Hi All: Replacing my old 350 with a 6 cylinder out of a 72 Camaro. It had a powerglide but I am going to use my old thm 350. Question: re the vacuum modulator valve: where on the 6 cylinder do I attach the engine end of the tubing running from the transmission? On the 350 (was a Chevy 350) there was a dedicated spot for the tube on the intake manifold but I see nothing obvious on the 6 cylinder motor. Thanking you in advance....
72 lemans
- Thread starter Bill9167
- Start date
92 Sunbird LE
Well-known member
http://67-72chevytrucks.com/vboard/attachment.php?attachmentid=324530&stc=1&d=1198878358
In the pic you can see the rubber vacumn line from the carb to the back of the motor, so it comes off the carb base. ( one for trans , one for PCV , one for power brakes - if equipped , one for distributor) You need full vacumn for the trans ( not ported)
Or either add a "T" fitting to existing hose or drill and tap the manifold for a separate fitting.
Doug in P.R.
In the pic you can see the rubber vacumn line from the carb to the back of the motor, so it comes off the carb base. ( one for trans , one for PCV , one for power brakes - if equipped , one for distributor) You need full vacumn for the trans ( not ported)
Or either add a "T" fitting to existing hose or drill and tap the manifold for a separate fitting.
Doug in P.R.
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92 Sunbird LE
Well-known member
That truck in the pic does not have power brakes, so no hose is shown to it.
If you have power brakes in your Lemans , the 3/8ths hose to the PCV will do , just put a "T" close to the carb.
The trans needs a small hose to it . Just tap into a small hose off the carb with a "T".
Doug in P.R.
If you have power brakes in your Lemans , the 3/8ths hose to the PCV will do , just put a "T" close to the carb.
The trans needs a small hose to it . Just tap into a small hose off the carb with a "T".
Doug in P.R.
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thank you again
Got it. Thank you so much. Now, next question: I have the complete set of motor mounts for the 6 cylinder. I realise I must get the old v8 mounts off the frame and that is a frustrating and time consuming job. I would have thought that GM would have placed holes in the frame to accommodate the 6 cylinder mounts but I do not think they are there. Have you any experience with this? To reiterate, I am going from a 72 chevy 350, stock in my 72 Luxury Lemans to a 250 6 cylinder out of a 72 Camaro. Cheers.
Got it. Thank you so much. Now, next question: I have the complete set of motor mounts for the 6 cylinder. I realise I must get the old v8 mounts off the frame and that is a frustrating and time consuming job. I would have thought that GM would have placed holes in the frame to accommodate the 6 cylinder mounts but I do not think they are there. Have you any experience with this? To reiterate, I am going from a 72 chevy 350, stock in my 72 Luxury Lemans to a 250 6 cylinder out of a 72 Camaro. Cheers.
92 Sunbird LE
Well-known member
Holes should be there, 250 Chevy 6 was an option in 72.
The old school way is to bolt up the engine to the trans with both the frame mounts and motor mounts on the engine, center it up, set it down on the frame and spray paint the frame mounts on the frame with a color you see well. (including the holes on the frame mounts)
Then drill the holes or weld on the frame mounts.
Hope this helps................Doug in P.R.
The old school way is to bolt up the engine to the trans with both the frame mounts and motor mounts on the engine, center it up, set it down on the frame and spray paint the frame mounts on the frame with a color you see well. (including the holes on the frame mounts)
Then drill the holes or weld on the frame mounts.
Hope this helps................Doug in P.R.
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92 Sunbird LE
Well-known member
Found this Nova info ( same sub frame as Camaro ) swap guide L6 to V8 .
Engine Mounts
Since the extra length of the inline 6 engines (as compared to a V8) is in front of the engine mounts, there is no need to move the mounts forward during the engine swap. In other words, the mount-to-bellhousing distance is the same for both L6 and V8 engines.
1973 to 1979:
These years used an interlocking "clam shell" type engine mounts. The lower (frame halves) of these mounts consist of a rubber core surrounded by a metal shell. They are the same for both L6 and V8 engines and unless the rubber core is bad there is no need to even unbolt them from the frame when doing an engine swap in a 73-79 Nova. Some parts catalogs and local auto parts stores sell replacement frame-halves of these mounts. Replacement polyurethane cores are also available for use in the existing metal shells.
The engine halves of these mounts are "U" shaped steel brackets that are specific to the engine type (L6 or V8). Unlike the frame halves, these brackets are only available new through GM or used (salvage yard, parts vehicle, or such). The original GM number for these engine mounting brackets is 334970. Suitable donor cars for these engine mounting brackets include the following vehicles with a small block Chevy V8:
1973 - 1979 X-body (Nova)
1973 - 1977 A-body (Chevelle, ElCamino, GMC Sprint)
1973 - 1979 B-body (Impala, Caprice)
The 334970 engine mount bracket is also listed in the GM parts catalogs as fitting the LH side only on 1982 - 1989 F-body (Camaro). I'm not sure what is different about the RH mount on those cars but it may be a different height.
Note that many 73 - 90's GM rear wheel drive vehicles used very similar looking engine mounting brackets. However, the large through-bolt holes are located in slightly different positions on some of these mounts.
pre 1973:
These years used non-interlocking engine mounts (aftermarket interlocking replacements are available). The frame halves of these mounts (perches) are made of steel and the engine halves are made of steel/rubber. Both halves of these mounts are specific to the engine (L6, small block V8, or big block V8). Therefore, both halves need to be replaced during an engine swap. Most parts catalogs sell these type of mounts. The '73 & up "clam shell" type mounts will also retrofit into '68 - '72 Novas.
When doing an engine swap in a pre '73 car, the V8 frame halves (perches) will bolt into the same frame holes that were used by the L6 perches.
Note that there were two different engine mounts used on small block V8's during the 68-72 year range. They can be identified by measuring the width between the mounting ears that mate with the frame perch. I believe either style can be used for an engine swap so long as they're used along with the corresponding frame perches.
So, the L6 motor mounts should fit on the V8 frame perches currently in your car............
Doug in P.R.
Engine Mounts
Since the extra length of the inline 6 engines (as compared to a V8) is in front of the engine mounts, there is no need to move the mounts forward during the engine swap. In other words, the mount-to-bellhousing distance is the same for both L6 and V8 engines.
1973 to 1979:
These years used an interlocking "clam shell" type engine mounts. The lower (frame halves) of these mounts consist of a rubber core surrounded by a metal shell. They are the same for both L6 and V8 engines and unless the rubber core is bad there is no need to even unbolt them from the frame when doing an engine swap in a 73-79 Nova. Some parts catalogs and local auto parts stores sell replacement frame-halves of these mounts. Replacement polyurethane cores are also available for use in the existing metal shells.
The engine halves of these mounts are "U" shaped steel brackets that are specific to the engine type (L6 or V8). Unlike the frame halves, these brackets are only available new through GM or used (salvage yard, parts vehicle, or such). The original GM number for these engine mounting brackets is 334970. Suitable donor cars for these engine mounting brackets include the following vehicles with a small block Chevy V8:
1973 - 1979 X-body (Nova)
1973 - 1977 A-body (Chevelle, ElCamino, GMC Sprint)
1973 - 1979 B-body (Impala, Caprice)
The 334970 engine mount bracket is also listed in the GM parts catalogs as fitting the LH side only on 1982 - 1989 F-body (Camaro). I'm not sure what is different about the RH mount on those cars but it may be a different height.
Note that many 73 - 90's GM rear wheel drive vehicles used very similar looking engine mounting brackets. However, the large through-bolt holes are located in slightly different positions on some of these mounts.
pre 1973:
These years used non-interlocking engine mounts (aftermarket interlocking replacements are available). The frame halves of these mounts (perches) are made of steel and the engine halves are made of steel/rubber. Both halves of these mounts are specific to the engine (L6, small block V8, or big block V8). Therefore, both halves need to be replaced during an engine swap. Most parts catalogs sell these type of mounts. The '73 & up "clam shell" type mounts will also retrofit into '68 - '72 Novas.
When doing an engine swap in a pre '73 car, the V8 frame halves (perches) will bolt into the same frame holes that were used by the L6 perches.
Note that there were two different engine mounts used on small block V8's during the 68-72 year range. They can be identified by measuring the width between the mounting ears that mate with the frame perch. I believe either style can be used for an engine swap so long as they're used along with the corresponding frame perches.
So, the L6 motor mounts should fit on the V8 frame perches currently in your car............
Doug in P.R.
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unless this is a Canadian manufactured car, a Chevy 350 was not stock in 1972, it would have been a Pontiac 350. Just my 2 cents, putting a 6 in it will kill any resale value.
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92 Sunbird LE
Well-known member
I had to read it twice too, Mel. The" Cheers " made me think a minute , its a Canadian saying...........
We have a bunch on HBody board too.
Doug in P.R.
92 Sunbird LE
Well-known member
Canadian
Hi: Thank you ever so much for the info. I purchased the Luxury Lemans up here in Vancouver on 17 May, 1972. $4000 cash, including tax. It was my first and only car until 30 April 2009 and now is used for taking the dog to the dog park and hauling junk to the dump. Unfortunately, it has little re-sale value as the rust and dents have pretty well taken over. It most definitely had a chevy 350 in it. Many many times I had to return parts because the 15 year old parts guys refused to understand it was a chevy motor. Their parts books said blah blah blah and I ended up with Pontiac 350 bits and pieces. I digress. I am going to do my best to remove the frame mounts. They bear no resemblance to the engine and frame mounts I got with the motor. (I took the motor out of the 72 Camaro so I know they worked for it). For some reason, I just assumed it would be a very simple job putting the 6 cylinder mounts into pre-existing holes on the frame. Maybe it will be once I get the old mounts out but I do not think the holes will line up. The chevy 350 frame mounts have 4 bolts, the 250 mounts have 3 holes and there appear to be other differences. Let you know once the rain stops....no garage.
Cheers.
Hi: Thank you ever so much for the info. I purchased the Luxury Lemans up here in Vancouver on 17 May, 1972. $4000 cash, including tax. It was my first and only car until 30 April 2009 and now is used for taking the dog to the dog park and hauling junk to the dump. Unfortunately, it has little re-sale value as the rust and dents have pretty well taken over. It most definitely had a chevy 350 in it. Many many times I had to return parts because the 15 year old parts guys refused to understand it was a chevy motor. Their parts books said blah blah blah and I ended up with Pontiac 350 bits and pieces. I digress. I am going to do my best to remove the frame mounts. They bear no resemblance to the engine and frame mounts I got with the motor. (I took the motor out of the 72 Camaro so I know they worked for it). For some reason, I just assumed it would be a very simple job putting the 6 cylinder mounts into pre-existing holes on the frame. Maybe it will be once I get the old mounts out but I do not think the holes will line up. The chevy 350 frame mounts have 4 bolts, the 250 mounts have 3 holes and there appear to be other differences. Let you know once the rain stops....no garage.
Cheers.
92 Sunbird LE
Well-known member
A grinder with a cut off wheel will make quick work of the bolt heads on top to save you time trying to get them apart underneath.............
Doug in P.R.
Doug in P.R.
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grinder
Thanks Doug: Yes, that will get the bolts out but I still need to get into the frame to fasten the new bolts in place. I do not weld well. Is there some type of self-locking bolts that could be safely used to anchor the motor? I am thinking there should be nuts attached as there are now. I sincerely appreciate all your help. Cheers.
A grinder with a cut off wheel will make quick work of the bolt heads on top to save you time trying to get them apart underneath.............
Doug in P.R.
Thanks Doug: Yes, that will get the bolts out but I still need to get into the frame to fasten the new bolts in place. I do not weld well. Is there some type of self-locking bolts that could be safely used to anchor the motor? I am thinking there should be nuts attached as there are now. I sincerely appreciate all your help. Cheers.
92 Sunbird LE
Well-known member
Most of the time is just nuts and washers , there are nylon insert nuts that dont need lockwashers.( its kind to hard to hold a washer up inside the frame to put the nut on)
http://en.wikipedia.org/wiki/Nyloc_nut
Dont know if you can get the combo washer/nut at any hardware store. (Would work good with LocTite)
http://www.fastenal.com/web/product...TLQRJ!-254826502!-1373660631?isPunchout=false
Doug in P.R.
http://en.wikipedia.org/wiki/Nyloc_nut
Dont know if you can get the combo washer/nut at any hardware store. (Would work good with LocTite)
http://www.fastenal.com/web/product...TLQRJ!-254826502!-1373660631?isPunchout=false
Doug in P.R.
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