So i have a 351M in a 78 bronco, ( sig says 400 but it isn't confirmed yet.) and i read on a different thread that the standard OEM timing is retarded for emissions standards. this thread also said that advancing the timing would give it more kick. I was thinking about this and wouldn't that raise the RPMs causing more fuel consumption? Then wouldn't you tune the idle speed screw to throttle it back down a bit? I am going to get a new 4bbl Edlebrock intake and Carter carb soon and if i can squeeze more performance out of it then i would be pretty happy.
Thanks.

EDIT: this is the link
https://www.ford-trucks.com/forums/1090143-351m-hp.html
Post #6

 

It might help a little. I can't say for sure if you would notice any change in MPG, but a little SOTP might be noticed. (Seat Of The Pants). As you may have already been told or may have read, installing a new timing chain will eliminate the 4deg retardation and will def give you more oompf, and so will the Eddy intake and Carter carb. Just don't expect your mileage to stay the same. When my truck was bone stock with the 31in tires I was getting 13mpg on the freeway. As it sits now....10

 

Ya my mileage isn't good as it is so it can't get much worse. That isn't so much my concern though, So without replacing the chain i just advance 4 degrees from where i am and shoot for what RPM? Then i will see some change?

 

yes a upgraded timing chain will help on torque/hrspwr. the effect your really feelin is making your torque converter work properly. i think for our old iron their are some options at a cost for some fuel mileage. Your C-6 has several upgrade options to pull a little mileage our of your truck. modern torque converter! i have had good luck with hughes performance converters. torque converters takes the hrspwr/torque from engine and gets it to the tires. bronco's are kinda heavy and if you can trim some skin off your big girl good things happen. www.autofab.com sells some cool parts for dezert racing which helps skin some weight off bronc. C-6 has low gear kits and kits to help free up some hrspwr being soaked up in tranny. you have a bronc with some potential and now you have some reading to consider. On carbs i'm a fan of quick fuel carbs and their are some other more high end stuff. I checked out you tube and seen your heads are painted or aluminum? whats up! if you get a chance weigh your truck and see how much your big girl weighs? catch you later.

 

Hey thanks for the info. I got my C-6 rebuilt with heavy duty internals, and a modern torque converter. As for my heads, they are the normal Cleavland heads but i think the PO painted them. He said he had a really bad valve tap and had a new used motor he was planning to swap in but the bottom end was shot. He put the other heads on that were good and rebuilt.

 

what is your stall on torque converter? My c-6 has all torrington rollers. no more shims/bushings. frees up friction and helps take heat out of tranny. hughes builds their torque converter with these upgrades to help on these issues also.

 

purchased fenders and hood fiberglass. will be purchasing a aluminum bed. trying to get my weight below 5000lbs. its a 1970 ford crewcab 4wd. autofab hood fenders and many other upgrades and keep capable old iron. catch you later and keepin old iron alive one ford at a time. built 400 ford with some cool parts slightly extreme 4wd 408. many photos in my albums photos.

 

Advance your timing 4 degrees.....then you might have to readjust the idle. Mine idles at 750-ish. Maybe a little more for auto trans.....800 maybe?

 

Remember that advancing the ignition timing affects only that - the ignition.

The retarded cam timing affects the timing of the opening & closing of the valves.

Dylan - read through Bubba's stuff up in the Sticky, it might help you.

 

Oh ok. I'll read the sticky and see what it's all about. I don't know what the stall for a torque converter is, i am still learning what happends inside it. The shop i took it too to have the trans rebuilt already had a full C-6 built up for a work truck (don't know what kind) and the company who was coming to get the trans rebuilt couldn't do it cause i guess they didn't have a c-6. So a tech pulled my internals and put the new ones in, put a new torque converter (I ment new being modern not an old 78 torque converter) and he replaced the front seal on my t-case.

 

some converters have different stalls. some at 1000rpms up to 5000 rpms. Oem is around 1200 to 1500 rpm stall. matching the cam to stall is a big deal. I'm changing the thread but since your not familiar with give some basics. you want your engine to atleast turn twice the rpms at optimum operating rpms. If you max torque/hrspwr is around 3000 need about 1500 or maybe a little less for daily driver. 400 ford stock cam is done on rpms around 4500max. makes good power around 2500 to 3000, divide by 2 and should be close your basic stall converter requirements. their are some other factors to figure in but this is the basic 101 version. find out what your cams prefered rpm range and build off of that. the more you slip/stall the engine the worse the fuel mileage and more heat in tranny. can you read rpms in your truck. rev up engine and see where your engine wants to start moving forward, light foot pressure on brakes and just watch closely on tach.

 

Oh i sort of see now. one problem though... 78 didn't have tachs.. I have one i can install but i have things ahead of it right now (intake/carb)