1967 Corvette 427-435 factory side exhaust had no gain in Performance

[Steve B.]

Re: 1967 Corvette 427-435 factory side exhaust had no gain in Performance

Wow what a different from 2 1/2" like I said before back in 67 you wanted Performance and Horse power your running against the big boys back then on the street, I still think 427-435 is more valuable Corvette with a factory N11 exhaust system

The current market suggests otherwise.

[Steve B.]

Re: 1967 Corvette 427-435 factory side exhaust had no gain in Performance

After hearing about the performance loss with side exhaust but wanting to keep them on my 65 big block, I did some research. I cut my OEM pipes open and it's obvious why they hurt performance so much, especially with a big block. The flow path is 1 1/2". That would be like trying to run a marathon breathing through a plastic straw. The solution, for me and several others, was to build my own using Classic Chambered VettePack mufflers. Not original I know but the performance difference is worth it to me. Joe Ciaravino, RIP, put them on his modified 65 with headers and electric cut-outs. His dyno results were impressive. Back to back runs resulted in 414 RWHP with the headers open, 408 RWHP through the side exhaust. They are a little louder than OEM pipes but sound a lot deeper. Here's a pic. of my OEM pipes cut open.

Jim, that's pretty cool. What was the RWHP with the stock side exhaust?

[Jim D.]

Re: 1967 Corvette 427-435 factory side exhaust had no gain in Performance

Steve, Joe didn't post a dyno run prior to replacing the side pipes but I can guarantee the OEM side pipes would cost way more than 6 RWHP vs. open, long tube headers. My buddy has a Superformance Cobra with a stroked 460 and picked up over 80 RWHP when he changed from the original Superformance side pipes to Classic Chambered.

[Steve B.]

Re: 1967 Corvette 427-435 factory side exhaust had no gain in Performance

Steve, Joe didn't post a dyno run prior to replacing the side pipes but I can guarantee the OEM side pipes would cost way more than 6 RWHP vs. open, long tube headers. My buddy has a Superformance Cobra with a stroked 460 and picked up over 80 RWHP when he changed from the original Superformance side pipes to Classic Chambered.

I agree Jim, that's why I was curious about the difference. Losing only 6 RWHP is very impressive vs. open headers is very impressive.

[Michael J.]

Re: 1967 Corvette 427-435 factory side exhaust had no gain in Performance

The current market suggests otherwise.

+1, absolutely.

[Guest]

Re: 1967 Corvette 427-435 factory side exhaust had no gain in Performance

Wonder if this Collector really care if it had Side Pipe which he paid 3.5 Million for this 67,

[Steve B.]

Re: 1967 Corvette 427-435 factory side exhaust had no gain in Performance

I stand corrected

[Tim G.]

Re: 1967 Corvette 427-435 factory side exhaust had no gain in Performance

Sidepipes will always add value to the vehicle. The rarer the car, the more the added value. When you start looking at the values of a 1967 435 roadster with sidepipes vs without sidepipes in the real world, there's no doubt N14 adds a bundle.

My guess is that the red/red L88 certainly would have sold for more with N14.

[Michael J.]

Re: 1967 Corvette 427-435 factory side exhaust had no gain in Performance

Sidepipes will always add value to the vehicle. The rarer the car, the more the added value. When you start looking at the values of a 1967 435 roadster with sidepipes vs without sidepipes in the real world, there's no doubt N14 adds a bundle.

My guess is that the red/red L88 certainly would have sold for more with N14.

+1, and we all know even a '67 L88 without anything original and built around a trim tag and VIN plate brings 7 figures.........