So this my problem. I have rebuilt an 1989 shelby dakota 318 engine. During the rebuild the machinist found that the heads were cracked between the valve seats. These heads are the kidney bean heads which were sort of the cross over between LA heads and the magnum heads. They were only produced for like 3 or 4 years in production trucks and vans. Anyway my machinist tells me that these heads along with the magnum heads have a high rate of cracking between the seats like that. So i go to the salvage yard and find 1990 d150 pull the heads and take them to get done. Again another phone call with bad news that they are cracked too. Mind you that he shows me the cracking when i go back to pick them up. I go through this another couple times swapping the cracked ones for another set from the same years between 88-91. Same darn cracks. Si i found a set off a 1985 360 that looked to be in excellent shape and pulled those. Now these are not the kidney bean heads but i figured that they didnt seem any different. So i had them re worked and installed them on the engine.
Another point to let you know is that these engines are roller lifters motors. Well i got the motor installed got the truck fired up and it runs good except that the valve train sounds like a broken sewing machine running. Alot of excessive noise. A good mopar buddy and engine builder thouhht maybe it was a pushrod issue, so he had a bunch of different length pushrods from .025 over stock length to .175 over stock length and ive tried them all. The engine wont even fire with anything but the stock length in place.
So obviously its not a pushrod issue. The lifters are brand new, no broken springs (thier new too) or anything else i can readily see.
So i have a 3.9 in another dakota i have and pulled the valve covers off. The 3.9 is a 318 minus 2 cylinders. Uses the same pushrod lengths etc etc. It appears to me that the hole/guide in the head which the push rod passes thru on its way from the rocker arm to the lifter is much larger on my 3.9 vice the 1985 360 heads that i have installed. I chunked the original heads to a scrap bin some months ago so i cant compare the original heads to these earlier LA heads.
So my question is does anyone know if you can use an LA head on these pre magnum dodge roller small blocks?
I think the sound i hear coming from the valve train is that the pushrods are hitting during the travel up and down on those guide holes in the head. Yes both sides are doing it to. Yes i have the rockers in the correct right hand lrft hand locations and yes i have the intake and exhaust rockers in thier correct location too. As you may know the exhaust rocker has amachined out recess for valve spring clearance.
So has anybody had this problem and if so what is the solution? Am i screwed and have to try and find a good set of those pre magnum kidney bean heads?
Thanks everyone for any help you can offer!

any 85-91 318 2bbl motor should have the heads you need. They do have a bigger PR hole and they will hit. You could pull your heads and have a machine shop drill the PR holes bigger but they better check and see if there gonna go into the port first. You could also do it with a grinder and a lot of time. The 360 heads kill compression and TQ on those TBI engines.

You are correct about the push rod holes and the cracks. What you "had" were swirl port 302 heads. These are good heads but hard to find crack free. They were used on roller 318's from about 85 and up, cars, trucks, vans. They do have larger push rod holes for the roller cams.

Not sure what head you found on the 360. But I can tell you that the ports and chamber are bigger than what you had. (think lower compression/performance) on the stock 318. I would guess that the rod holes are too small....

I type slow.... But I agree with Dave on this

I have un-cracked 302 heads on the shelf, I have only seen a few 302 heads cracked, the 714 that replaced it I seen cracked more and the magnums are the worst I have over 20 cracked magnum heads and 4 uncracked ones.

Another option if you just want to get it running are the 308 heads from 89-92 360s, still low compression and all but they have the big holes and bolt directly on.

I wished i would have posted this prior to building the engine. Thanks for stepping up with the much valued info. The 360 heads are or were off an 85 ramcharger and they are not of the closed chamber design, which i did think of the lower compression but didnt think the engine would suffer too much performance loss. But know im going to try and track down a decent set of the right heads. There is a few engine shops both here in san antonio and houston that hopefully they will have a set for sale.
So what is the preferred casting number to look for? The 302 or 714?
Yea the holes in an LA head are roughly 1/2 inch wide and the closed chamber heads are about 3/4 inch wide and that extra width does cover that roller travel. Looking at the l
LA heads i dont think there is enough meat in the casting to either drill or grind it out for clearance. Thanks a million for the help once again.

They're cracked and they were working fine and not leaking. Hmmm. How many thousands of sets of cracked heads are out there working great? We throw away the cracked heads and replace them with another set of heads that are going to crack. Then we will drive around with our newly cracked heads and be perfectly happy.

I would look for either as long as they are not cracked, the cracks in these are not like the magnum, there are consequences.

Another option is the 920 casting heads from 67 273-318s, they have the smallest chambers, best ports of the small port heads, you would need to bore the holes bigger (done exactly that and there was plenty of meat). Old Mopar heads are usually ok running on unleaded fuel but if it is a concern you can add pressed in hard seats and you would have the very best heads for that engine.

The cracking in the 302-714 heads must be from the heat down south or something, I hardly ever see that around here.

Save yourself the worry and hassle, buy a new set of Enginequest heads. They have the Magnum chamber, valves and rocker setup and can be had with the LA intake face. They are much better heads than anything you have tried so far. They are worth another hundred hp over 318 heads with a proper shortblock sitting under them.

Or, go hunting for a 1985-1989 Fifth Avenue. They had the roller cam engine and the 302 heads and were normally very lightly used. My 110K '86 318 heads weren't cracked. But even if they are, what LaRoy Engines said is correct, they come off running engines cracked, with no evidence of water seeping from the cracks. IMHO they can be used as is. The disadvantage is the very small ports, some measured flow as low as 135cfm.

So my answer is cheap, 302s, more expensive, EQs.

R.