Harry Mann 68 L78 / L88 Camaro

[Crush]

Originally Posted by dykstra

Great to hear Tim!!

And it will be great to hear, new exhaust?

[napa68]

Originally Posted by Crush

And it will be great to hear, new exhaust?

That's the plan. Considering my options right now. Certainly want something that would be true to the period. The consensus between both Eric and my engine builder the current exhaust could be costing 80-100hp.

The exhaust may also help along the engine vacuum a little bit too (4" at an idle)

[Crush]

“my engine builder the current exhaust could be costing 80-100hp.”

Nice over 500 incoming?!

[napa68]

Originally Posted by Crush

Nice over 500 incoming?!

[TimG]

Merry Christmas, Tim. I can't wait to see the end product.

[napa68]

Eric finished up the carb today. I must say, I was particularly surprised and impressed as he wanted to know some VERY specific things about the build. Including........

-header primary size
-header collector size
-exhaust size
-exhaust configuration
-muffler choice

That in addition to particular engine and vehicle specs. Once again proving there are no "bolt on" parts in a build like this.

I made the choice to make it look like it had been installed early on. My mindset was to give the appearance the carb received nothing more than a carb kit.

Below, is Eric's tutorial as written on Facebook.......

"Holley 4781 850 double pumper for Tim Schuetz of Boulder Motorcar Company.

This one's destined for a "Day 2" style '68 Camaro with a pretty hairy-chested 427 that's running an old school L88 bumpstick. As such, idle vacuum is almost non-existent, so the carb needed a few tweaks to allow it to function on the snotty 427.

Idle air bypass holes were added to the primary blades to allow the curb idle throttle position to jive with the transfer slots. The idle circuit was also recalibrated to provide a suitable range of adjustment.
Boy...all that sure sounds awfully familiar. .🤔...

All that explains why it's idling at 1400+ on my test engine--I wanted to set it up close enough where Tim could install it and get it running without having to futz too much with the adjustments.

This one's set up fairly similar to the 1000HP I built for my chevelle which probably has about the same idle vacuum as Tim's 427.
I've ran the Chevelle's 1000HP on the test engine several times, and obviously when it was adjusted for a nice 900 rpm 12.5-1 idle on the test engine, it wouldn't even THINK about idling on the 496 in the Chevelle--which is precisely why carburetors have adjustment provisions. 😁👍

Oh yeah, before I forget--we sourced this core off of eBay, and it had that big blob of orange silicone sealing off the choke rod hole when we picked it up. I mentioned I planned to remove it and install a brass block-off plate but Tim said he kind'a dug the look of the silicone, so we left it on there. 😉😁"

[Xplantdad]

Eric rocks!!

[napa68]

Originally Posted by Xplantdad

Eric rocks!!

Yes he does

[RPOLS3]

This car was crazy cool before - now it will be over the top.

[napa68]

Progress....... Happy with the preliminary pulls after getting everything broke in. Now run the valves, have a look around, check torque, and switch to Eric's carb.

Tomorrow, some tuning and power pulls