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Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
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| | | | Joined: Nov 2002 Posts: 1,002 Shop Shark | | Shop Shark Joined: Nov 2002 Posts: 1,002 | Looking good! That manifold custom?
The blower is centered, the snout is the right length, nice setup. Inliners.org would like to see that.
Larry
I don't own a vehicle that isn't old enough to drink.
| | | | | Joined: Sep 2007 Posts: 12 New Guy | | New Guy Joined: Sep 2007 Posts: 12 | The manifold came from [censored] Larrowe in Oregon. The measurenments are deceptive, the snout actually needs to be lenghtened by about 2 3/4". I'll take care of that once the engine is rebuilt and has the small block damper and pulley mounted. | | | | | Joined: Nov 2002 Posts: 1,002 Shop Shark | | Shop Shark Joined: Nov 2002 Posts: 1,002 | Thanks, I know of Larrowe, they advertise in the 12 port news.
Larry
I don't own a vehicle that isn't old enough to drink.
| | | | | Joined: Aug 2007 Posts: 1,859 Grumpy old guy playing with trucks, cars, and boats | | Grumpy old guy playing with trucks, cars, and boats Joined: Aug 2007 Posts: 1,859 | I hope you are adding a support bracket, or the manifold will crack where its bolted to the head (simple material fatigue issue)
have you considered running an eaton M90 and over-driving it?
The problems we face today can not be addressed at the same level of intelligence we were at when we created them - Albert Einstein Or with the same level of $ - Me
| | | | | Joined: Sep 2007 Posts: 12 New Guy | | New Guy Joined: Sep 2007 Posts: 12 | Thanks for the note Scott. I am going to add double supports from the plenum to the oil pan area. Just my initial mockup at this point. I have an M90 that I rebuilt. The cost of the 471 with everything is about the same as having to construct and fit a manifold and 4 bbl carb for the M90. I also just like the old school look of the 471 with twin 94's.
Jim | | | | | Joined: Dec 2008 Posts: 1,922 'Bolter | | 'Bolter Joined: Dec 2008 Posts: 1,922 | A 94 isn't much carburetor for a 471 at 165 CFM each.
The total CFM you need depends on (of course) engine size, but also how much boost you expect.
The usual CFM calculation gives about 337 CFM at 5,000 RPM.
Math: if you have a 235" at 8 psi (and atmospheric pressure is the usual 14.7 psi), your pressure ratio is 1.544:1.
For draw-through use, the N/A CFM is multiplied by the pressure ratio, in your case the result is 521 CFM, much more than your 94 × 2.
This means you will have quite a bit of vacuum at the carbs at WOT.
Do these have vacuum-operated power valves? | | | | | Joined: Sep 2007 Posts: 12 New Guy | | New Guy Joined: Sep 2007 Posts: 12 | Panic:
The power valves have been manifold referenced to force the power valves open at throttle. The pump was originally used on a 271 Ford flatty with the same carbs running 9:1 compression. My theory is that my little 235 with 8.5:1 will be just fine. My plan is to use it as a driver. So, I am not looking to produce lots of HP but rather to have a unique dependable ride. Thanks for the inputI appreciate it. Every bit helps.
Jim | | | | | Joined: Sep 2009 Posts: 5 New Guy | | New Guy Joined: Sep 2009 Posts: 5 | WOW
Nice job
Congratulations
volker | | | | | Joined: Mar 2005 Posts: 576 Shop Shark | | Shop Shark Joined: Mar 2005 Posts: 576 |
1949 Chevrolet 3100 "When this thing hits 88 miles an hour, you're going to see some serious sh%t." -Doc Brown
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