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Discussion Starter #1
I'm planning a modest upgrade, and have decided to take Gacknar's suggestion on increasing power. 1. Gears, 2. Intake, and 3. Exhaust.

I'm having the tranny rebuilt a little beefier to withstand the strain of the extra torque a little better, and the 4.56 gears go in right after the trans is done. For the intake i'm going with the Edelbrock 3881, a modest upgrade at a modest price. But, it is set up to receive the standard dual throttle body. And, since I picked up a complete stock MAF set up from a 95 BKO, I think I'm set up for parts 1 & 2. As far as exhaust pipes go, the headers will be determined based on the exhaust heads I go with, and the plumbing will be limited by the Carb authorized cat which current look to be a 2.5 in/out.


Being limited by California's emission laws, I'm required to use exhaust heads that have a CARB EO# or are listed by the manufacture as the stock replacement for the OEM part. :banghead The 94-95 Cobra and Lightning heads are the only ones that seem to be taped and drilled for California emissions. All the heads with an E0# seem to run in the $1200-2000 range per set. But, for somewhere around $400-500, I can find a used Lightning block & heads. Or, for around $1600, I can find a rebuilt Lightning.

So, rather than buy the expensive aftermarket heads, I'm thinking of going with the used Lightning. Which brings me back to the original question, are the Cobra and Lightning heads the same? If not I'm limited to only finding the old Lightning heads. And, finally how much better would the Lightning Head be on a 95 roller block versus my 90 flat tappet block. I'd be using something like a Comp Cam 35-255-5 vs the stock cam.:rockon
 

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The difference in the heads will be the mounting bolt holes. The 302 has 3/8" holes and the 351 has 1/2" holes. Other than that, you are good. If you get the cobra stuff, you can also get the crane cams 1.7 rockers that came stock with the cobra's. I do not know if they were factory equipment on the lightnings.

The difference between flat and roller cams will be so small you will not notice the difference. I would have the heads ported a little to open up the pockets. I usually hit the walls and roof of the intake side on a carbed engine leaving the floor fairly rough. This promotes tumbling and mixture which has worked well for me in the past. You should smooth them most of the way down for EFI to have the air flow as smoothly as possible for EFI. May not notice any difference at first with that, but your fuel gauge will notice when you get better mixture at combustion.

SWS
 

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Discussion Starter #4
The difference in the heads will be the mounting bolt holes. The 302 has 3/8" holes and the 351 has 1/2" holes. Other than that, you are good. If you get the cobra stuff, you can also get the crane cams 1.7 rockers that came stock with the cobra's. I do not know if they were factory equipment on the lightnings.

The difference between flat and roller cams will be so small you will not notice the difference. I would have the heads ported a little to open up the pockets. I usually hit the walls and roof of the intake side on a carbed engine leaving the floor fairly rough. This promotes tumbling and mixture which has worked well for me in the past. You should smooth them most of the way down for EFI to have the air flow as smoothly as possible for EFI. May not notice any difference at first with that, but your fuel gauge will notice when you get better mixture at combustion.

SWS
So, I'm guessing that since the holes are different, that the part # are also different. Does anyone know what the actual numbers are and where they are embossed on the heads? I have to go before a Carb ref to determine what criteria the new engine will be tested under. He's also going to ask for Carb EO# for anything not stock.

The rules pertaining to Heads are: "Replacement heads must be identical to the original part. Head swaps from different years, engines or makes are illegal. Aftermarket heads or valve train components that are not made to the same specifications as the original parts require an Executive Order to be legal for street use."

So unless the part numbers are the same or not readily visable, I'm going to have to go with the Lightning heads. The idea is to have the engine tested as an 94-95. What a PITA.
 

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The difference in the heads will be the mounting bolt holes. The 302 has 3/8" holes and the 351 has 1/2" holes. SWS
7/16" vs. 1/2" actually. The "lightning" heads will have a slightly larger cc volume which will equal slightly lower compression.

With all the GT40 iron heads floating around, I don't think you'll have to look too hard for a set, but they may have never been on a lightning or a cobra. Ford probably sold more over the counter than anywhere, but also put them on 96--97.5 explorers and mountaineers. The exp and mount. heads have slightly larger chambers still (I think), poor valve springs, etc. But, a proper clean up and new valve springs are probably in your plans anyway.

hth
tim
 

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He's also going to ask for Carb EO# for anything not stock.

The rules pertaining to Heads are: "Replacement heads must be identical to the original part. Head swaps from different years, engines or makes are illegal. Aftermarket heads or valve train components that are not made to the same specifications as the original parts require an Executive Order to be legal for street use."
Wow...where is the safety concern in this? It should be illeagal to impose that kind of crap on the public. It is supposed to be SAFETY concerned. I would throw a used GT40P engine in it with a set of factory explorer manifolds. Tell them it is factory stuff and see if it passes. Now, you can not pass the P heads off as stock because they have different plug angles that keep you from using your exhaust.

I will never live in Cali. I would love to see someone take office who was actually for the public in stead of his pocket.

SWS
 

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Discussion Starter #7
7/16" vs. 1/2" actually. The "lightning" heads will have a slightly larger cc volume which will equal slightly lower compression.

With all the GT40 iron heads floating around, I don't think you'll have to look too hard for a set, but they may have never been on a lightning or a cobra. Ford probably sold more over the counter than anywhere, but also put them on 96--97.5 explorers and mountaineers. The exp and mount. heads have slightly larger chambers still (I think), poor valve springs, etc. But, a proper clean up and new valve springs are probably in your plans anyway.

hth
tim
As far as I can find out, the explorer/mountianeers aren't drilled in the back of the heads to except the Thermactor crossover pipes. That's why I need the Cobra or Lightning heads.

I have the casting number for both the 93 and 95 Cobra GT40's, but I can't find the number of the heads used in the 95 Lightning. There were some that thought F1ZE, but Ford's code breaks that out to a 91 Mustang engine number. And, I don't believe the Mustang had a 351w in 91.

But, the casting number is only visible by removing the lower intake manifold so they probably don't go to that extent to check. It just would be good to have a sales receipt that says what I have.
 

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Discussion Starter #8
Wow...where is the safety concern in this? It should be illeagal to impose that kind of crap on the public. It is supposed to be SAFETY concerned. I would throw a used GT40P engine in it with a set of factory explorer manifolds. Tell them it is factory stuff and see if it passes. Now, you can not pass the P heads off as stock because they have different plug angles that keep you from using your exhaust.

I will never live in Cali. I would love to see someone take office who was actually for the public in stead of his pocket.

SWS
Actually, if you've ever been to LA you'd know it's a health concern. They can't see the hills around LA on a good day. On the bright side, if you can't pass smog, and can't afford to fix your car, they'll buy it from you or pay to have it fixed for you. Amazing how giving my money away, doesn't seem to bother them.

But, the rules do seem to make it so hard to do anything with old vehicles that you'd think they just want you to take them off the road.

Take the exhaust situation. The smog laws say that you can put any cat in that is listed as a replacement for the oem original in the manufacturers catalog. There are only 3 manufacturers that list oem replacement in their catalog. Two of them have two 2" in and one 2.5" out ports. But the headers for the truck has a 2.5" collector at the flange. So, I guess that they want you to put a 2.5" to 2" reducer somewhere in between the headers and the 1st cat. :barf After that the 2nd cats are all 2.5 in & out, and they don't care what size pipe you run thru the muffler and out the back of the truck.

But, that's all they'll let you put on. :banghead And, the numbers are clearly marked on the cat so it's not hard for them to look it up, if they think your cheating.
 

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Yeah...I would make a false tube to bolt on to the heads to make it look like it was functioning. Pull the cat apart, cut the inlet and outlet pipes off and make them have more. However, 2.5 is plenty for the 302/351.

If it was a safety concern, then there would be no mention of years, only the ability to meet the particulate count. I can make a carbed engine run just as clean as EFI (hold your horses you EFI junkies) for the day that it is tested. Making EFI work that way for the year is easy to do as well. Look at it this way, I can take a 71 block, put 92 heads on it, run a cam from one of the 5.0 mustangs, and there would be less than the factory smog stuff. The YEARS of the parts are only important if you just slap them together. BUT, there is no less problem doing that than picking up your parts from some aftermarket company that does not want a calibration code for EGR, O2s, and MAF sensors. It is all smoke and mirrors. And once again, the reason there are only a few that are accepted are because they are the ones who paid out to have their names in the hat.

SWS
 

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Discussion Starter #10
Yeah...I would make a false tube to bolt on to the heads to make it look like it was functioning. Pull the cat apart, cut the inlet and outlet pipes off and make them have more. However, 2.5 is plenty for the 302/351.

If it was a safety concern, then there would be no mention of years, only the ability to meet the particulate count. I can make a carbed engine run just as clean as EFI (hold your horses you EFI junkies) for the day that it is tested. Making EFI work that way for the year is easy to do as well. Look at it this way, I can take a 71 block, put 92 heads on it, run a cam from one of the 5.0 mustangs, and there would be less than the factory smog stuff. The YEARS of the parts are only important if you just slap them together. BUT, there is no less problem doing that than picking up your parts from some aftermarket company that does not want a calibration code for EGR, O2s, and MAF sensors. It is all smoke and mirrors. And once again, the reason there are only a few that are accepted are because they are the ones who paid out to have their names in the hat.
SWS
Absolutely, as the population of any year or model decreases, there are fewer manufacturers willing to go to the expense of having their products tested to qualify for the Carb numbers. So as technology improves, the chances get greater of someone coming up with a better (thing a ma bob) that will improve on the oem part . But, because of the Carb restriction and cost of testing, it will never come to market. Typical narrow government thinking.:doh0715:
 

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you dont want the gt40p get the gt40 heads they are easy to find and they dont have the small exhaust manifolds.
 

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If you are running them box stock the GT40P's flow better. The added compression of the p's is good for low end as well. GT40's only have the advantage once you start porting them and running more than .500 lift at the valve. Or if you are boosting and trying to keep static compression low.
 

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LOL move to Nevada, bro NO SMOG CHECKS there. you can build it as badd azz u want.
Plus then you wouldnt have to worry about your state sliding into the ocean one day...:goodfinge
 

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We can only hope...
 

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Discussion Starter #18
Nothing wrong with P heads as long as you understand the top guys are about 300 hp NA with them. Im sure they could get 450 with some squeeze, but its what you want. So go that way.

SWS
Number 1 need for me is CARB smog certification, and then torque and finally power. The crossover tube in the back of the heads were eliminated in 95 and were replaced with two banks of air injector for 95-96, I believe.

I'm trying to follow this plan for improving power. 1)gears, 2)exhaust, 3) intake and MAF, 4) heads, 5) cam, and 6) roller block and pistons. Having just paid $2200 to rebuild the e4od, it's forcing me to spread the swap over a longer time than I would have liked.

The catback exhaust ended up jumping the gears, because the oem cats were so clogged that I couldn't make any kind of revs, but now that's out of the way it's on to the gears. I have a quote for $2000 to install 4.10's front and rear with a true-trac LS in the rear. So, unless I can find someone with experience in installing gears to give me a hand, I'm going to be tapped out for a while.

Then I was planning to install a Edelbrock Performer Intake and shorty exhaust headers. I'd switch the intake to a 95 MAF and EEC with one of Fire Guys MAF and injector harnesses and hopefully run it stock with all of my 90 emissions.

Eventually the choice in heads will come down to whether or not I stay with my current crossover tubes for the exhaust diverter or switch to the 95 dual bank setup. I know the GT40P heads aren't tapped for the crossover tubes, but I haven't looked into how the 95 air tubes attach. So, I need to find out how they would work with the JBA headers and Edelbrock Performer Intake. I think the safest way to go is keep the crossover tubes by going with the Cobra heads.

Anyone familiar with the 95, air pump and diverter system?:whiteflag
 

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I know you are on a budget, but if you can scoot a bit more of money you could get a better set of flowing heads in a pair of inexpensive Pro Comp 3035 heads.

They have all the smog provisions just like the oe head, can be painted black so they look like a cast iron head too.

I had no problem passing smog with the setup you want on my heads here in CA.

A caveat though, they do not have a CARB eq number. Paint them black and you can't even tell and retain all of your smog equipment.

 

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Discussion Starter #20
I know you are on a budget, but if you can scoot a bit more of money you could get a better set of flowing heads in a pair of inexpensive Pro Comp 3035 heads.

They have all the smog provisions just like the oe head, can be painted black so they look like a cast iron head too.

I had no problem passing smog with the setup you want on my heads here in CA.

A caveat though, they do not have a CARB eq number. Paint them black and you can't even tell and retain all of your smog equipment.

The lack of a Carb # would be a big thing for me. I've looked into those heads and think I'll pass. Besides the need really isn't one of power, since 95% of my driving is between 1500-3000 rpms. I'm just looking for a little more low end torque and I think the GT40s should work fine with the Proformer Truck intake. And, I think they match up well with the Edelbrook 3782 Flat Tappet cam for making low rev power. And, yes they are cheap even after you send them out to be worked on.
 
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