So I have a pair of C8AE-H heads with CJ size valves, 71cc chamber, hardened seats, hi perf springs (up to .600 of lift), etc. the works. I was wondering what the compression will be... they are going on stock 390 bottom end, edel perf. intake (yes i know i need the rpm but it's what came with it lol), edel 650cfm carb.

Also this being the first time i have installed heads myself is there any tips/tricks or things to watch out for to avoid problems? And can i use my rocker assembly from my d2te-aa heads on these? and what about lifters?

any help would be greatly appreciated!

 

Compression depends on year of the 390, most were in the 9.5:1 to 10 range.

I prefer the use of studs vs bolts, they torque more even. Your rocker should transfer across but I haven't a clue on pushrod length and lifers.

Some one with more knowledge than me should have the answer.

My Edlebrock Al heads are suppose to be similar to your heads. I use the Holand Sharp roller rocker on top of mine. They are adjustable but required a different length pushrods.

 

I'm basically trying to take on a task I have never tried (just how i roll ha) and am trying to learn everything I can before starting. Truck is daily driver and can't be down long so getting it right the first time and having all the parts I need would be nice.

So any info on swapping heads would be awesome. Been lookin over lots of old threads to see if there was an answer but most are too smart for me at the moment.. some very in depth and learned folks on here haha. Way over my head, so I had to just come out and ask the dumb ? myself.

Thanks in advance
Jeremy

 

Are you just changing the heads or other improvements?

If you doing this in the truck. Do your self a favor and remove the hood, it will give you more light and easier access. If you have the original cast iron intake that weight 90Lbs, use a crane if you have one or get some one to help you. You don't need to break your back on it. Make sure you disconnect the battery, drain all of the fluids, antifreeze & oil. The new heads may require a different pushrod length, someone else should answer this question that is familiar with these heads. I have adj rockers on mine. The push rods can and may be different length, so keep up with which hole they came out of. I use a 4x4 block of wood, drilled to hold the rods. Soon as you remove the intake, cover the top of the engine with a towel to keep debree out. Cleaning the block around the pistons can be a chore depending on how bad it stuck. Take your time these surfaces must be clean inorder to get a good seal. Use a shop vac to help with the cleaning. I like rags in the cylinder to keep the finer stuff away from the walls and rings. While you have the intake off you may want to replace it with an Al one, that will save 80 lbs and your back. The area that like to leak oil is the strip that runs between the heads front & back.

You should finish in 1 day. Other may have more to say.

Good luck

 

Thanks, there is an edel. performer intake already on it so the heads are the only thing I'm changing right now. The old ones were annoying with valve problems and it cost less to buy these with the CJ valves than to have someone do a valve job on my D2TE-AA heads so it was the natural choice.

It sounds like I just need to know the pushrod lengths.

Anyone want some D2TE-AA heads?

 

I have heard the perf. intake is a good intake. those D2 heads should be real simular in chamber size, but someone back me up here!

 

I would measure the thickness of the two heads, but you want the parts in hand before you tear down so that doesnt help. one thing that will hepl is to measure the valve installed height to make sure they didnt do a terrible job with the valve grind. if you have hieghts all over the place you might end up with length problems on your pushrods, plus its a bad sign on the machine work.
btw, did they intall hardened seats in the exhaust side?

 

yep hardened seats, new guides, springs, everything. From what I know the D2 heads are basically the revised C8AE-H heads so they should be very similar.

 

what is wrong with the D2 heads? looks like your in waco. I am just south of you outside of Austin. I might take them off your hands.

 

That is correct. If the head has been milled there may or may not be a problem with pushrod length. Maybe Brian (polcat) can get you help with measuring them.

As far as how much can come off before it matters? I can't help you with that, one of those other ya-hoos will have to chime in.

 

Am I incorrect in recalling the CJ sized valves (may)require notching the cylinder walls ? Probably am been a year since I looked at the book on the stuff. If your just changing heads over and using the stuck cam and old lifters. Lifters must go back where they came from or get new. Do you know the open spring pressure at the lift of the cam in it? (do they match the cam?) If these things are in order and the valve tips are straight (use a straight edge across the tops) Then if using the non adjustable valve train be sure to see the tech article "Nasty little secret, bent push rods"

https://www.ford-trucks.com/article/...le_Secret.html

 

I'm not completely sure what all is wrong with them, the passenger side has had this "tick" that sounds like an exhaust leak but isnt, though many people have "named that sound" since i've had it... annoying yes i hear it and no it's not new lol. The driver side was fine until recently. It started blowin smoke out of that side exhaust and I came to find out that one of the rocker bolts had been torqued too tight and striped the head. So I had it heli coiled but it still burns oil from that side.

I plan on using the rocker assembly from those, at least for the time being (poor man = one improvement at a time)

Thanks for the link Redmanbob!! I dont know if they match the cam.. how do i find this out? I'm 21 and experience is not on my side yet. so sorry for some of the basic questions.

 

The engine supposedly only has about 13,000 miles on it, well the guy had this dinky reciept anyway. but paint was still good on it so it might be, but as for the heads i dunno if they've been rebuilt or anything, havent taken them off...yet.

 

well, save up some money and get a good cam to match those good heads. that way you can take full advantage of the heads and you will know your spring rate as it is specified with the cam. you will need new lifters, springs and pushrods, and you may want a new timing gear set. but this will really wake it up the most. the cam install can be tricky not to scuff the soft bearings going in and taking the old one out. most poeple use a piece of all-thread 7/16 coarse thread about 18 inches or so for leverage taking the old one out and installing the new one. this may be more than you want to do, but just a thought.

btw, new heaads on old bottom end? I heard an old wives tale that this causes your rings to start leaking more. or at least you start noticing them more with the better seal of the valves. you may be ok with only 13k on the engine.

 

Cause the rings to blow? More like make the next problem apparent. I think you'll be ok with a low mile engine. It's not like you had low compression readings and decided on head work.

Good catch on the cylinder clearance Redmanbob, I still have not searched that one. I remember a thread on the other forum, but don't remember the specifics.