390ci 2bbl to 4bbl Conversion

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Jun 5, 2005 | 10:06 PM

#16

"Beemer Nut"

Post Fiend

Joined: Dec 2003

Posts: 6,658

Likes: 4

From: "Islander"

Chris, on your headers I have Thorley's on my 68 CS but I have no front anti-roll bar. Far as carbs I installed a basic stock 410 with headers on a friends 69 4 x 4 with 4 speed. With my new Holley 670 SA it was more responsive lowend
to 1,800 rpm's than his new Holley 770 SA. This is under normal conditions, not a street 4,000 rpm launches street race vehicle. My 410 which is geared taller, more cam and head flow, 3.54 with 32" tires and off idle pulling tight convertor responded about the same on 670 SA. Unless you need to impress the school kids, don't over carburate. The discussion was on 600 to 770, split the difference and go 670 SA, plenty oversize for your motor. Island neighbor.
.....=o&o>.....

Jun 7, 2005 | 01:08 AM

#17

samckernan

Senior User

Joined: Nov 2003

Posts: 215

Likes: 0

From: Planet Earth

Quote:

Originally Posted by Chris 73

I appreciate the help. I will use a 600 cfm carb with the intake. I have no intentions of building a high performance engine. The only upgrades I have done so far have been rebuilding the engine from a 360 to a 390 and a dual 2.5" exhaust system. I may go with headers in the future, but all of the headers I have seen say they will not work with the Camper Special trucks.
Its a '73 F250 by the way.

Chris

Like Beemer Nut said, see if there is a sway bar that would interfer. Some of the trucks have them crossing in the rear of then engine, some have them crossing in the front of the engine, and some don't have the sway bar at all. Mine crosses forward. I have headers by headman on my 72 F250 Camper Special.

Also running a Holley SA670. It seems to work fine.

Just my $0.02.

Good luck.