I found the problem was solved by richening up the Thermoquad mixture screws and advancing the timing. Took it out for a test drive last night and the temps (with a 180 stat) stayed at 190 even after prolonged high speed driving. And no more orange manifolds!Timing had been set at 4 degrees BTDC spec, but it works much better at about 7 or 8 with todays' gas (vs 1978 gas) and the TQ carb will eventually get rebuilt or replaced with an Edelbrock, but for now it seems to be OK. --- Otis Davidson <otisdavidson@xxxxxxxxxxx> wrote: > Remember a while back when the Bus was doing the > same thing? It was a > lean condition caused by the factory Holley that was > on it. I had 30 or so > miles to go,and tried my best to richen it up,to no > avail. > > The fix: Install one of my aftermarket Holleys on > it. A 750 cfm > 4160-3310 with vacuum secondaries. No more > orange-hot manifolds after > that. > > > "otis" <--'79 440 powered 35 ft RV > > ----Original Message Follows---- > From: Mike Pittinaro <mechimike@xxxxxxxxx> > To: mailing-list@xxxxxxxxxxxxxxxx > CC: otisdavidson@xxxxxxxxxxx > Subject: Big Block Red Hot Manifolds > Date: Tue, 28 Jun 2005 20:57:47 -0700 (PDT) > > Anyone care to lend a helping word of advice on what > could cause both manifolds on a 1978 400 cu in big > block to glow red? > > Timing is set to the spec, new t-stat, new fan > clutch, > radiator flows OK, belts/hoses OK and lower rad hose > has the internal spring. New plugs and wires. > Engine > reverse flushed and new coolant installed. New > vacuum > lines and stoppers. Engine has a thermoquad > carburetor. > > My own thoughts are a cracked base of the carb, or > possibly a leaking intake manifold, something that > would cause a lean-running situation. Engine seems > to > idle OK though, and has decent power. __________________________________ Yahoo! Mail Stay connected, organized, and protected. Take the tour: http://tour.mail.yahoo.com/mailtour.html ----------------- http://www.imperialclub.com ----------------- This message was sent to you by the Imperial Mailing List. Please reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm