My son just installed a set pair of Flowtech Red Hots Glasspacks on a 76 F150 with a 302.
Not long after (the same day) he started having carb problems (MC 2100). These were addressed and fixed (accellerator pump leaking). I'm just putting this down as coincidental.
Hard starting continued but we got it worked out so the truck starts and runs.
I am questioning the glasspacks he just installed. Is it possible that these are on backwards and causing too much backpressure? The motor runs - it just seems to be under a strain. He's 14 and proud to working on this truck and I don't want to suggest to him that his swap could be causing any of this if it isn't.

 

Putting glasspacks on backwards is about the same as running straight pipes. The exhaust just doesn't flow through the little fins in there. If it did somehow cause your problem then I learn something new. A few years back we installed a lot of glasspacks backwards because they wanted their cars real loud so it sounded just like straight pipes but had "mufflers" to pass inspection. These were not Flowtechs so I don't know if they are designed different, but I'm thinking its all just a coincidence. I even did this on my old Dodge and put a ton of miles on it with no trouble.

 

Thanks. I've had the same thoughts but I'm reaching for straws. Something did occur to me though, I never had him check the pcv. Could be clogged or stuck causing the problem. It's my first thing on the check list when I get home.

 

When you say under a strain when it runs do you mean under a load or at idle? Maybe you don't have enough fuel going to carb. like a clogged fuel filter or something. What exactly are your symptoms currently? I see you fixed the carb. and hard starting if I'm reading correctly .

 

Good point. Let me explain strain. It's almost like a vacuum leak or timing that is retarded.
The carb was dumping too much fuel. We fixed that, pulled and cleaned the fuel soaked plugs. Got it back to running. Sprayed carb cleaner at all suspect points looking for vacuum leaks and found none. It responds well to the throttle - no lag, sputters or backfires. The idle speed in park is higher than I would like. If I lower it any it dies when you put it in gear.
When I get home I'm going to check the pcv and check the timing to find out where I really am - till then we're all guessing.

 

Please read through this.

https://www.ford-trucks.com/forums/8...the-pedal.html

FMC400 gives a link to a great response on how to properly deal with getting your idle right. It might help you with that aspect. You also should check the timing first then set your idle.

 

Thanks. great info.

 

Readjusted the carb and got the fast idle cam much closer to where it should be - things ran much better. Shut it down to set the timing and couldn't get it to run until it cooled off (what now?).
Got it running and found the timing to be WAY off. Believe it or not it was purring at 35 BTC! Anyway, upped the idle speed and set the timing at 6-8 BTC @1200 rpm. It's much better but I want to know it's right. I've posted in the 302 forum for a factory spec on the rpm since the under the hood sticker is long gone. I seem to remember using high manifold vacuum to find this unknown setting once upon a time but I'll need a box of memory pills to help me there!

 

My 302 is set at 6 BTDC and it works well. My high idle is around 1,000rpms or so.

 

What is the recommended RPM to dial in the 6btc?

 

I always set the timing first then adjust the idle. 1000-1200rpms should be fine. My curb idle is around 600rpms when choke is open