What is the difference in these heads? Is one better then the other?

 

Assuming you are referring to the small block heads, they both have he same size valves but the D8's have much larger combustion chambers, so CR will be lower. The later E7 heads most likely have better shaped ports with smaller smog bumps on the exhaust side too.

 

Kewl that is basically what I was wondering. So I guess the E's would be better on this 302 then the d's. But I may put the D's on to give me time to try my luck at porting the E's. Being new to ford's I am not sure how much I can get away with but I will soon find out :P

The only setback I am really having is I am setting this in a van and am trying to avoid having to remove and replace the engine too many times. Oh well, actually pulling the engine on the van was easier then most car's I have done since the whole front end comes off!

I have a 2 600cfm carbs and holley intake for a 302, so I figure rather then spend the money on new intake and carb to go down to 500cfm, I can better spend the money making the engine breathe better and get closer to the 600 being ideal for this engine. Agree?

 

So, after talking with my mechanic friend we decided to put the d's on to get the engine running and then we can take our time and work the E's to give them much better flow. I found a book that said this 72 302 was a zero tolerance engine? so I would not be able to mill the deck and heads without some piston changes? (thinkin I shoulda stuck with chevy since I know those engines inside out)

 

No need to mill the deck since heads with a range of chamber sizes are available, head milling is not an issue though except in how it affects pushrod length. The early 302 heads had tiny chambers so there's no problem getting more compression than pump gas can tolerate, though the valves and ports are no larger... early 351 heads will get larger valves. You can have the best of both worlds with some late model GT40P heads off a '97-2000 Explorer 5.0, these will produce about 9.5:1 CR on a motor with flatto pistons and flow well enough for about 350hp with the right cam and exhaust.

 

Well, everything is now postponed. Started tearing what I thought was going to be the better block. I removed the #5 connecting rod cap cleaned out the oil, Bearings looked pretty good. No signs of bad wear. The dull grey had worn in spots no signs of copper or brass showing. I stuck in a small piece of green plastiguage and tightend the cap to torque. As I was loosening the nuts I noticed what seem to be a hair on a piston. For some reason I grabbed a rag to wipe the spot and touched the skirt of the piston as I did I noticed that a very small amount of oil squeezed to look like a crack. This was pretty disheartening as I thought I was going to get lucky on the bottom half. This engine had cost me $400 and although I got a tranny FMX that I dont care for, I was happy to think I had an engine that had been cared for. There is signs the engine was worked on once before things such as the #6 piston had been changed and was a different model. This one didn't show the wear that normally is on a piston and as such looked new. There was not even the signs of oil staining on the bottom or side. I also noticed several bolt holes where bolts of incorrect size were stuffed in the holes covered in silicone to keep them from falling out. Some of the water jackets are pretty corroded, a sign that the system was never flushed.

So now the block goes off to the machine shop. The #1 piston bore shows a large gouge in it. and I hope the machine shop can bore it .040in and it be usable. They talked about sleeving but I am not really a fan of that. So it will take them a month to get to it, and in the mean time I am sitting here stressing over the money I had planned to spend elsewhere. Well I guess this gives me time to see what I can do wtih this engine. I will have to call the local salvage yards about the price of gt40p heads if there are even any around. I looked at the cam and it has some pitting look but seems more like the cast it was made from was poor. I will mic the cam tomorrow to see where we stand with that, but the clearances on the connecting rods looked great. At the price of pistons I suppose 8 new is in order. Numerous ones show very very faint hairline cracks that normal eyes can hardly see. The mains showed some copper, and I will have to mic the crank tomorrow. So much more I could talk about but it is getting late and I have to check the brake lights on the misses Monte Carlo.

 

BTW was wondering what probably caused cracks in the pistons.....

 

There's really no way to know the history of the motor and all it's parts, maybe these pistons were used before they were put in this motor, maybe the piston was dropped and used anyway. It could have been overheating.. and I don't mean overheating the engine.. just the pistons. This is hard to avoid on a carbed motor unless the whole motor is tuned rich, ususally the cylinders on the corners run leaner than those in the center, so these pistons have to endure more stress which can lead to cracking. Lots of possibilities.

The only way you can be confident you have a reliable bottom end is to rebuild it. A partial rebuild is usually money wasted, so if your crank is in good shape have the rods trued, have the block gone over and machined as necessary, and when you know what it needs get new pistons and rings and put it all back together.

 

yeah looks like I will have to have the rods done... they measure 2.232 across and 2.242lengthwise. I don't know what specs are so I guess that is off to the machine shop as well. Wonder if it would just be better to have new ones? I really need to get a chiltons for this engine so I am not trying to do guess work on this. of course chiltons want a year online when I really prefer to have a hard copy.

 

How do you match rods to their caps? I have another 302 that a guy was supposedly rebuilding, but I think he screwed the caps up. He said go by the marker and not the stampings on the rods but that don't seem right to me. anyways the engine is very hard to turn unless you loosen the rods and mains,