluxe 91k original paint 72 Cheyenne/30 Dually 69 Camaro SS396 4-speed 13 GMC 2500HD Duramax I bought new 05 Jeep Wrangler "Willys Edition" 12k miles (I bought new) 85 3/4 ton 4x4 Scottsdale 33k miles original paint 86 1 ton 4x4 SRW Silverado 454 restored 80 1 ton 4x4 SRW Silverado 9,434 original miles!! original paint 95 GMC 1 ton dually 4x4 my dad bought new 95 GMC 3/4 ton 4x4, regular cab 454, 31k original miles 2002 2500HD 4x4 regular cab 6.0L 67k miles 2002 2500HD 4x4 regular cab 8.1L 28k miles 2003 GMC 2500HD 4x4 regular cab Diesel 93k miles 67-72 Parts for sale

03-21-2004, 10:55 PM	#3
super72bb Senior Member Join Date: Jan 2002 Location: calgary,Alberta,Canada Posts: 387	Hey Joe If you wouldn't mind snapping a couple of pictures for me I sure would appreciate it. Really would like to see the air cleaner and the choke. Thank you Curt __________________ 1972 CHEYENNE SUPER SWB BLACK. 402 BB, TH400, AIR, TILT, TACH, BUCKETS, CRUISE, AM/FM, 8 TRACK. My build thread: http://67-72chevytrucks.com/vboard/s...=1#post7120181

03-22-2004, 01:43 AM	#5
breeh Recovering 67-72 Addict Join Date: Oct 2000 Location: North Bend, WA Posts: 1,788	Here is a factory 68 396. You should be able to see the choke and the air cleaner. As stated earlier, no heat riser on this generation and automatic choke. Attached Images __________________ 68 Short Fleet 4x4; 427; BTO Level 3 700R4; NP205; Dana 60 front and rear; 4" lift with 35's; Disc brakes; AGR variable ratio steering; factory bucket seats; factory tach and tilt. "Friends call me cruzer cuz I like fast cars and fast women"

03-22-2004, 02:28 AM	#7
super72bb Senior Member Join Date: Jan 2002 Location: calgary,Alberta,Canada Posts: 387	Thats great... thank you guys!!! my is over! Curt __________________ 1972 CHEYENNE SUPER SWB BLACK. 402 BB, TH400, AIR, TILT, TACH, BUCKETS, CRUISE, AM/FM, 8 TRACK. My build thread: http://67-72chevytrucks.com/vboard/s...=1#post7120181

03-21-2004, 11:10 PM	#4
GSFMECH On the road Join Date: Jan 2004 Location: NATCHITOCHES LOUISIANA Posts: 812	I have never seen a BB with a manual choke unless it was in a big truck, all that I have seen with that manifold were set up for an automatic choke. That hi rise style manifold likely came off a car. There should be a pad on the pass. side to attach a bi metal type choke mechanism with screws. Most of the Chevelle/ Camaro suppliers such as OPG, Classic Industries, The Paddock etc. offer a choke kit that comes with the bi metal "spring" and linkage. I would try to locate a Q-jet off a late 396 (67-68 or so) and you should have no trouble hooking one of these kits up but I would think any of the early Q-jets would work, just check the mounting flange. Some of those early Q-jets had different vacuum passages than our model trucks and may not mate up properly unless you do a little juggling with different style gaskets. Sorry I can't help with the pipe.

03-22-2004, 02:05 AM	#6
GSFMECH On the road Join Date: Jan 2004 Location: NATCHITOCHES LOUISIANA Posts: 812	Great shot breeh, that is just the thing I was talking about. See that square box just under the carb with the linkage attached. That has a bi metal "spring" in there. When the engine is cold ( before you start the engine) you push the the throttle wide open and the spring sets the choke and also steps the throttle up on a cam on the carb linkage to idle higher (adjustable on the right side of the carb). As the engine warms up the spring will expand and when it is warm enough you just blip the throttle and it will idle down and the choke will open, hence "automatic choke". That kit with bimetal spring and linkage is available from the aftermarket, the only thing I have never found is the square cover there in the picture but could be availible now days, been awhile since I was looking for one.

03-23-2004, 12:06 AM	#8
super72bb Senior Member Join Date: Jan 2002 Location: calgary,Alberta,Canada Posts: 387	Here is a picture of my new Older style high rise intake. Attached Images __________________ 1972 CHEYENNE SUPER SWB BLACK. 402 BB, TH400, AIR, TILT, TACH, BUCKETS, CRUISE, AM/FM, 8 TRACK. My build thread: http://67-72chevytrucks.com/vboard/s...=1#post7120181

03-23-2004, 12:07 AM	#9
super72bb Senior Member Join Date: Jan 2002 Location: calgary,Alberta,Canada Posts: 387	here is one of my old intake Attached Images __________________ 1972 CHEYENNE SUPER SWB BLACK. 402 BB, TH400, AIR, TILT, TACH, BUCKETS, CRUISE, AM/FM, 8 TRACK. My build thread: http://67-72chevytrucks.com/vboard/s...=1#post7120181

03-23-2004, 12:15 AM	#11
super72bb Senior Member Join Date: Jan 2002 Location: calgary,Alberta,Canada Posts: 387	I have no idea how you might tell but... Does this carb look like it would be compatible with the new high rise? What makes me a bit unsure is the carb base on the high rise is different than that of the original 402 intake. Of course the carb does bolt right up but, there is a recessed area in front of the primary holes that is different on the high rise. Thanks __________________ 1972 CHEYENNE SUPER SWB BLACK. 402 BB, TH400, AIR, TILT, TACH, BUCKETS, CRUISE, AM/FM, 8 TRACK. My build thread: http://67-72chevytrucks.com/vboard/s...=1#post7120181

03-23-2004, 01:15 AM	#12
GSFMECH On the road Join Date: Jan 2004 Location: NATCHITOCHES LOUISIANA Posts: 812	super72bb, It would be best if you could find the right carb, those early Q-jets had that funky vacuum passage going across the front just ahead of the primarys. 65streetcruiser and I just went through this same ordeal with a 68 327, it also should have the same carb as your hi rise type manifold uses, but as you we also had a later one similar to yours that we wound up using. I think if you have a good parts man that will let you juggle around all the different gaskets that were available you should be ok using this carb. The trick is to get that forward passage sealed off so you have no vacuum leaks. We were able to match up one for the 327 I mentioned, I think we used a gasket that had only the 4 holes for the carb bores if memory serves me. In the old days you used to be able to get a multi gasket set with several aluminum plates/gaskets that were used as insulators, I think Mr Gasket made them. I have had good luck using that set too. You will just have to do some careful gasket matching. Oh and you should be able to get the choke stat (bi metal spring) from the parts store too, all you will need then is the linkage. I mentioned the ones from the aftermarket last night because they are handy as they have the linkage too. You could make the linkage if you had to. I see you have a old one on the low rise manifold and it will not be the same as the one you will need for the hi rise (the mounting hole is in a different place). Sorry I can't help more but I really think you can make it work with the right gasket. Mike

03-23-2004, 02:52 AM	#13
super72bb Senior Member Join Date: Jan 2002 Location: calgary,Alberta,Canada Posts: 387	Thanks again Mike. Curt __________________ 1972 CHEYENNE SUPER SWB BLACK. 402 BB, TH400, AIR, TILT, TACH, BUCKETS, CRUISE, AM/FM, 8 TRACK. My build thread: http://67-72chevytrucks.com/vboard/s...=1#post7120181

03-23-2004, 09:56 AM	#14
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	I plugged the two holes in the high rise intake manifold for my 66 Impala, by tapping them out with a 1/4" pipe tap. Exhaust circulates through the holes and the channel and it can be a pain to seal for very long. If you don't plug them get a stainless steel plate plate to cover the channel as aluminum will not last. Jim



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