Will these heads work?

[MerganserMaster]

I have recently picked up a set of cylinder heads for my 1975 302 V8 Bronco, as with the current ones it appears that a rocker stud was pulled loose. The replacement set I bought (for $50) appears to be from an 80s era 302 (mustang according to the seller) and it appears that it would fit on the block fine but there is a "difference" in hole alignment between the heads if you look towards the bottom (technically top when its mounted on the block) between the original and replacement heads. Can I make this work somehow? If not I plan on either reselling the blocks (as I cleaned them up quite a bit from their original condition) or parting them out or something (as they came complete with valves and rockers). Thanks.

Original Cylinder Head :

https://flic.kr/p/2pnrgo6
Replacement Cylinder Head:

https://flic.kr/p/2pnqCiJ

 

[Wild horse 75]

Are you talking about the holes right at the bench? Those are for the pushrods and that’s dictated by the rocker position. So it doesn’t matter basically cause the rockers must be in a slightly different position And the pushrods shouldn’t rub on anything. Real easy to check, drop the heads on without a gasket throw a couple bolts in so it doesn’t move and install a couple pushrods and rockers and see if they touch anywhere.

 

[MerganserMaster]

No, its the ones that are at the bottom of the "piston circles". Its more towards the center in the original one than the replacements

 

[Broncobowsher]

I think he is referring to the coolant passage holes.

What are the casting numbers on the heads? I suspect the original head starts with a Dxxx and the new head might start with an Exxx if it is from the 80s. That will tell us a lot more about what heads you picked up.

 

[Wild horse 75]

Ahh yes I see that now. Yes those are coolant passages. You can figure that out from the head gaskets and block. If the gasket has an opening there and the block has somewhere for that coolant to go it’s fine. I can’t remember off the top of my head what the block looks like since it’s been a minute since I’ve had one apart.

 

[m_m70]

i remember from way back where I had to drill holes in the block to match the coolant passage in the head using a head gasket as a template..........been a long time though.

Found some pics I used for reference. Not sure if this is the best route but it worked for me. Others will chime in for sure...

 

[MerganserMaster]

i remember from way back where I had to drill holes in the block to match the coolant passage in the head using a head gasket as a template..........been a long time though.

Found some pics I used for reference. Not sure if this is the best route but it worked for me. Others will chime in for sure...

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I might do this, as the same issue exists where the coolant holes that are in the block don't seem to line up with that of the replacement heads. Any more details on this project would be greatly appreciated.

 

[MerganserMaster]

I think he is referring to the coolant passage holes.

What are the casting numbers on the heads? I suspect the original head starts with a Dxxx and the new head might start with an Exxx if it is from the 80s. That will tell us a lot more about what heads you picked up.

There's a "E8S1" on one of the replacement heads, and on the original one I have not looked for a number yet but I'm guessing you are right.

 

[Oldtimer]

When I put 289 smog heads on my 351W, the water jacket holes did not match.
I used the head gaskets to figure out where the holes did not match.
I used a coat hanger to to probe the water jackets, and figure out where added holes would hit coolant.
It was 35 or 40 years ago, but as I recall, I drilled heads, since they would be easier to replace then the block, if I screwed up.


Looks like D6OE and E8SE

 

[Broncobowsher]

I would punt this to a small block speciality forum.
With that I will add I have seen small holes (3/16"?) in one part but largish holes in gaskets and on the other part.

The majority of the water flows into the block at the waterpump. Flows to the back of the block. Up into the head. Then through the head to the front. Exits the front of the head into the intake manifold. The holes between the block and the head, not at the back of the block, are there for cooling a specific spot. The heads are universal (fit either side). Depending on which bank they are installed on the flow left to right or right to left. So there will be extra holes in the head that must remain blocked at the front of the block. This is where some people have made mistakes with head gaskets, typically the right bank. Put it on upside down and the block off for the front of the block is now at the back and there is almost no flow through that head.

 

[Quick & Dirty]

I think those are E6SE. They are a high swirl head, note how the chamber wall wraps tightly around the intake valve. They don't flow as well as the earlier head. Only used for one year on the HO engines before they went to the E7TE head which has a similar chamber to the old head. They were used for several years on the non-HO engines. They will work fine on a stockish engine with mild cam, but if you are looking for performance, or using a roller cam, there are better heads. You'll need different pushrods to work with the pedestal rockers.

 

[MerganserMaster]

I think those are E6SE. They are a high swirl head, note how the chamber wall wraps tightly around the intake valve. They don't flow as well as the earlier head. Only used for one year on the HO engines before they went to the E7TE head which has a similar chamber to the old head. They were used for several years on the non-HO engines. They will work fine on a stockish engine with mild cam, but if you are looking for performance, or using a roller cam, there are better heads. You'll need different pushrods to work with the pedestal rockers.

To get these heads to work would it require changing the camshaft? I understand that it may result in better performance to do so but right now I just want the engine to run. I'm currently having issues with it backfiring when turning it over (which I believe is due to the valves not opening/closing right), could longer push rods alleviate this? Thanks

 

[Wild horse 75]

Camshaft doesn’t matter to heads except for flow rate when looking for performance. Camshaft matters to crankshaft and firing order. I have a feeling you’re out on your timing.

 

[MerganserMaster]

Camshaft doesn’t matter to heads except for flow rate when looking for performance. Camshaft matters to crankshaft and firing order. I have a feeling you’re out on your timing.

I think so as well, I have the timing set to 0 degrees right now (TDC according to the shop manual I have) and it was originally at/around 30 (but this had the same backfiring result as well and may of not been right). I noticed a small dab of faded paint at 10 degrees, so I may set it to this and see what happens. I remember from when the heads were off the pistons hit the carbon ring left from combustion at approximately 30 degrees so I know that it is close to that number. I have a timing light, but it is not as effective when the engine isn't running.

 

[m_m70]

I have the timing set to 0 degrees right now

are you sure it's on the compression stroke??

I noticed a small dab of faded paint at 10 degrees, so I may set it to this and see what happens

That's a lot closer to where it will need to be in the end

the pistons hit the carbon ring left from combustion at approximately 30 degrees

So are you saying when the #1 piston was at the very top of the stroke the balancer showed 30*??

 

[MerganserMaster]

are you sure it's on the compression stroke??

That's a lot closer to where it will need to be in the end

So are you saying when the #1 piston was at the very top of the stroke the balancer showed 30*??

Problem solved, it now runs

You were right, didn't have it on the compression stroke. I had to flip the plugs on the distributor (after confirming it was on the compression stroke through a variety of methods), I had to switch 1 with 6 and etc. so I was back to being on time. A little bit of gas and starting fluid and it fired right up (for the first time in 20+ years!). Now I have to check for coolant/overheating issues as well as tune/time it so it idles better. Big thanks!

 

[MerganserMaster]

Update: (for anyone who has to deal with drilling holes in the future) I have put a couple hundred miles on my Bronco so far in weather ranging from 40 F to 90 F and have not experienced any overheating issues. All I did was put the new headgaskets on and used a punch to mark where to drill and was able to put all 8 holes in with just a cordless drill and milwaukee drill bit.