low power 69 427/390

[Clem Z.]

Re: low power 69 427/390

Clem...received rods today and installed. No real improvement. Feels like it's just not getting all the gas it needs. Going to pull carb and check float level.

get a inline fuel pressure checker and see what the fuel pressure is under a load. also check and see if the carb has a windowed needle seat. checked the diameter of the inlet of the needle seat. make sure the fuel filter is not installed backwards or is not plugged.

[Jack H.]

Re: low power 69 427/390

Will it climb to red line?

If the secondaries aren't opening, you can forget about reving much beyond 4K RPM...

[Clem Z.]

Re: low power 69 427/390

have you checked the timing with a light to make sure it is advancing with RPMs and is set correct ?

[Bill C.]

Re: low power 69 427/390

Thanks Bill...at this point I'm going to pull the carb, tear it down and rebuild. I bought it as a 'rebuilt' carb from a builder that may be questionable.

[Bill C.]

Re: low power 69 427/390

• Disassembled carb, adjusted float, found and ground down a small casting bump in secondaries that might have impacted opening, sealed up some leaks...everything else looks ok. Test drive...some small improvement but not where it needs to be. RPM's will climb but soften up above 4K. Haven't got to redline. I'll take another look at the secondaries. Next on my list is the distributor. I'll recheck timing and advance.
• Bill

[Gene M.]

Re: low power 69 427/390

Bill,
Check out the rocker arms for excess lifter clearance that could be a sign of wear on cam lobes or lifter faces.

I have found issues here due to either poor oil lubrication on flat tappet cams or bad parts...........

Engine ran ok, not great, till I tried to wind her up then it acted like your's.

[Bill C.]

Re: low power 69 427/390

Turns out it's the simple stuff that gets you. Took another look at the secondaries. Marked the accel cable (it was new) for travel when I floored it...with a flashlight in hand I manually moved the linkage to that spot and ...bingo...secondaries were barely opening. What I thought was full throttle wasn't. Turns out I had about 5/8" of travel still to go before they fully open. Took out some carpet insulation behind the gas pedal and took all the play out of the accel lever...bingo...finally found a bunch of those 390 horses. Still plan on checking the ignition side to be sure all is as it should be... Thanks to all you guys for the advice

[Dennis S.]

Re: low power 69 427/390

Turns out it's the simple stuff that gets you. Took another look at the secondaries. Marked the accel cable (it was new) for travel when I floored it...with a flashlight in hand I manually moved the linkage to that spot and ...bingo...secondaries were barely opening. What I thought was full throttle wasn't. Turns out I had about 5/8" of travel still to go before they fully open. Took out some carpet insulation behind the gas pedal and took all the play out of the accel lever...bingo...finally found a bunch of those 390 horses. Still plan on checking the ignition side to be sure all is as it should be... Thanks to all you guys for the advice

I hate to say it, but I told you to check it first.............

[Clem Z.]

Re: low power 69 427/390

i used split shot fishing sinkers on the one side of the throttle cable under the dash to shorten the cable or you can take out the foot feed,how do you like that old term, and put it in a vise to bend it. you still needed the secondary rods so all was not lost.

[Tom L.]

Re: low power 69 427/390

I had this exact problem when I bought my car. To compensate for the insulation is simply shimmed out the plastic piece that holds the "foot feed" to get the appropriate throw of the pedal.

[Bill C.]

Re: low power 69 427/390

Dennis...no doubt, you called it. Cable was new and traveled smooth. 'Assumed' all was well. Not the 1st time I didn't pay attention to good advice. Thanks again...
Clem, Lynn...Good suggestions on getting more cable travel. I do need it in order to put the floormat back in. I was thinking of shimming the pedal mount. The shot is interesting as I'm looking to get another 1/4-3/8" of travel...

[Tom L.]

Re: low power 69 427/390

I took my time and made a billet aluminum shim that fit the bottom of the pedal mount exactly. It was a bout a 1/2" thick. In hind sight I think it may be an 1/8th of an inch thick. The pedal is a bit high. Good luck with the release of your horses!