I currently have a cracked carburetor head on my 1986 bronco and was wondering if a EFI head off a 1992 F-150 will fit onto my rig?

The head looks to be the same thing and looks like it will bolt right up to mine. I was wondering if I did this if there is anything to look out for.

If so, will there be any performance difference? I think the combustion chamber on these two heads are different but anything should be better than a cracked head.

What do you guys think?

 

The EFI head should work on your truck. But be aware you will probably have some pinging issues, and will need your distributor re-curved. The reason why is that the EFI head uses a fast-burn combustion chamber, and the carby head is just a normal combustion chamber.

With the EFI head you'll get a raise in compression, from a half to a full point. With the distributor dialed in..this'll make things work even better.

Good luck!

 

I need head too.

 

No comment

 

Boy are you in the wrong forum!

 

Sorry, I like to joke. This just seemed provacative.

 

Thanks for the reply desperado_18_2000. Let me ask you this now, I have a header, cliffard intake, and a Holley 650 double pumper hooked up to that cracked head currently, so you think the efi head would work well or just as well with this set up?

 

P.S. what do you mean about pinging issue?

 

Pinging, detonation, etc., can be caused by hot spots from carbon build up in the combustion chamber, too much advance on the timing, gas that is too low in octane. Because of the fast burn characteristic of the EFI head, adjustment in the timing may be required.

 

Are you sure that isn't too big of a carb for your 300? Don't you experiance major bogs on excelleration?

I've read that no larger than 500 cfm carb. with these engines works best. Most people choose the Holley 390, or something simliar.

 

Right on! I'm excited to see how it performs. The one I have now has three cracks in it, so who knows how much oil or coolant I've been burning over the years. There's always a nice blue tint to the smoke when shes running.

Do you think the intake and header will fit on the same?

 

Nope. You have to modify the alternator bracket and the heat sheild. Invest in some high quality studs/bolts for the header/intake, coat both side of gasket with the copper antiseize compond/spray, and get crimp nuts, not the nylon insert ones. At a good supply house, grade 8 studs with crimp nuts are only a little over a buck a shot. Torque in sequence, and again after it cools. Check periodically.

Check header mounting surface for straightness before installing. Put header inside compartment before installing head, etc. Make sure starter is installed BEFORE header.

Get a smaller carb or you'll be flooding out your engine.

 

make sure all your linkage etc. will mount to your EFI head.

 

Well F-250 Restorer I was told the same thing when I was going through the process of souping up my 300. I have a .245 lift comp cam, Cliffard intake, a header, and the block is bored .030 over.

I called the guys from Cliffard and they said no bigger than a 500cfm with the setup I had or it would be to big, but recommended the Holy 390cfm. I got the same response from the guys from Jegs as well, so I ended up purchasing the the Holy 390 cfm 4-barrel of them.

Put it on, ran great, but you couldn't ever get the 4-barrel to open up up unless you were in the rpm's. Most of it was because it was a vacuum operated secondary. Had a dusty old Holly 650cfm double pumper, mechanical secondary, 4-barrel.

Man I tell you what, I have this thing in a 86 Ford Bronco with 36.5'' TSL's. That thing screams with that 650, that motor WANTS that extra fuel/air. I have that thing tuned beautifully! I go muddling in some wicked terrains, swamps, and bumpy hills, and never bogs down on me.

And yes it is great off acceleration, It can't quit burn the 36.5'' TSL's but if i put some 31's or stock tires on it, I bet I could get them to burn. At least 2nd gear without brake torquing!!

 

Eeeexcellent that's just what I wanted to know as well. Thanks. That's great to hear.

Also, did your lift your bronco or just trim the heck out of the fenders? If lifted, how did you lift the TTB front? Does it behave well with those big tires? Thanks.