I just bought a 78 bronco with a 400 and c6. The engine has been rebuilt but don't know to what specs. I do know it has a edelbrock performer 400 intake. It has a 1406 edelbrock carb. Long tube headers, a msd distributor and a 6al box. I'm guessing it has a mild cam because how it idles. I am curious if the 600 cfm edelbrock is enough carb? I checked the timing and it was at 12 degree btdc which I think I read is about right? Anything else to check?

 

Cato? Don't you mean East Oklahoma? I thought the town sounded familiar, so I looked it up on Google maps and it stuck the pin in Attwoods. Anyway, might you be interested in our Okie get-together next year? We have it in Skiatook.

Anyway, welcome to the club of 400 owners. The 1406 is adequate if you don't wind that thing up too much. And the key there will be two things - compression ratio and cam, as even stock heads flow fairly well. You've already said you think it has a mild cam, which probably means it has a straight-up timing set, so let's talk about pistons. And, that's a short conversation because there's only one place to get a piston that will decent CR - Tim Meyers. But, if Tim's pistons weren't used then you are looking at about 8:1, and it isn't likely you'll be winding the engine enough to cause the 1406 to be a problem as low compression engines just don't like to wind.

 

I like in central Arkansas. I don't guess there is anyway to tell compression without tearing it apart?

 

Not really.

 

Well 8:1 kinda sucks

 

If you have a bore scope, or access to one, you might be able to determine what pistons you have by looking at the top. But, almost all will be the dished ones that limit the CR to 8:1ish.

 

I might can find one. What's about the most hp I can get with 8:1? Is 300 even doable?

 

Dunno. No one puts one with that CR on the dyno. But, I do know that even a stock 400 with a straight-up timing set, and an Eddy intake and 1405 carb runs very well. So, with your headers and cam it might be very strong.

 

What about timing does 12 degree sound right?

 

Yes, 12 is pretty good. But, if it'll run w/o pinging, detonation, or run-on at a bit more I'd try it. Low compression takes more timing.

 

I'll pump it up 2 degree and see. The guy I got from was wanting to put some Holley double pumper ultra carb on it. It seems to run pretty good with edelbrock so hard to mess with it

 

Don't get me started on the Holley/Edelbrock debate. But, for daily driving I'll take an Eddy 8 days a week. Second would be a Street Demon or a Q-Jet. Racing? I could be coerced to go with a Holley, but the others will work if properly set up. (Oh, wait! You got me started! )

On the timing, are you running vacuum advance? If so, where is it connected?

 

The msd distubator doesn't have a vacuum advance it has a msd red box mounted on the fender

 

What a waste - of gas and money. Gas because w/o vacuum advance you cannot get max MPG. And money because the stock DS-II ignition is more than you need.

So, w/o vacuum advance you will want all the initial advance you can get. However, the MSD doesn't have the ignition retard feature that the DS-II box does, so you can't go too far w/o it kicking back when starting. But, you want to be up close to that limit.

 

I bumped it up to 16 and no pings