1969 BB exhaust is 2"?

[Mike R.]

Is the stock exhaust for a 69 BB really 2"? Even for solid lifter cars (including mighty L88 and ZL1 cars!!!). It might be too much for me to put little skinny pipes on my car....I assume that a 68 N11 system would fit a 69?

I know its subjective but anyone willing to weigh in on N11 noise levels compared to standard mufflers or sidepipes?

Thanks

Mike

[Joe L.]

Re: 1969 BB exhaust is 2"?

Is the stock exhaust for a 69 BB really 2"? Even for solid lifter cars (including mighty L88 and ZL1 cars!!!). It might be too much for me to put little skinny pipes on my car....I assume that a 68 N11 system would fit a 69?

I know its subjective but anyone willing to weigh in on N11 noise levels compared to standard mufflers or sidepipes?

Thanks

Mike

Mike-----


All PRODUCTION 1969 Corvettes, from 300 hp base engine to ZL-1, were originally fitted with 2" exhaust pipes.

Any 1968 exhaust system, ALL of which were 2-1/2", can be retrofitted to a 1969. The front and rear pipes (with mufflers) have to be replaced as well as the ox-bow bracket and clamps. This includes 1968 N-11 installed on a 1969. However, finding an NOS 1968 N-11 system would be a real challenge.

[Mike R.]

Re: 1969 BB exhaust is 2"?

Thanks Joe

I would be purchasing a CC N11 system. It obviously wouldn't be origina/correct, in adddition to being the wrong size, it would be aluminiumized.

68 vs 69, I am not sure why the pipes wouldn't be the same. What are the differences between 68 and 69 that would make the exhaust pipes different? AFAIK the engine, trans, crossmember, camber bracket, and rear exit locations are all the same(???)?

When I was young...replacing a 2.5" exhaust with a 3" system really woke up my roller cam, alloy 427. It seems that a 2" system will strangle an L89 a 3.5" has 44% more cross section than 2" and the flow difference is even greater.

Mike

Mike-----


All PRODUCTION 1969 Corvettes, from 300 hp base engine to ZL-1, were originally fitted with 2" exhaust pipes.

Any 1968 exhaust system, ALL of which were 2-1/2", can be retrofitted to a 1969. The front and rear pipes (with mufflers) have to be replaced as well as the ox-bow bracket and clamps. This includes 1968 N-11 installed on a 1969. However, finding an NOS 1968 N-11 system would be a real challenge.

[Joe L.]

Re: 1969 BB exhaust is 2"?

Thanks Joe

I would be purchasing a CC N11 system. It obviously wouldn't be origina/correct, in adddition to being the wrong size, it would be aluminiumized.

68 vs 69, I am not sure why the pipes wouldn't be the same. What are the differences between 68 and 69 that would make the exhaust pipes different? AFAIK the engine, trans, crossmember, camber bracket, and rear exit locations are all the same(???)?

When I was young...replacing a 2.5" exhaust with a 3" system really woke up my roller cam, alloy 427. It seems that a 2" system will strangle an L89 a 3.5" has 44% more cross section than 2" and the flow difference is even greater.

Mike

Mike------


Why it was done we could only speculate on. My guess is that it had something to do with ground clearance. There may have been problems experienced with ground-to-exhaust clearance with the 2-1/2" exhaust on the 68's which were lower-than-previous Corvettes. So, to cure it, they might have figured that they could easily gain a little more clearance by going to 2" exhaust for all 1969's. Whatever the reason, that's what happened----all 1969's were 2" exhaust. It was the ONLY year that 2" exhaust was ever used on a big block.

For 1970, it was back to 2-1/2" exhaust for LT-1 and LS-5 but 300 hp and L-46 remained at 2". For 71-72 only base engine used 2" exhaust; all others used 2-1/2".

[Dan M.]

Re: 1969 BB exhaust is 2"?

Joe

Wasn't it also true that the 68 used a 2" to 2 1/2" transistion exhaust pipe off the exhaust mainfolds on the 327?

Or was it straight 2 1/2 " from the mainfolds back? I thouht the 327 exhaust manifolds actually only had a 2" exit area.

Thanks

[Joe L.]

Re: 1969 BB exhaust is 2"?

Joe

Wasn't it also true that the 68 used a 2" to 2 1/2" transistion exhaust pipe off the exhaust mainfolds on the 327?

Or was it straight 2 1/2 " from the mainfolds back? I thouht the 327 exhaust manifolds actually only had a 2" exit area.

Thanks

Dan------


Yes, 1968 small blocks used 2" outlet exhaust manifolds, so the forward exhaust pipe had a 2"-to-2-1/2" transition section. As a matter of fact, ALL 1966 and later C2 and C3 small blocks used 2" outlet manifolds so any of these cars that used 2-1/2" exhaust had a similar transition section at the forward pipe. The last use of a 2-1/2" outlet small block exhaust manifold was 1965. All big blocks used 2-1/2" outlet manifolds, though.