1978 Grand Marquis

[Grand1]

Wondered why my float was never center of sight glass....getting some hesitantion on initial acceleration. Messed with the float levels to no avail. Took out my gauge and my fuel pump is throwing out 3 psi. Carb needs 7psi. Time for an upgrade.

https://www.holley.com/products/fuel...EaAh_KEALw_wcB

[DerekTheGreat]

Straighten that out but if your problems still persist, start looking into changing the accelerator pump cam & accelerator nozzles to a larger diameter. I had hesitation on initial acceleration and playing around with those things cured it. Change the pump cam first and if no improvement, then step up the nozzle to the next largest size, go back to a cam with a less aggressive profile. Holley has a chart you can use to see their "lift".

Once that was sorted out, I still had a hesitation issue when accelerating after coasting. That turned out to be fixed by stepping up my main jets. I felt it get better and better until it eventually went away, from 64 or 66 to 72 I believe.

[Grand1]

All good info and definitely on the checklist. Either way, at least it's not an expensive fix. Gonna check and possibly look at spark plugs gap as well. What's your carb? What's it on? I do like this Slayer carb.

[DerekTheGreat]

My carb was a 600cfm Holley with vacuum secondaries. Was on a mild 318, went pretty good after it was sorted out. Slayer? Never heard of that. In any case, figure out what your carb currently has hardware wise (Jets, power valve, pump cam ect..) and get yourself a jet kit from Holley, accelerator pump cam assortment, some float bowl gaskets, the blue reusable ones.

[Grand1]

Here it is
https://www.holley.com/products/fuel...s/parts/HR-650

[DerekTheGreat]

Similar to my old carb but I didn't have a metering block for the secondaries nor did I have idle adjustment screws back there either.

Did you make any adjustments to it or just slap it on? Yours is indeed a 650? Vacuum or mechanical secondaries? Info says they can be sold either way. I prefer the vacuum type, so do most engines

I wouldn't be surprised if you need to step up the main jets and pump nozzles... Not sure about the power valve. "65" doesn't mean much to me, I selected mine by seeing how much vacuum an engine generates while at idle & medium load. Idle pretty much tells you the maximum your engine will make & medium load will be the number you want your power valve to open at. Least that's how I set mine up. Although on second thought I was probably pretty frugal with the PV, used whatever one was set to open at less than 5 or 2.5 Hg.

[Grand1]

Yup it's a 650. I bought it from Carsbycarl...with all the other stuff I moded my engine with. He's a really cool guy and very knowledgeable about the 460....he says this carb was perfect for my mild buildup....and it is .....just fine tuning it. Gonna finally get a tach to get more accurate. I did find a place that sells 110 octane near me. Those idle screws will definitely need to be moved. Lol

[DerekTheGreat]

Yeah, it gives you the flexibility to adjust that's for sure. I got by with my standard issue Holley but something like that is ideal.

What is your compression ratio? You sure you need 110 octane? You notice any pinging now? I'm not an expert but I haven't heard of anyone adjusting idle mixture screws to compensate for octane...

[Grand1]

No pinging, put standard 93 octane in it now. Screws will need adjustment after new fuel pump, if I was unclear. My engine is about 1O- 1. Seen some of the guys in the Ford 460 forum talk about racing fuel

edit...sure it's vacuum secondary as there is one accelerator pump


http://www.460ford.com/forum/37-engi.../topics/195282

[Grand1]

Well got the fuel pump. The inlet and outlet are 3/8 NPT which is different then the inlet butt flare and the threaded outlet.....which means I gonna have to replace the fuel line. No way am I gonna use funky fuel line adapters (some with a 90 degree bends?)to make this fit with my current line....I put a new fuel tank in her already and just reused the old lines....glad I did or I would be replacing them twice.

Nylon tubing good?

[Grand1]

At a crossroads....starting noticing a tick tick tick on my number 3 and 2 cylinder. Took off head covers, installed a bump switch, and did the Exhaust Open Intake Closed valve train adjustment.

No dice. Same noise after I fired her up. The pushrods were not bent, rocker arms looked great. I think it may be a litter, but that means taking off the intake and head! Anyone have any better ideas????

[DerekTheGreat]

Marvel mystery oil or a little bit of seafoam in the oil.

[Grand1]

Well, my problems are in the Detriot area junking thread. Head is off and at a machine shop. Looks like a bent or bending valve, retainer is toast, and the rocker stud was bent. Man, taking the head off is a bitch! 125ft torque, got it out without having to take the hood off, though. Pistons look fine, cam looks good too. Glad I pulled it.

[DerekTheGreat]

So you're not going to slap some performance heads on it??? Now would be a good time. Sucks about the damage though but I'm glad you got it figured out.

[Grand1]

Wish I could man.
The heads I want are $1625 a pair after exchange.
http://www.reincarnation-automotive....nderheads.html
I have about half of that saved for next year.
Being a responsible adult can suck, as my wife and kids get first dibs off my VA disability. The only way I can look at this experience .......is that I have just that more experience taking off cylinder heads ( and intake, and coolant hoses and etc.)