Side Exhaust Pipes

[Paul L.]

Re: Side Exhaust Pipes

I have another question. They offer 2-1/2" and 2" pipes. The 2-1/2" are listed for SB 64 & 65. The 2" are listed for 66 & 67. My engine is a 68 -327 and do not know which size to order. Where is this measurment? Is it OD or ID? I cannot tell if only the block was replaced or anything else. I do know that the Aluminum intake is original (numbers match) What I don't kow is if the exhaust manifolds were retained.
Can you offer any help on this?

[Michael J.]

Re: Side Exhaust Pipes

I'm not sure about that. I don't know what size the '68 exhaust manifolds would be for a small block compared to the C2s. Anyone?

[Joe R.]

Re: Side Exhaust Pipes

Paul,

I believe that's ID. What is the GM number of your exhaust manifolds? What are your plans for the car (flight judging or driver or ???)?

Joe

[William C.]

Re: Side Exhaust Pipes

I assume the car is a midyear with a '68 engine grafted in. If the original exhaust manifolds were used, the ID of the manifold outlet is 2 inches for all smallblock '66 cars, sorry for my previous description as it applied to '65.

[Paul L.]

Re: Side Exhaust Pipes

The car is a 1966 Coupe with the L79 engine. (350 HP) The block is the only thing that was changed but I cannot be sure. I will get the casting numbers from the installed exhaust manifolds and post it later. My intended use for the car is to be a driver. (Keep 'em on the road). Eventually I want to replace these non-factory pipes with original style and I do not want any surprises when I bolt the new ones on.

[Paul L.]

Re: Side Exhaust Pipes

The Left side casting number is 3749965 LH 7 GM
The right side is 3747008 or 3747038 or 3747088 The second to last digit is illegible. then blow it is RH GM. This manifold has a place for the thermal tube to the carb but it is unused.

[Paul L.]

Re: Side Exhaust Pipes

The exhaust numbers are 3747008 or 3747088 or 3747038 Second to last number unreadable (RH)
The LH is 3749965.
What does this tell me?

[Clark K.]

Re: Side Exhaust Pipes

First, your car must be newer than a 1965 #10,000 to have factory-installed side exhaust. If the rocker panel molding hangers/brackets are cut off, rather than bent up under the car, it is still NOT definitive that the car came with factory-installed side exhaust. Many Sting Rays that have been body-off restored have had the original frame welds for those hangers ground away and painted over. It would then take a more thorough examination of the chassis to determine which exhaust the car was "born with".

Since a Sting Ray with side exhaust is worth more, everything else being equal, a LOT of them have had this option added, including mine. It is a big (78 pts.?) originality hit at Flight judging meets but I love the sound and they are stayin on!
-Clark

[Paul L.]

Re: Side Exhaust Pipes

First, your car must be newer than a 1965 #10,000 to have factory-installed side exhaust. If the rocker panel molding hangers/brackets are cut off, rather than bent up under the car, it is still NOT definitive that the car came with factory-installed side exhaust. Many Sting Rays that have been body-off restored have had the original frame welds for those hangers ground away and painted over. It would then take a more thorough examination of the chassis to determine which exhaust the car was "born with".

Since a Sting Ray with side exhaust is worth more, everything else being equal, a LOT of them have had this option added, including mine. It is a big (78 pts.?) originality hit at Flight judging meets but I love the sound and they are stayin on!
-Clark

[Michael J.]

Re: Side Exhaust Pipes

Paul, the VIN number will not tell you where the body was built. Look on your trim tag beside "Body". If it starts with an A it is AO Smith, with an S it is St. Louis.

[Marco H.]

Re: Side Exhaust Pipes

Paul,
As Bill mentioned, all '66 (and '67) small blocks used the same exhaust manifolds with a 2" outlet ID regardless of horsepower rating. However the cars equipped with automatic had exhaust systems with 2" pipes. 4 speed cars had exhaust systems with 2.5" pipes that tapered down to 2" where they meet the manifold / heat riser. I believe the chambers (muffler section) had all the same ID regardless of pipe size.
Hope this helps.
Marco

[Paul L.]

Re: Side Exhaust Pipes

The trim tag does indeed have the "S". That was an error on my part about the VIN No.

[Michael M.]

Re: Side Exhaust Pipes

Hi Paul, The head pipe, the pipe leading from the exhaust manifold, on a correct 66 car with sidepipes is 2 inches and then increases to 2 1/2 inches before it makes those two turns and heads down the rocker area. The earlier (65) pipes were 2 1/2 inches out of the manifold. If your manifolds are 66 or later then they have a two inch outlet. 65 and earlier, high performance 327's had 2 1/2 manifold outlets. They both fit on your block, so you can use whatever you want. If you're not having the car judged, or even if you are, you can use 2 1/2 manifolds and head pipes. The question then becomes, can you get a top flight with a 68 block and incorrect manifolds. I have a 66 L79 with an original engine and sidepipes added later on. When I replaced my rusty pipes and manifolds, I used '65 manifolds and sidepipes. I'm not judging mine, so it doesn't matter. Some cars get a top flight with added sidepipes, but I don't know about an incorrect yr engine (if you even care). Some others will know better. BTW, I bought the sweet thunder "quiet" sidepipes. They are anything but quiet when you jump on it but they are a little tamer when idling and when cruising at under 2500 RPM. They are factory spec except for some packing in the baffle area, as I understand it. The insulation keeps some of the heat from coming under the door as well. I thought they were very well made. I know I'm giving up some performance from the stock sides and even more from stock (for my car) through the rear exhaust. That's one of the reasons I went with the 65 manifolds and straight 2 1/2 inch pipes. I love the look and the sound, but sometimes I like to hear the radio as well. It hasn't lost anything performance wise. Someday, I'll do a body off and restore the original exhaust and then have it judged. Hope this helps you, good luck! Mike

[Paul L.]

Re: Side Exhaust Pipes

Hi Paul, The head pipe, the pipe leading from the exhaust manifold, on a correct 66 car with sidepipes is 2 inches and then increases to 2 1/2 inches before it makes those two turns and heads down the rocker area. The earlier (65) pipes were 2 1/2 inches out of the manifold. If your manifolds are 66 or later then they have a two inch outlet. 65 and earlier, high performance 327's had 2 1/2 manifold outlets. They both fit on your block, so you can use whatever you want. If you're not having the car judged, or even if you are, you can use 2 1/2 manifolds and head pipes. The question then becomes, can you get a top flight with a 68 block and incorrect manifolds. I have a 66 L79 with an original engine and sidepipes added later on. When I replaced my rusty pipes and manifolds, I used '65 manifolds and sidepipes. I'm not judging mine, so it doesn't matter. Some cars get a top flight with added sidepipes, but I don't know about an incorrect yr engine (if you even care). Some others will know better. BTW, I bought the sweet thunder "quiet" sidepipes. They are anything but quiet when you jump on it but they are a little tamer when idling and when cruising at under 2500 RPM. They are factory spec except for some packing in the baffle area, as I understand it. The insulation keeps some of the heat from coming under the door as well. I thought they were very well made. I know I'm giving up some performance from the stock sides and even more from stock (for my car) through the rear exhaust. That's one of the reasons I went with the 65 manifolds and straight 2 1/2 inch pipes. I love the look and the sound, but sometimes I like to hear the radio as well. It hasn't lost anything performance wise. Someday, I'll do a body off and restore the original exhaust and then have it judged. Hope this helps you, good luck! Mike

[Joe R.]

Re: Side Exhaust Pipes

Paul,

One of the best ways to get information on this board is to poke the GM # into the search. I tried searching on 3749965, here's one of the threads that came up:

https://www.forums.ncrs.org/showthre...hlight=3749965

Joe